Fast bass? Slow bass? What's yours then?

I was recently reading the thoughts of someone whose knowledge of AV equipment and acoustics I value greatly. He raised the matter of bass speed being a function of bandwidth. My understanding of his words suggests that fast bass requires higher frequencies. While very low frequencies, left to their own devices, are inherently slow. At its most simplistic, the situation could be likened to having one's ears buffeted by a hot air balloon. Or whacked by a baseball bat. The argument seems logical enough. Pluck a double bass near the bridge and it "quickens up" compared with the soft, plummy depths of open strings plucked near the centre.

Yet the description of likely events in audio reproduction has always troubled me. More so since the arrival of the IB subwoofer. The IB produces prodigious quantities of very low frequencies with low distortion. Perhaps the rumour of slow VLF bass arises from the long history of ported boxes? The artificial augmentation of the lower registers (by port-enclosure resonance) has obvious problems of phase, delay, distortion and inertia. i.e. It only sounds slow because it is. While, repeated almost in the same breath,  a sealed box will avoid all the problems associated with the ported box.

Meanwhile, back at the ranch, the IB suffers no such delay and can bring acres of cone area to the task of bass reproduction. If, as we surmise, the IB produces much less distortion then why should it produce unwanted harmonics? Wouldn't artificial harmonics be vital to providing the upper bass content to "speed up" the bass? The IB, when fed pure VLF signals, should sound slower. As should the rotary fan subwoofer by an order of magnitude again!

Yet the IB sounds remarkably nimble. It can dance with the best of them in the infrasonics. Organ pipes start and stop abruptly. Explosions and doors banging are not only incredibly realistic but move a lot of air. Enough to produce very short and violent movements in doors, walls and ceilings. Completely silent infrasonic (film LFE) pulses can quite literally hurt one's feet by sound conduction through a boarded floor!

Not only did the silent pulse produce a very fast, transient, very low frequency pressure wave-front from the cones. It then had to transfer the power by the medium of the air pulse alone to the surface involved. Doing so quickly enough to produce sympathetic resonance to achieve the violent, physical effect. So even though the floor movement was a very "secondhand" expression of the wave-front "air blast" from the IB.. it was still a very short and sharp movement in the floorboards. How fast is your deep, silent bass?

As a long term amateur audio fan I am not remotely a physicist nor even an acoustician. Yet I hear about bass being inherently slow almost every time I read about the subject online. As if it were a physical law set in stone. It is almost like reading that nothing can exceed the speed of light. But without the massive authority of countless, very clever scientists to back up the assertion. Audio seems not to attract too may headlines from the "heavy hitters" of science. Nobody makes "dumbed down" TV documentaries on exceeding the speed of bass. Well, not yet, they don't.

Does a very low frequency have to reproduce the entire (very long) waveform before it can be perceived as a low frequency? Aren't VLF blasts the accepted way of bombs damaging buildings? Percussive pulses and following rarefactions overcoming the stability of the structure by exceeding its strength. Usually via a perpendicular vector to which it has inherently, very little stiffness. Most buildings are held together by friction and gravity. Provided they don't topple in a gale everybody gets on with their lives.

What would happen if you electronically chopped up a pure, continuous, VLF tone? It could even be done mechanically. Perhaps using a microswitch and variable speed, motor driven cam in one leg of the speaker cable to the IB.  What would one hear? Short blips of the VLF tone? Or something else entirely?  I am assuming that (for the sake of this argument) the IB's power amplifier would not become unstable when so abused.



New cable for Sennheiser HD-380 Pro headphones for home audio.

My 1980s Sennheiser HD-420SL earphones have finally given up the ghost. Pressing the cables upwards towards the headphones sometimes helped but relief was usually intermittent at best. I could have ordered a new cable. They are still available despite the intervening decades. They have little 2-pin plugs where they fit the headphones. Though one has to grasp the strain relief device firmly to get sufficient purchase for removal. Pulling on the cable itself would no doubt shorten the life of the copper conductors dramatically.

However, the '420 SLs would still have the singular disadvantage of being open-backed and therefore largely transparent to ambient noise. I had recently begun enjoying YT music videos but suffered competition from the nearby TV.

I sit at my computer tapping away at the keyboard as I update my blogs or browse as I listen to music. I was never a much of a TV watcher and hate having to listen to the drivel even when I can't see the celebs embarrassing themselves in as many unfortunate ways as possible.

The SQ on YT is not always the best but it does offer a huge selection to help one reacquaint oneself with favourite composer's and artist's repertoire. Fortunately YT continues to make improvements in both sound and picture quality. These improvements further encourage users to upload new material to the benefit of all. (Except perhaps some copyright holders who have never knowingly lifted a creative finger in their entire lives.)

The failure of my headphones coincided with my cheapo computer speaker's own cable failing where it joined the stereo mini-jack. What to do?

Go online and research closed back, circumaural headphones, of course. I had no real clue what my price point would be but it seemed that a small band of manufactures produced so called "monitoring" headphones for studio use within a fairly narrow price band.

I dutifully did my homework amongst the online reviews and forum posts and narrowed it down to my eventual purchase: The Sennheiser HD-380 Pro: Closed back, with decent noise reduction and all in a smart, modern and tidy design.

Being denied open backed headphones and having a dislike for ear buds and on-ear designs helped to avoid the much higher priced models with a clear audio conscience.

The sky really is the limit for those with sufficient ill-gotten gains to spend up to $30k on a pair of headphones and amplifier. Since I have somehow avoided running slaves "for a living" my finances, needs and ultimate choice were far more modest in all senses of the word. For $30k the filthy rich could afford to hire the original artist. Nay even a whole orchestras for a private dose of self gratification. How much is the cost per minute of musical replay over the life of a $30,000 headphone?

