Punchy bass

[Glue]

In many forums I have found some strange deviation of posts who end up in this one or the other direction.
Mostly for some "regulars" glueing their asses (assets?) to their `domain`- BEING RIGHT and SAYING IT
Well well well
To give my opinion to punchy bass I have found after building a lot of small and larger speakers trying to max out bass performance without `loosing it`is that closed cabinets are so much more capable of being punchy.
Yes, modern speaker designs have improved a lot from the 50`s and 60`s designs as they could be smaller ...
But I generally found a different `culprit`!
To me it rather depends on the `stuffing` that is either
1) too much
2) too less
3) too poor in quality
4) too old
or simply unsuitable for the task .

[VantheMan]

Hi Glue, One of my ears is named after you.

Anyway, how does one know if one has too much stuffing or too little and what in your opinion is the best stuffing to use. I followed the kit instructions for my wd25TEx closed boxes which seemed to me perhaps too little but coming from ported Hb2s full to the brim with acoustic foam, what would I know.

Chris

[petercom]

Let me try and put this all into perspective...

After decades of designing commercial loudspeakers I, and other designers, have found that most people want bass that packs a wallop. As speakers increase in price, the requirement for 'bass in your face' tends to reduce if only because one is dealing with a more sophisticated and knowledgeable customer PLUS the speaker designs are bigger, which helps.

So, when I designed the Heybrook HB2, one of the targets we set for ourselves was a response that extended down to 40Hz to reveal the fundamentals of bass guitar, piano and so forth. This was only possible in such a small cabinet by using a bass reflex design. I avoided the usual bloated bass by designing a port with a modicum of air resistance at its entry point, thus lowering the Q.

However, I still remembered the enjoyment I heard from the speakers I home built in my teens which were in large closed boxes. I had also been intrigued by selling Scandyna A25 speakers which had much of the same performance but in smaller cabinets.

So, for WD25 and WD25T, I wanted to explore the Aperiodic design of the Scandynas. For those that don't know, Aperiodic is a compromise between the low Q of a correctly designed sealed box and the greater low frequency efficiency of bass reflex. It is something like a ported box with a high resistance in the port.

Aperiodic loading, to work well, does require a bass driver with a specific arrangement of Qes and Qms. I worked with SEAS, who had originally designed the Scandyna drivers, to make a modern equivalent.

The WD25T has the benefit of a large sealed enclosure with the internal damping provided by an aperiodic connection between two internal chambers which break up the usual vertical resonance modes of a tower speaker.

As for internal damping materials and quality, there are two different requirements. The first is to absorb mid to high frequency reflections inside the enclosure from the cabinet walls. This is probably best arranged by a lining of acoustic foam or very thick felt. In a sealed enclosure it is also beneficial to provide a loose filling of a long fibre material, like wool, to provide some resistance and mass loading to control the system Q and marginally lower Fs.

With all loudspeakers the positioning and amount of internal damping can be arranged and adjusted to taste. The designs for WD25 and WD25T were made to provide a very analytical and even bass response, using the wall behind the speakers to optimise the bass power for the room acoustics (see Roy Allison et al).

Generally what you will hear, especially from WD25T, is exactly what is on the recording modified, of course, by how your hi-fi equipment is performing. I'm particularly pleased that VantheMan managed to get his amplifier to deliver the required results.

[Baggy Trousers]

Originally Posted by petercom

After decades of designing commercial loudspeakers I, and other designers, have found that most people want bass that packs a wallop. As speakers increase in price, the requirement for 'bass in your face' tends to reduce if only because one is dealing with a more sophisticated and knowledgeable customer PLUS the speaker designs are bigger, which helps.

Lest Peter thinks that his interesting post has gone unread, I thought I would make a few observations in response thereto.

The paragraph I have quoted conveys rather more than is actually said, but it might be thought provocative to pursue this line of thought, so moving right along . . .

What I have found absent from the debates had over the last sixty years, is any particular reference to the type of music which the unit is intended to reproduce. I find this extraordinary. To me, this is a premise fundamental to any argument on the subject and in my view, its exclusion probably has led to more personal disappointments with speaker performances than any other factor; the discussion seems to have been stifled by the acceptance of a pretended "universality" of domestic speaker.

There was a time when the performance of a “full range” driver from the likes of Bakers or Stentorian mounted in a suitable cabinet was considered “state of the then art” and perfectly acceptable for pleasurable listening to any musical genre then extant - it still can be. But this was before the advent of what I might call “manufactured” music, beginning in the ‘fifties. Until that time, instruments organically had evolved and if we confine the discussion to bass performance, (leaving aside the pipe organ, the 64’ register of which goes below 20cps), the bottom line (of polyphony) usually was provided by something barely changed from the classical bass viol, an instrument generating not very low frequencies and of unusually narrow dynamic range, vide the small contribution made by the slap-bass to the earlier rock ‘n’ roll records compared with the power of the modern amplified bass guitar in similar music.

