Sony speaker project

[Daniel Quinn]

a little more dissent :D

conventional wisdom as it that the rear out put of speakers is to be killed as it smears and causes phase issues and standing waves which are detrimental. hence the reason for padding and absorbent materials . townsend glastonbury use concrete and carpert

steel plate whilst strengthening structure would offer no solution to these issues . I am wrong ? is conventional theory wrong ?

[Dr Bunsen Honeydew]

Yes in both cases you are wrong.

It is provable by ear, and if you read the threads from some members here who have done it have proved it for me. Apart from me having proved it to myself over 20 years ago.

[Dr Bunsen Honeydew]

Well I suppose I will be a little more informative. What you are doing wont kill it, it will alter it, and the alterations make a problem far worse *musically* than the original problem. These things about cabinet reflections were expounded when drive units were paper and thinnish. Now with polymer or polymer/paper drivers especially if doped will only allow LF back and that LF is damped by a sealed cabinet as it only manifests as a pressure wave - now it is simple believe who you want, members asked me in "ask the designer" so I am the designer they asked, so this is my opinion, take it or leave it.

[Daniel Quinn]

If i recall correctly , I may have been the first person on the forum to follow your x-over suggestions so I am more than happy to follow , its just i like my thoughts tlo be coherent even if they wrong

[Dr Bunsen Honeydew]

My principle - filters are the work of the devil as far as music is concerned, only use them when it is unavoidable, be those filters electrical or mechanical. So in the cabinet nothing fibre or soft or rubbery and absorbent, because they don't work, they are mechanical filters, so depending on material shape and size they are only *fully* effective at one frequency, they progressively become less effective at lower frequency, and if you use more and more to get the frequency even lower then more and more they become a storage medium for letting information back via the cabinet but out of phase and musically destructive.

Rigidity solves this problem, increase mass (steel plate) to the point that no information is let back into the system, it is dissipated as heat from vibration, the *only* thing that reflects is high frequency from the plate and that cannot get back past the driver cone as you have already doped that to stop it reproducing any high frequency. AND as I said in the last post by keeping the cabinet air tight then the signal inside the cab becomes entirely an air pressure wave and at low frequencies creates a spring for the driver to work off, to the point that that air pressure takes over from the driver spider and surround to support the driver cone and hold it in position. So again the information in the cab does not get out.

This is so obvious to anyone who has the intelligence to work it out I am mystified by all the guys in white coats who can't see it - brainless twats with letters after their names in my book.

[jammy395]

It is indeed surprising that with the wealth of major speaker manufacturers out there (With huge R&D budget's) that they all seem to churn out the usual
Run of the Mill products, Usualy very expensive and equaly uninspiring.....Which makes it all the more remarkable that some of the industrys best sounds
come from the little guys As Doc touches upon just why is it so difficult for most manufacturers speakers to put a smile on our face and set Toe's a tappin.

I smell a fukin rat - truth is they probably could do musical (stands to reason) For some reason they dont want too.......

[Andrew]

Not sure of its still out there, but there was an account of a speaker designer's travails at Linn on the net. It was a real eye opener. I'm paraphrasing his account here, but every time he got a half decent sound, Ivor would want him to use a cheaper driver or other component. In the end, the poor guy was shackled. I think it was the Helix and Nexus models.

Then there was the account from a techie working for MF......all I can say is oh dear!

No wonder companies fail to create better sound. It's not even a priority it seems. Not when you can make better profits.

[Dr Bunsen Honeydew]

The problems are largely inertia, both from what they learnt when getting the letters after their names and the shoulders of those they are standing on. Plus remember these are employees and keeping a job, especially when a techy, involves bullshitting the people who pay you into them believing you know what you are doing, and a major part of that is inventing a language so the bosses don't understand you.

Plus it has been ingrained that perceived value is more important than real value, so instead of real tech we have bullshit tech, instead of real quality materials we have cheap materials tarted up to look something special. WAF then enters the equation, and remember it is the marketing men who dictate what the techy designs.

It is just another facet of what has become our bullshit industry. People knew more about how to make speakers in the 50's and 60's than they do now. BUT the quality of material used then with the current rip-off mark-ups means real speakers would costs tens of thousands instead of thousands.

Its our fault, we allowed them to get away with it, some people got very fat, and an industry was ruined.

[floydfan]

Have lined the speakers with plate and am waiting for the new binding posts. It was a bit of a shock to find you can spend £50 for a single set ie £200 to bi amp. I bought the £12 set. The plate is not 4mm as I got a deal for 6mm and the guy cut them to size for a tenner. I suppose if I have understood the idea of mass damping this should make no difference and may even be better. As I am feeding the bass driver straight from the amp will the driver try to deliver some of the mid range and should I dope the bass driver, as been discussed earlier, to increase the mass of the cone to attenuate the mid range or would it be better to have a listen first.
I am sure a doping material was mentioned somewhere but I didn't recognise it. Are there any easy well known substances I could use?
Cheers

[Dr Bunsen Honeydew]

Listen first, you may be lucky. If it makes you wince and sounds hard or sibilant then you have a problem. There are gross things you can do and minor things. The official doping materials are hard to get but you can improvise. You need a material that damps the cone but doesn't completely dry out and become brittle. Some rubber based glues that are easily available perform this function. A good one is Bison available from Rapid Electronics http://www.rapidonline.com/mechanical-f ... ml-87-0432 quite often you only need to apply it to near the centre of the cone, spread it with your finger, obviously put the speaker on its back before you do it. After two hours you will be able to listen, if still not right then spread a layer over the cone area, listen again. When you are happy spray over the whole cone with Performix Plasti Dip aerosol. If you have a minor problem then the Performix may be all you need.

Experiment, use your ears and trust them, have fun.