I also happen to think that the more you spend on audio components the more you demand of them. That way lies only misery, poverty and the torture of self-inflicted pain. Better, surely, to enjoy what you can comfortably afford and get years of real pleasure out of listening to your personal choice of music? Competition for bragging rights provides no greater pleasure in the medium itself. Only self doubt about your ultimate choice.

And so the rehearsal for its replacement begins. You have already written off your latest purchase as worthless in your own mind. How can it now give pleasure or sway the emotions as you fail to wallow in your favourite artist's renditions? How much extra do you need to pay for a guaranteed shiver down the spine on the fifth playing?

Armed with my list of competitors I compared the popular closed headphones on the dealer's 'tree.' Each has their ardent followers but I found them all too bright on the material being played. Probably an attempt by the manufacturers to grab the potential buyer's attention with exaggerated detail. I asked to listen to the HD-380 Pro which was not on open display but stored in unopened packaging nearby.

The music track changed to something I knew and the Sennheisers immediately presented themselves as worthy contenders without deliberate artifice. The bass was clear and strong with neither overemphasis nor lack of impact. Though still rather brighter than I was used to there was no sibilance at the top end. Nor anything which would set my teeth on edge. I paid and left with my next increment towards inevitable pleasure in the music to come. That the Sennheisers had been favourably discounted would have to do for my own version of bragging rights. Soon forgotten as the years pass and the supposed savings rationed out over the life of the product.

I rapidly adjusted to the brightness as my ears became "burnt in." Though in truth the ear cups do not cause overheating in practice.  (Yes, I know this particular vial of priceless snake oil is not what is meant by the term)  Perhaps 'burning in' is the really just the consequence of enjoying new headphones and its inevitable effect on the wax contents of the ears? Whatever.

What I cannot get used to is the damned cable! Coiled like any serpent of your worst nightmares, it weighs not much short of half a pound! It is ridiculously heavy! Within five minutes I detested it with all the vehemence I could muster. The cable pulled the headband down on my scalp like a lead weight!

The CIA would never get away with this at Guantanamo. There would be an outcry from every hypocritical bleeding heart around the globe if the prisoners were forced to wear HD-380s. "Cruel and unnecessary treatment" doesn't even begin to describe it. Permanently aching neck muscles are the immediate consequence of this particular "rack" of Sennheiser's range of medieval torture devices. In the longer term I could end up looking like a very lop-sided Arnie! And it's all down to the damned, coiled cable!

I am sitting here now with the cable coil trapped between my knees as temporary strain relief. Thankfully, I have a lightweight cable already in the post to replace the good ship Sennheiser's massive hawser.

The new cable will be a dirt cheap 2.5mm micro-jack to 3.5mm mini-jack adapter cable a couple of meters long. If the micro-jack plug fits into the bottomless orifice which Sennheiser have managed to bore with the help of an offshore oil rig I shall be delighted.

I shall report on the new cable's benefits and sound quality when it arrives. I hold no illusions that it will survive being badly snagged but hopefully the plug will simply pop out without damage. Nor do I have illusions that electrons either know or care which medium they travel through provided it conducts adequately and the insulation is not too microphonic.

Despite the heavy cable the new headphones sound fine when plugged into the on-board sound card of my PC to play CDs. Not quite so fine on brief acquaintance when  plugged into the NR818 AVR being fed from the Sony BDP S790. Fortunately the phones sound surprisingly good on many YT videos straight from the PC's internal sound card. Organ videos are interesting for their depth and power though I miss the physical vibrations from the IB. There is excellent dynamic range on most material.

More later:

The new cable quickly turned up in the post but, exactly as I feared, the 2.5mm microjack body would not fit. It measured exactly 10mm in diameter when I really needed a maximum of 9mm. Beggars can't be choosers!

Being solid plastic, the plug body responded readily to abrasion. I chose to use my lathe to reduce the forward part of the major diameter concentrically but finished off the rear half with files and emery sticks. Anybody without a lathe chuck could hold the plug body in the chuck of a drill. NOTE: NOT THE TIP!

I kept the majority of the cable in the supplied bag to keep it clean while I worked on carefully making the 2.5mm micro-jack plug body smaller. I was very careful to avoid damage to the plug's conductive tip.Notice how the diameter at the tip is reduced via a taper. This would not survive much in the way of physical force.

Careful examination of the headphone socket suggests two raised plug location ridges may cause trouble if the plug body is still oversized for the space available. These ridges align the original triangular plug body which has matching grooves. It might be well worth providing two flat on opposite sides to avoid the ridges interfering with the entry of the new plug. I just filed a flat on either side of the plug body after reducing it to 9mm nominal diameter.

Once brought safely down to 9mm over its entire length the plug needed to be pressed gently into the bottom of the space where the triangular part of the Sennheiser plug body normally sits.

Only when it was parallel with the socket could I push the plug gently home. I have made no real effort to smarten op the (now smaller) plug body since it is almost invisible when fitted into the headphones. Most of the body length is hidden in the 9mm deep plug socket in the headphone body.

Do NOT attempt to fit a plug larger than  9mm diameter or you may well break off the plug tip as it will certainly enter the socket askew! How could it be otherwise? You may even crack the headphone's own moulding! Do NOT use force! The plug body must press effortlessly right into the bottom of the moulded cut-out groove first. Only then can it be pushed safely forwards into the headphone micro-jack socket itself.

Any tilting of the plug will surely lead to a flood of tears! Any tightness between the new plug and the Sennheiser body will make removal of the plug and cable very difficult indeed. Patience in reducing the plug to under 9mm will be rewarded.

