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

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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-

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

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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:

http://onkyosound.blogspot.dk/2012/08/bild-vergleich-onkyo-tx-nr-809-und-tx.html

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!

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Some thoughts on constructing IB baffle walls

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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:

http://inhabitat.com/metropol-parasol-the-worlds-largest-wooden-structure-opens-in-seville/metropolparasol1/?extend=1

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:

http://www.raygirling.com/images/cab06.gif

http://www.raygirling.com/images/cab07.gif

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.

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