In respect of “pre-manufactured” music, I contend that, generally speaking, these designs remain wholly appropriate in that regard. Nevertheless, it has to be acknowledged that modern houses in size and construction are different from their forebears and in very many instances, it no longer is possible/desirable to accommodate the physical dimensions of a box of yore.

I think, therefore, that a truly “universal” speaker may not be possible, a view shared in a conversation had with the great Dr Dutton a long time ago.

Was it Les Paul who began the “guitar revolution”? Anyway, it is this instrument in its various electronic iterations which has come to dominate the “popular” genre of recorded music and it is the bass guitar with its degree of amplification undreamt of half a century ago which I imagine has so influenced modern speaker design with “in your face bass” being obligatory. I imagine that there is a synergy at work here as modern music is composed/arranged to be compatible with the modern speaker and the modern speaker evolves to accommodate new audio requirements. Reproduction of this "manufactured" material appears to involve large cone excursions and energy consumption which, to me, suggests inefficient air-coupling - I wonder how the likes of Led Zeppelin or Black Sabbath might fare with the 10W amps which were the norm years ago. I might be surprised by their performance since these were man-sized sine wave Watts and not whatever spurious metric is now employed in marketing hype. But as I do not listen to this form of musical entertainment, I am not qualified to offer any worthwhile opinion of speakers manufactured to combine with this genre.

What I can say, however, in respect of "organic" material, is that I have yet to hear a speaker system superior to the best of what was produced years ago for the reproduction of “organic” music, suggesting that since the principal change of the last, say, fifty years is the musical and instrumental composition of source material, a different (or at least substantially altered) type of speaker and enclosure is needed to to cater for this change - a type that is not necessarily compatible with the historical side of things.

My contention is that as with so much else in life, it is a question of horses for courses. I am remarkably fortunate in still owning the superlative front/rear-loaded corner horns I bought in 1967 as well as having the room to house them, but they are getting on for 1500mm tall, quite wide and deep, so I’m dreading the inevitable downsize. Mercifully, a Haydn string quartet is anything but “in your face”, so the "punchy bass" aspect of things does not concern me, but I readily concede that my set-up might prove woefully inadequate for a Who fan.

Which sort of brings me back to Peter’s beginning.

[willslenco]

Very well put Baggy, I would also add that modern contemporary music can also be very complex compared to early contemporary music. To give an example a number of years ago I, along with some other audiophile friends, was auditioning an Ortofon SPU which was absolutely sublime with jazz and simple acoustic tracks etc but when presented by a complex rock track it sounded very muddled and was, in fact, quite unlistenable.

Side note: This is exacerbated by the amount of compression used in modern contemporary music (to make tracks sound more polished by controlling maximum levels and maintaining higher average loudness).

My listening at home is near field and whilst my now weapon of choice is a pair of LS3/5A I sometimes resort to a more modern pair of monitors as the LS3/5A just can't cope with the very low level bass etc and become somewhat 'dead' sounding. The modern monitors I use are either Russell K Red 50 or a pair of prototype Practical Electronics mini monitors voiced a la LS3/5A but using a larger modern bass driver and modern tweeter in a slightly larger enclosure but still with a rather complex crossover (all designed and built by Jake Rothman who has written quite a number of articles on building modern LS3/5A clones.

[Baggy Trousers]

Probably of very little and only peripheral interest to later generations, but I shall add a postscript to my earlier comments anyway.

I mentioned Dr Gilbert F Dutton, an unusually clever man who was Chief Engineer of EMI for a number of years. Incidentally, the "F" stood for "Faraday", so his calling was preordained! He very much shared my view that one speaker was incapable of being all things to all men. For this reason, whilst he was consulting engineer for Abbey Road studios, the recording engineers replaced the Tannoys inhabiting all three studios with 605A Altecs because the former were incapable of satisfactorily handling the demands of the new pop genre which was becoming an increasing element of the Abbey Road diet.