Do not blame me for your inadequacy if you break anything! Anybody who needs an ambulance chaser to protect themselves from their own drooling idiocy probably needs a wet nurse. Not a sympathetic jury of similar inadequates. All wishing they had won the court lottery themselves without ever lifting a finger.

Talking of which: Flicking the new cable with my finger nail produces no sound in the headphones. So microphony is certainly not an issue. How much current is the cable being asked to carry? Not enough to worry about resistance, impedance or capacitance. Nor any of the other half-understood techno-babble underpinning your desire to expend more money than strictly necessary. I paid roughly £4/ 40DKK/ $6.50 for my shiny new, adapter cable online.

So far I can detect no difference in sound quality using the "cheapo" cable. Why would it be otherwise? The headphones now feel quite lightweight and are much more comfortable. I no longer need to fiddle constantly with the ear cups trying to take some of the excess weight of the original cable off the headband. I have even been able to discard the hat which I was using to protect my scalp from the pressure of the original cable via the headband. I have worn the headphones for hours now without discomfort or the previous distress.

The degree of isolation from the closed back design is perfect for domestic use. The Sennheiser HD-380 Pros have plenty of rhythm and no obvious vices! Their non-tiring clarity means that I am hearing backing singers and instruments I never knew existed on tracks I have enjoyed for decades. The HD-380s  seem to excel with all kinds of music from electric folk to rock to classical. The fine separation of sound sources across the soundfield is remarkable. Percussion is particularly well rendered. Highly recommended as a candidate for your own perusal! Though only IMO, of course.

Update: I had excellent feedback from Sennheiser's Danish office to my email tirade about the heavy coiled cable. They even promised to consider offering a lighter cable as an option for those who would prefer it. I reiterated my emphasis on the need for a closed back headphone for those who do not enjoy total background silence while listening to music. This made the HD-380 Pro an excellent option for those with families. Or even bus and train commuters.(But NOT cyclists!) Open backed headphones are a scourge for those who are only "enjoying" the leakage from the original performance!

I won't hold my breath on the lighter cable option. Particularly since an adaptor cable is so easily arranged at very low cost. While it may offend the purists, a 2.5- 3.5mm solid adaptor and a mini-jack to mini-jack straight cable would do. Does the extra contact surface of an adaptor ruin the sound of a good headphone? Most seem to need at least one and few would go to the trouble of hard wiring their phones to the equipment. The HD-380 comes with a screw-on adaptor which adds another contact even if the larger jack plug provides greater surface area for a contact in the equipment socket.

Searching online suggests that all-metal micro and mini-plugs are available with much slimmer bodies than the cheap plastic type which I used. The only potential problem here is that the entire length of the plug needs to be slightly smaller than 9mm to fit the cut-out in the headphone earpiece casing. Not forgetting an allowance for the plug location grooves.

I looked into a TV/electronics chain store yesterday and saw a number of cables with much smaller diameter, plastic bodied plugs. Prices were no different from those I paid online. So just looking around locally may save some "waist reduction" of oversized plugs.

Click on any image for an enlargement-



It ain't easy being an Onkyo TX-NR818 owner!

For years I had been using an old 5.1 three channel, Yamaha DSP-E800 processor with only centre and surround channels of amplification. Bought secondhand from a member of an AV forum it was already outdated long before I had it safely in the rack. I used an even older Pre-PS-Power, Naim stereo system for the Main/Stereo speaker channels.

The recent arrival of the Sony BDP-S790 finally stirred me into seeking a modern, multichannel AVR with all the latest bells and whistles. It seemed pointless to continue to persevere with the old Yamaha now that I had a better source. I obtained a display model of the Onkyo TX-NR818 for a good price just as next year's model was released. The '818 had supposedly much better equalisation than its '828 replacement, according to all the AV forums. So the older one was the model to get. Though even there Onkyo was cost-cutting by paralleling the twin subwoofer sockets internally. Only their high(er) end models allowed individual subwoofer equalisation.

Here's a link to a really excellent series of illustrations of the TX- NR818 inside and out:


Click on any image for an enlargement. Scroll to move between the enlargements. Back click to return here.

As the '818 had a built-in crossover I was now able to remove the inexpensive but ailing Behringer CX2310 digital crossover from the rack. Its channel muting push switches were getting extremely unreliable. So I was glad to take it out of the system. As I no longer needed to split the subwoofer from the Mains channels this also meant I could also remove the Behringer mixer. This had been used to feed LFE back into the IB subwoofer channels from the old Yamaha processor.

Adding LFE had dramatically improved the impact of my original system. Running subwoofers simply by dividing the Front Mains/Stereo speaker channels is fine for music but robs films of any impact at all. No matter how loud I set the subwoofers relative to the speakers it was still completely gutless. I spent several years wasting my time with no LFE before realising my silly mistake. DTS films were far better than Dolby due a technical problem in the Dolby processing when down-mixing to stereo. Unfortunately, not all hired films offered DTS.

Now the brand new NR818 seemed to suffer from exactly the same lack of impact! I ran the Audyssey MultEQ XT32 Room Correction and Speaker Setup a number of times without getting remotely satisfactory bass on films. Music was fine and even seemed an improvement over the previous system. Forum members suggested raising, lowering and even removing the subwoofers entirely during the Audyssey set-up routines. I tried them all with completely different results. It probably doesn't help that I am using an attic as my AV room. Audyssey is probably as confused as I am without parallel walls to work with!

On films I was still suffering from a complete lack of impact. I even asked on the AV forums if anybody else had similar problems. It seems that Audyssey produces a flat response which many AV fans find rather anaemic. I had also removed the BFD subwoofer equalisation which didn't help. So reluctantly I brought back the BFD and sat it on top of the Behringer EP2500 subwoofer amplifier out in the IB enclosure.

The BFD provides the vital boost to turn the old, substandard  AEIB15s into real subwoofer drivers rather than mere woofers. With a measured Fs of 32.5Hz and very stiff suspension they just can't do deep bass no matter how I turn up the volume. With the BFD adding +16dB @ 20Hz spread over 2 octaves the older drivers are worth having. Without the BFD boost they are not!

The BFD certainly livened up film watching but the system still lacked any real impact. I tried adjusting the LFE level, bass level and all the other potential impact improvers in the endless menus. I removed all the optional inhibitors to dynamic range. Or at least I hoped I had. Things did improve but it was a very slow process involving lots of trial and error. The problem is the vast array of menus and options and the completely unforeseen effects they sometimes have by default. Despite over 5 decades of hands-on, Hi-Fi/AV enthusiasm I still found myself struggling to understand what half the menu options meant! My guesses were probably wide of the mark.

I was still unsure at this point whether I had the BDP-S790 correctly set to optimise my results. It was an incredibly steep learning curve to be suddenly faced with non-working Wireless system, a brand new and complex BDP menu system and remote. Then the new and even more daunting and far more complex AVR all at the same time!

It didn't help that my wife kept saying the sound quality was complete crap. I actually value my wife's input because she has better hearing than I have after my decades of exposure to industrial, building construction, rock concert and domestic AV noise. Not to mention the ownership of a noisy sports car and unprotected target shooting in my youth. It all adds up as one ages! Pardon?

I had already taken the Naim boxes out of the system. In a desperate attempt to try and improve the SQ I fitted the old Naim NAP180 back in to drive the Main/Stereo speakers. It required I order a special cable from the UK and I still I can't say it was night and day improvement, but it can't have done any harm. Can it?

Films are slowly regaining their impact but it remains a real problem to hear the dialogue. Both of us notice it. I keep turning up the Centre speaker to avoid the music drowning out the dialogue. It helps but it was never a problem hearing the dialogue with the old Yamaha. I'm still using the same Centre speaker. An old Mission 750C to match the 750F Mains.

The Sony S790 is a great improvement on the Pioneer LX70A. How could it be otherwise? I rather like the brighter sound of the Onkyo AVR over the old Yamaha. I now listen to music via All Channels Stereo. It adds air and space even if it is completely wrong from a hifi purist point of view. I often click around the endless soundfield options but always come back to ACS. The new system sounds better on classical organ music as well. There is no real directionality in an organ recital so why worry about the "purer" stereo options?

One month on and film impact is still relatively poor compared with before the arrival of the TX-NR818. Dialogue clarity and intelligibility remains a serious issue. Perhaps the Naim power amp should be moved to the Centre channel? After several failed experiments I can now get fairly decent sound on satellite TV. Using TV Logic and adjusting the levels of various channels and the subwoofers helped. Attempts to use film sound programmes produced very poor results.

VITAL INFORMATION: Check whether DRC is set to Auto or on in your BDP/DVDP menus!
Poor film dynamics is a sure sign of having overlooked this default choice on a BDP/DVDP setting!
DRC is there to protect TV speakers and sound bars.
Not for those with serious speaker/subwoofer systems!
I could not believe that "Auto" would be selecting heavy DRC by default.
I was blaming the NR818!


Some thoughts on constructing IB baffle walls

It came as a surprise to realise that somebody was actually listening when I suggested concrete lintels to mass load and stiffen an (IB) baffle wall. They certainly make for clean, strong, stiff and dense units for incorporation into a stud wall. Though certainly heavy they only have to be handled once and are not usually beyond the strength of a pair of most adults. The same could be partially said for bricks or (dense) concrete blocks for introducing mass though these offer no stiffness to the construction. It would be rather pointless to try using lightweight blocks unless they were bonded together into a complete block wall of sufficient thickness to be stiff enough in its own right.

I don't intend to discuss stud, baffle walls very much because they are not usually stiff enough in normal domestic thicknesses. (4" or even 6" /100-150mm) Adding two layers of plasterboard cladding doesn't add much stiffness to such a flexible structure. Only a little extra mass. Which is neither here nor there when driven by a decent number of large IB drivers to normal levels. I might consider a stud wall using 8" x 2" studs but this raises the cost significantly. Finding suitably straight lengths of timber in this size for an entire baffle wall might prove frustrating. Not least for your supplier as you pick and choose from his twisted and wavy stock! Leaving only the unsaleable lengths for the poor devils who follow in your path. Sawn finish, structural rafters or joists may not be what you were hoping for.

It seems to me that stud walls are only really stiff in the vertical plane. They can flex fairly freely across the width of the wall despite all the noggins and the ceiling and floor plates along the top and bottom. You could think of a stud wall as corrugated cardboard set up with the corrugations vertical. Easy to roll up one way but much more difficult "across the grain."

The greatest resistance to bending is from top to bottom. Not least because the wall height is usually the smaller dimension compared with its width. The wall could still "balloon" overall under the reciprocating driver reaction forces and/or pressure effects. Remember that a large surface needs to move by only a very tiny amount to undo all the careful design of our relatively small drivers.

Such movement can be additive or subtractive from the driver's own output. In or out of phase with what the driver cone is doing makes little difference in the grand scheme of things. All baffle wall movement is bad! Not least because it usually affects the frequency response. It may also rob the reproduced sound of serious impact. Some people make quite a good living providing sound absorbers not too dissimilar to a normal stud wall in flexibility and absorption.  