However, for "classical" recordings, new "Gold" Tannoys were retained for monitoring, now in the Lockwood cabinets which I have never thought particularly good, but they were considered superior to the 605As for this type of material, thus demonstrating that different source materials required different means of reproduction. Later, the good doctor produced the EMI RS143 using a 15" Wharfedale and someone else's tweeter which was held in high regard and later still, in the early 'seventies, came the EMI RLS10 known as the "White Elephant" due to its being painted white and nearly five feet tall - although actually smaller than the cabinets I have at home. I don't remember the drivers fitted - they may have been the Wharfedales again or, possibly, Parmekos. I think this was the last "real" monitor at Abbey Road as after this time producers and engineers preferred headphones; studio speakers were reduced to a secondary role.

Back in 1959 or perhaps it was 1960, Dutton built an enormous horn-loaded speaker which was displayed in, I think, the Daily Express foyer and I remember hearing this thing half way down Fleet Street! I first met Gilbert Dutton at the Russell Hotel HiFi show in 1963 and we enjoyed a desultory correspondence until he retired in 1968. It was shortly after this that I last saw him when he gave a fascinating lecture to the Institution of British Engineers.

And did I tell you about when I built a Karlsonator quarter-wave, taper tubed transmission line using a GEC 8" metal cone with "presence" unit?

Oh well, please yourselves . . . . .

[bob orbell]

No Baggo you didn't tell us, all very interesting reading as always, but don't forget the year is now 2021 and technology has moved forward at an amazing pace, while we still love old style amplifiers powered by thermionic tubes, speakers, in my opinion have been one of the hi-fi products that have reduced in size and still hold their heads high, just my thoughts. And I still love riding my Triumphs and Panther, but the Honda is in another world. Bob

[Baggy Trousers]

Originally Posted by bob orbell

No Baggo you didn't tell us, all very interesting reading as always, but don't forget the year is now 2021 and technology has moved forward at an amazing pace, while we still love old style amplifiers powered by thermionic tubes, speakers, in my opinion have been one of the hi-fi products that have reduced in size and still hold their heads high, just my thoughts. And I still love riding my Triumphs and Panther, but the Honda is in another world. Bob

Well Bob, I accept everything you suggest and without reservation - almost. I think your reference to the Honda summarises my position very well indeed.

I readily admit that I'm a dinosaur, partly because I find refuge in dinosaurism preferable to living in the present world, but that's an old fogey's viewpoint and it's just as well that it's not shared by everyone. I agree that miniaturisation and technological advance has, for the most part, provided many benefits and improvements since I first enjoyed myself with kinkless tetrodes a long time ago. (My case comes up next week). But in self defence, I might mention that WD and other pretenders to stratospheric fidelity continue with that superlative Mullard circuit so little changed from the Williamsons I built back in the 'fifties.

I also acknowledge the remarkable transition made from steamer trunks to bookcases, but I really think that transducers have fared less well in the intervening years. The orchestral string bass and the bass guitar are both tuned in fourths and share the same pitches - that is about all they have in common. They cannot properly double for each other in their respective fields - I'm reminded that there are those who can distinguish a valve amp from a transistorised one and I believe this must be so. Why else would one continue in pursuit of perfection with an obsolete thermionic technology? This dichotomy is extended to speakers where the American performance car adage that you "can't have too many cubes" prevails at the very top end and where audio quality is not to be compromised. I think this, in itself, rather supports the probity of my argument. Not sure if Dave the Bass still visits the forum but I would be interested to have his comments.

You cannot take a 'cello, slacken the string tension and expect it to sound the same as a double bass an octave lower. The physics don't work that way and I contend that the same applies to speaker design/construction. A parallel can be found in organ pipes. The combination of a 16' foot pipe with one at 10,2/3ds will provide a resultant pitch of 32'. This is a cheaper arrangement requiring less space. Yet it does not have the same character or quality as a proper 32' rank and is easily detected as being a "cheapo" substitute. A bit like the old Goodmans "Acoustic Resistance Unit". Well, sort of. Gracious, you have to be old to remember that!

Despite all the foregoing, I readily accept that I'm probably steaming a little astern of the fleet. For more than 65 years I have ridden Britbikes thinking that they have represented the best of their time - and in many earlier cases, they did - but Bob's reference to the Honda is spot-on. My little XBR has been a wondrous eye-opener. In terms of engine performance, comfort, reliability and general handling, it is the best bike I have owned, with the possible exception of the Manx Norton, but the Honda does not spew oil all over my trousers! I have come to treasure this chuckable, beautifully balanced and very compact machine which is proving an absolute delight. So would I like to have my old bikes back? Emphatically not, because I'm too old and they're too heavy! But, just to keep a foot in the old camp, I still treasure my 1949 Nimbus. But should I embrace small speakers with a more open mind? I have yet to be persuaded.

From long experience, I have come to understand that having an open mind is just an invitation for someone to fill it with rubbish. Or even a bookshelf speaker . . .