One answer to this flexibility problem might be to adopt sheet covered crate style boxes. A simplified, honeycomb structure raised on steroids! Laminations of sheet material over boxes are used for everything from humble flush house doors to ultra high tech aerospace materials and even the world's largest wooden structure. Search for Seville Metropol Parasol to get an idea of the possibilities. See link below:


In the case of our more humble Infinite Baffle wall you could  imagine a very large, letter sorting frame. One stretching from floor to ceiling and wall to wall. Covered both sides with stiff sheet material all glued firmly in place. The box sides would be formed by using interlocking halving joints along the lengths of suitable strips of stiff material to the desired depth (thickness) of the baffle wall. I'll stick my neck out and suggest at least an 8" /20cm thick without any real mathematical basis. It just seems about right as a rough minimum to ensure success.

Links to images of halving joints:



A circular saw or router and cutting jig would greatly aid accuracy and ease of construction. A carbide tipped blade or bit would be most sensible to cope with working in abrasive sheet materials. A degree of freedom at the joint cut slots would greatly aid gluing and construction provided it was not overdone. Cutting the sheets into strips is best left to the supplier if they can be absolutely trusted to make straight lines.

MDF, plywood and OSB would all make suitable and affordable building materials for indoor use. Since the sheet material is used to build a rather thick wall its flexibility across its own thickness becomes almost secondary. High mass is still desirable though. Probably suggesting MDF, as the leading candidate. This material is more readily available in larger sheets than plywood in my own experience.

I seem to remember 10' x 6' could be obtained without too much effort. Though these sizes are not absolutely essential since sub-modules of boxes could be built up and each module glued edge to edge to produce a much larger overall area. The natural doubling at the edges of the smaller modules would add some mass and local stiffness. Building sub-modules of a manageable number of boxes into a vertical wall is far easier than raising the entire baffle wall from the floor!

Though there are affordable winches if you really fancy your luck. Naturally you will only raise the empty box structure. Cladding, mass loading and installing the heavy drivers comes later. You'd also need to study the geometry of deep rectangles as they rotate. The radius travelled by diagonal between bottom inside and top outside edges is much larger than the physical height of the wall! You are going to have to allow for this by making your structure a bit shorter. Then add ceiling packing once you have the whole thing upright.

If made to suitable sizes then the boxes could be mass loaded with size-matching bricks, paving slabs or concrete blocks. Or even very strong or multiple nested bags of dry sand. The apertures for the drivers should be left open on both sides of course. While depth is highly desirable in the sides of the boxes for both strength and stiffness the driver apertures do not want to be too enclosing. Otherwise the drivers cannot breathe easily.

Colouration is probably unlikely given the IB's frequency bandwidth and the relatively modest size of the likely box dimensions. Though it may still work against the desire to build a free-breathing array. The IB manifold is rarely attacked for its introduction of colouration. But perhaps we should set higher standards of driver clearance for an array? Or why build an array in the first place? Very thick baffles around the driver will choke off the freedom to breathe incorporated into the usually slender, cast baskets in even the largest of modern drivers.

The driver apertures do not need to be the exact module size for our intended reinforcing boxes. Though this ought to be born in mind. Through apertures could be made by leaving out (say) 2x2 box sections from the wall structure. Though I would hesitate to allow a tall empty slot in the structure for a vertical array without intervening structural "shelves" between each driver.

The really ambitious (and skilful?) builder might even incorporate curvature into the intended baffle wall. Not necessarily an overall bending but a gentle thickening at the centre to add greater stiffness or visual drama. The structure still has to be covered in plywood. Or one's alternative choice of surfacing material. Extremes of curvature would require more flexible covering materials. Stiff sheet materials do not readily lend themselves to curvature in two planes! Though smaller sheets are rather more accommodating.

The downside with a box core structure is the difficulty of adding concrete lintels. Bricks or blocks would need local fastening, wedging or bonding to avoid isolation from the overall structure. Finding and curing a rattle between bricks or blocks after the surface material was fixed in place could be a nightmare!

The box structure itself might offer decorative potential to the imaginative builder. It may be that the wall itself would be stiff enough without its dual surface sheeting. The structure could be clad on the rear only to achieve airtightness, for example. Leaving the front open to the application of translucent or transparent material. Or even completely open to be used for storage and/or lighting effects. One must hope that one's vast collection of BluRay disks and CDs do not themselves rattle when stored in such a structure!

Early aeroplanes used doped fabric to achieve remarkable stiffness. As do model makers using a variety of thin materials fixed over otherwise weak balsa or thin plywood structures. Providing the baffle wall is still reasonably airtight the possibilities are endless. One might even imagine a series or pattern of boxes being covered on only one side or only the other. Perhaps to provide storage on both sides of the wall without a continuous cover on either but still remaining airtight.

These suggestions are only for further examination in the real world of building baffle walls. I offer no guarantees (whatsoever) that any of them will work in practice. Not even with careful thought, design and construction.



Bløødy wire-less!

The arrival of the Sony BDP brought unexpected potential to join the 21st century. Not least wireless. Or rather wire-less in my case. I had no wireless router to play with. I was still in fixed PC mode. I had no real need for an expensive laptop with their dinky little screens, poor battery life and inferior performance.

Moreover, a smaller screen would be worthless to me unless I upgraded my reading glasses by a couple of dioptres.  The 24" screen on my PC is fine with only +1 dioptre at arm's length. Reading a book or paper needs a +1.5 prescription and good light.

Like many of my age I am a martyr to lack of accommodation. And I'm not referring to my modest rural cottage. For the majority of us, the lenses in our eyes harden with age until expensive vari-focals are necessary to cope with the growing fuzziness at close range. Ironically, my distance vision has improved to allow driving glasses to be only a very distant memory. I put this down to spending countless hours out of doors (cycling and walking) instead of being cooped up, like a rabbit,  inside buildings.

But I digress:

I went to the city and bought a wireless router and a wireless USB dongle. It didn't work! I tried everything I could think of. I searched endlessly for solutions online. Literally dozens of hours of my rapidly passing life were wasted. Nothing helped. So I bought another USB wireless dongle. That didn't work either! I was a very unhappy bunny!

Frustration at the lack of progress was making me increasingly angry. I was getting more and more paranoid to the point of giving up and taking it all back for a refund. I even started a formal case with the router maker's technical help line. Over a week later I hadn't made the slightest progress! Not one step forwards.

Meanwhile the seemingly pointless search continued online until... finally... I came across a couple of posts on an online forum. It seemed my very popular and well respected firewall was to blame for all my wire-less troubles. I uninstalled it and I had a wireless connection within seconds at the first attempt!

The sickening point of all this wasted time is that the router maker knew there was a long term problem with Zone Alarm firewall blocking their wireless connections. But hadn't said a word to me about it. There is no remedy except to uninstall ZA. Naturally I left my opinion of the router maker's service review website. These businesses are always keen on reviews. Much less keen on the simple truth.

The Sony BDP now had active functions with online music and video readily available. I played with these for a while but my computer could do much the same with much less effort. More importantly I didn't need to sit within sight of an active TV screen just to be able to find my way around the menus and services. I have no use for, nor yet own, a smart phone. So haven't that obvious route available to me.

Having wireless and a much reduced box count on my AV rack made me think. The latest AVRs had wireless too. What did that mean in the context of my near-obsolescent AV system? I had better find out! I started searching the online forums for suitable candidates. One particular AVR seemed to excite the attention of forum members to the tune of hundreds of pages of mostly repetitive discussion: The Onkyo TX-NR818. I was hooked. The poor old Yamaha's days were numbered. As were the Behringer boxes. Or so I hoped.



Do all boxes of electronics sound alike?

I have started writing my blog again for purely selfish reasons: The stimulus it brings to my own life. Retirement is one of the most dangerous pastimes on the planet. It is usually fatal. If dementia doesn't get you in the end then depression probably will. Exercising your mind is the best way to avoid mental obesity and sloth. 

I now think of my blogs as diaries. left lying carelessly around, to be read or rejected at a whim by others. I do not need your approval. Nor your respect. Nor am I (remotely) trying to impress anybody else. This does not mean that I do not set some minimum standards for my monologues.  

I have no other justification for my blogging on this subject other than having followed the hobby of hifi (and later AV) since childhood. My father loved music and built loudspeakers and enjoyed his music via a valve powered, Armstrong tuner amplifier and Philips reel to reel tape recorder. That was many years ago now and the electronics industry has grown vast over the intervening decades. This has cost me (and many others) far more than was strictly necessary for the simple enjoyment of reproduced music. 

But, the exercise has brought considerable enjoyment in the ownership and use of their products. Not to mention the countless wasted hours spent trying to improve my system from a subjective viewpoint. Most importantly I have learned to change my mind as often as necessary to maintain my pseudo-scientific standards. I have repeatedly gone from raving hifi subjective fundamentalist to blind testing disciple and back again without the least sense of guilt. One should always remember that it is only a hobby unless you are making serious money from this daft pastime.   

I also get great pleasure from the music itself and enjoy sharing my thoughts and ideas about its reproduction. Though I have absolutely no illusions about my skills or wisdom in this field I do have considerable experience in building and using the kit at a fairly basic level. If you find my blog uninteresting then start a blog of your own! Your own thoughts are equally worth sharing as long as you do not demand automatic respect for your ideas. Solomon would never have fallen for the hype of hifi sales so don't expect (any) real wisdom from the so-called gurus. 

Old age teaches us that life quite literally has absolutely no meaning. Other than what we make of it during our brief abuse of space, resources and time on this tiny planet. One insignificant planet amongst countless billions of others. Do you really think your set of ideas, values and morals is somehow superior to those of anybody else in the universe? Or even in your own street? Dream on! The tramp you just studiously ignored may well have an IQ above 140. 

I never thought I'd add anything to my IB blog again. Then my overpriced, over-hyped, overweight, Blu-ray player, the Pioneer LX70A, did me an enormous favour and formally retired. "No disk!" Hoo-bløødy-ray!

The damned thing had always been extremely over-sensitive to the quality, cleanliness and copy protection of any disk it was ever asked to play. It took forever to load. [Several minutes!] If it grudgingly decided to play anything at all. It sounded no better (nor even different) than my ancient, secondhand, CD63SE Marantz CD player from another era. There is a lesson for us all here. All boxes sound the same unless they are sold by Aldi supermarket. Or do they?

The LX70A used the most oblique and frustrating method of firmware updating ever invented by arrogant, pen-pushing, pedantic, tie-owning jobsworths. i.e. Those who have risen far beyond their allotted station in life:

An "image" of the software file had to be burnt onto a pristine, new, recordable CD. Which was then inserted into the gaping maw of the basking shark of the BDP world. Where it would whirr and rumble like it always did when playing any disk. The Pioneer was the Harley Davidson of the BDPs without any of the desirable traits. It needed no subwoofer to make a decent racket. It could manage pink noise with one hand behind its back and the rest of the system switched off! It was as if somebody in the vast hype department at Pioneer decided a silent BDP would short-change the new owner. So they added lots of mechanical noise.

The damned thing chugged on like some sulking, obese teenager well beyond its useful purpose. Playing only common or garden hired DVDs with difficulty. It would have nothing to do with rented Blu-ray disks. Firmware updates finally dried up in 2011. So its built-in obsolescence counter started ticking down to the arrival of the eagerly anticipated, grim reaper.

My very first purchased Blu-rays discs would not even play in the damned thing until I had updated the firmware! With all the unnecessary palaver that entailed. Involving downloading new and unknown software and buying  new pack of disks the next day. When I had really, really hoped to relax in expectation of being able to enjoy my new and very expensive toy on the same evening of my birthday! Thank you Pioneer!

I can't bring myself to show another image of the damned thing so you'll have to make do with a link:


All in all, the LX70A was a moody, lumbering, temperamental, inarticulate, bulky, overweight, bullying tortoise living in the clouds with absolutely no saving graces. It's no wonder Japan is going down the tubes if this is their idea of high end AV quality and customer service!

They showed bugger-all respect for me as a consumer of their obscenely over-hyped nonsense. I have duly added Pioneer to my list of  Chinese box re-labellers and movers with whom I will have no more truck. They probably won't notice my absence from the endless queues around the block to purchase their latest goods.

I tend to buy this sort of stuff only rarely. Relying on spending a bit more each time in the hope of getting decades worth of life out of it. Usually my strategy works. Until I fell for Pioneer's less than subtle clap crap trap.

The routine of enjoying films had come to such an abrupt halt that something had to be done. Our Saturday evenings would be dull affairs indeed without a new hired film to watch. It's not as if the TV companies care about anybody with an IQ measured in more than a few digits above their own "educationally-challenged" "Arts" imbecility.

Neither of us is much interested in film replays except at very long intervals between viewings. (Counted in years!) Our modest library of DVDs and far fewer Blu-rays mostly collects dust. So, after a swift look at consumer reviews online, a Sony BDP-S790 was duly purchased. Without the bulky Pioneer and CD63SE bulking out our chest-high rack it looked practically empty at the top end with the skinny little Sony in place.

The Sony whines.  Of course it whines! They said so on the AV forums that theirs whine too! I spoke about this to the dealer at the time of purchase as a bit of a worry. We do live in a rural situation with very low noise floors. Of course he denied any known problem with unwanted noise from this player.

How long has Sony been making electronics? Slightly longer than I have been officially registered as belonging on the third rock from the sun. Still the BDP-S790 whines. It's has a Sony label! Deal with it!

Call me biased (deluded?) but for a while I thought the Sony sounded better than the Pioneer or CD63SE. I had left it playing an organ CD while I browsed off-stage right. Suddenly, somewhere in the background, I noticed new nuances in the bass. A new tune was being played on the organ pedals.

Normally this means dragging the CD63SE out from storage to make A/B comparisons. A tedious procedure involving severe concentration as the same bit of music is repeatedly churned out like some tasteless spaghetti. Best not to go there! Save it for a boring Sunday afternoon, if you really must.

If noticing differences in SQ involves repeated plays and intense concentration then surely the game is already up? Every box of electronics must sound exactly the same. Except that some don't whine and some don't rumble. Choose your expensive toys relying entirely on superstition and appearance alone and you only need a new one when it dies two or three years down the road. It's called consumerism with built-in obsolescence. If a thing really was better then it would be easily noticeable. If it sounded the same then without the hard sell hype nobody would need a new one. Unless it had miraculously stopped working. Factories would close. Suicide rates amongst big (and small) spenders would increase. Though the world would continue to turn.

Your supposed skill in choosing toys is a total illusion fostered by a vast and totally corrupt, global industry. One based on lies and dedicated to making every box sound less worse than all the others. That really takes some doing! But, each new box must appear subtly, cosmetically different enough to be interesting to the idiot buyer. Your collection of expensive boxes just means more ornaments with volume controls or on-off switches. No more and no less.

Not convinced? Then do your own homework online about A/B/X and blind listening tests. There is plenty of reading matter out there. I did my own test decades ago with an expensive record clamp. I was convinced it added enormously to my listening pleasure and could describe the clear differences to myself in glowing detail. Until, that is,  my wife ran a blind listening test and I was completely unable to discern any difference. Similar results followed with cables. If I couldn't hear any difference, despite my previous decades of attentive listening to a wide variety of systems, then something was definitely amiss.

The purchase of a Linn Sondek repeated the bleeding obvious: My Thorens turntable deck was not noticeably inferior. Nor really any better. No amount of expensive dealer set-up, new springs, motors, bearings and power supplies made the slightest difference. Except to my wallet and that of the dealer.

Speakers and subwoofers do still sound different even to my (supposedly) cloth ears. I don't like the sound of many of them. To bright, too aggressive or simply attention seeking. Many of them seem unable to make my foot tap. This is the only test I know for true enjoyment of any sound system. I rediscovered it in the hallway of a large hotel during a "High End" AV sales drive/exposition.

I sat there for ages listening to a budget system bouncing along on music I had never heard before and very unlikely to actually want to purchase. In between sessions I dutifully did the rounds of the all the expensively hired rooms and listened to the "arm and a leg" systems on their carefully set up stands. Often with cables which cost more than some new cars. They certainly all did "hifi" in the usual way, but had no sense of pace or rhythm. No excitement. No desire to hear another track or actually go out and buy the demo CD.

It was always played very loud. Always impressively so. Have you noticed that? The very "high end" rooms were always the worst. They actually sounded rather dire. I would listen for a few moments and then have to leave the room for fear of laughing out loud! If I stayed it was only on my own terms. I would sit there desperately trying to like the sound. And equally desperately trying to tap my foot in time with the deafening roar happening somewhere up front. I would swap seats as other became bored too. It never helped.

So I'd return to the cheapo system playing in the hallway and enjoy another refreshing dose of music against a background of café chatter and rattling coffee cups. Somehow that system played real music through quality shoebox speakers. Not perfectly and not particularly loudly but it held my attention and my feet were locked firmly in step with the performers. Perhaps systems do sound different?

I know mine always did when I finally got home tired and usually a bit head-achy. It was like having warmed wine poured gently over me as the first few strands of music washed over me. With every subtle detail and emotion of the music laid bare. And, I could tap my foot unhesitatingly. Even to the slow movement of a choir, orchestra or organ. I'll swap bounce for loud any day. I can do loud just like the demo rooms but value my few remaining years without the compete loss of my hearing. Pardon?

Next time somebody is trying to sell you some black audio box, or other,  ask them to turn the volume down. Still impressed? Thought not. ;-)

Lacking musical inspiration? Try "Celtic Circle 2." My wife hates it for the number of times I have listened to it. Somehow it crystallises everything I like about Celtic music. Disk 1 and 3 aren't bad either. Though the sound quality is not remotely on a par with original artist's CDs. There, still believe I have cloth ears? CDs sound far more different than expensive AV boxes? You'd better believe it! ;-)

Vitally important SQ Note: 

The S790 reverts to DRC (Dynamic Range Compression) by default if you set it to Auto!

Fine if you just want to use your TV speakers or even a sound bar which need such protection.

For any serious speaker/subwoofer surround system you should set the S790 DRC to OFF in the menus! 




I have decided to republish my IB blog. A humour failure is no excuse not to give others a chance to achieve a serious upgrade in their sound quality. The rambling format is not conducive to finding a quick answer to everything. Or anything at all, for that matter. Perhaps this is the point? A hobby is supposed to kill time productively. Rather than the valuable time of others destructively. I put in the time so you can cut out the middle man. You can safely ignore everything you read here and go straight to the source: (Mentioned below)

I have spent far too much money over the years on Hi-fi. Endlessly searching for mere nuances. When if the truth were known most boxes of electronics sound exactly the same.

The IB subwoofer was easily the most serious and clearly audible upgrade in sound quality in nearly five decades of making an unnecessary mess at home.

Rule 1. Use all the same drivers in your IB and get them from a reliable source. Most of my original IB problems were due to being sold crap drivers and my total inexperience with the IB concept. There were no IB Cult FAQs back then.

My first four AE 15" drivers were so far off spec (and cosmetic acceptability) that I am still amazed that the manufacturer had the nerve to remain in business.

All four, straight taper, vinyl coned drivers actually have a measured Fs:32.5Hz instead of the claimed 16Hz. God only knows what the other specs look like in reality! The maker repeatedly denied there was anything wrong with these drivers on the AV forums.

Early model AEIB15 backplate. I was so ashamed of these that I have never published any pictures of them until now. I still have no idea why I have protected a company which would let these out of the factory door! If I'd made these myself I'd have thrown a tarpaulin over the scrap bin in case anybody ever saw them! 

His offer to replace them, free of charge, with the new model, was both very costly and frustrating. And, they still did not match the claimed specs! Though at least they erred on the right side of useful the second time around. Fs:13Hz instead of the still claimed 16Hz. The cosmetics were considerably improved too. It could hardly have been otherwise!

I probably learned far more from my struggle to tame the originals than I might have done had they actually been remotely to the published specs. That does not make me remotely grateful! Why should I be grateful for paying for quality and receiving crap quality drivers?

They (the older 32Hz plastic-coned drivers) only remain in use now because they complement the compromises of the newer drivers and add some free cone acreage. The newer AEIB15 drivers roll off very early and steeply above their peak output with a very narrow, useful power band. Which would  normally require a very low crossover point and huge main speakers. While the older drivers roll off very early in the deep bass unless massively boosted low down. I'm talking +16dB @20Hz, two octaves BW of boost from a Behringer DSP1124 Feedback Destroyer! Yet, together, somehow, these very different sets of drivers eventually learned to play together. It took me quite literally ages (years) to get the balance right.

I see the AEIB15 is now being listed again, at twice the original price, after a long hiatus. I wonder what the "real world" TS parameters are this time around? Given that you can buy an 18" from Fi for less money the new AE drivers are not quite the bargain they once were. One 18" Fi IB318 driver moves twice the air of the AEIB15. Making the Fi driver an even better bargain. You can get away with two Fi 18" instead of four AE 15" to make an IB. For the same money you can move huge volumes of air with 4 x IB318s.. You do the maths.

Rule 2: Never (ever) underestimate reaction forces from a row of large drivers in a flimsy structure! Ignore the knuckle-dragging ignoramuses who say a cone has no mass to speak of. They forget the huge mass of air involved and its resistance to violent acceleration and deceleration. Just build an opposed driver manifold first time round and do yourself an enormous personal favour.

Rule 2 (Get-out clause b) If you have a solid concrete or brick screen wall and you can cut holes in that for your drivers then you can safely ignore Rule 2 as well.

Rule 3,4,5-100. Don't think that you can get away without adding LFE for your film enjoyment. Adding a subwoofer to enjoy music is fine. When watching films it is utterly hopeless to just split the Main speaker channels with an active crossover to obtain a bass signal for your IB. I spent years wondering why my IB didn't thunder until I finally added LFE.

If you feel you have any pressing questions on IB subwoofers then consult the Cult of the Infinitely Baffled forum. You could do worse than read the copious FAQs first. Or at least pretend you have before posting:

"[It is] better to be thought a fool than to speak out and remove all doubt."
(A corruption of some fictional, biblical nonsense, usually attributed to plagiarism by Lincoln or Twain)

I think you will find the contents of this blog are ample proof of the above sentiment.

I have my own saying:

"Better a failed clown than a successful bore."  

I seem to have spent a lifetime trying to perfect the latter. Imitate me at your own peril!

Keep smiling. Somebody might need one more than you can possibly imagine.