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Greets!
WRT Altec's MI drivers Vs their cinema/HI-FI drivers, a steeper XO slope and/or applying a removable damping compound such as rubber cement to the metal DC will offset most/all of the frequency response differences at very moderate SPLs, but it's their distortion generating rapidly rising response suspensions/reduced Xmax that causes them to be unsuitable for HI-FI IMO unless you BW limit them to within their Xmax in a compression horn or EQ'd sealed or listen to them at very moderate SPLs.
GM
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Gm,
I think I follow you, I laid out a 416 and a 418, and though I'd don't see any major differences in either the cone compliance, or the spider, (I think) the 418 feels tighter when flexed. Is there more difference than I'm seeing, or is it just that the MIs are more "doped up" (a description also commonly applied to those of us that use 'em)?
If (theoretically) suspensions were equivalent, would the MIs coil handle the extra 0.12" or so added Xmax without coming out of the gap? If the MIs are driven by a tube amp with reduced damping would their performance be a closer match to the others driven SS?
Sorry to be a pain, but these are issues I've long puzzled over.
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GM,
Is the (minimally documented, but generally assumed) peaky, non-linear, response of the MI units the distortion you're referring to, or is there something else? Could you elaborate a little on the differences between the 418/421 variants, vs the 416/515s, or more simply put, MI vs HIFI, and possibly the associated design strategy?
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Clarification of above post to all;
My reference to being "doped up" in my previous post was intended to be a joke. As a musician, (who's never blown a speaker in his life), I'm simply sick of being classified as a gear-abusing, doped-up hippy, by a limited number so so-called audiophiles that claim to love music, yet are only involved as a means of impressing their peers with their collection of over-priced "high-end" gear. Fortuneately, that's an issue that seldom arises on this board, whose members I have a great deal of respect for, and I apologize to any that may have been offended, especially to Tranquil, whose post I hijacked for my rant.
Sincerely
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No offence taken Bfish. I'm also enjoying the conversation between you and GM.
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Greets!
>Is there more difference than I'm seeing, or is it just that the MIs are more "doped up" (a description also commonly applied to those of us that use 'em)?
>If (theoretically) suspensions were equivalent, would the MIs coil handle the extra 0.12" or so added Xmax without coming out of the gap?
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I don't know any of the driver's assembly details, so can only speculate. In today's manufacturing environment they would limit components as much as practical, relying on doping, etc., to make a different model, but these designs go back decades to a time when Altec had the majority market share and could afford to indulge in making many different designs with few interchangeable components, so I wouldn't be surprised if they had different motor details due to more robust VCs to go along with different spiders, DCs, etc..
A re-coner can tell you all the differences, but due to the suspension's rising rate, a MI driver is less likely to come out of the gap since it's designed to keep it from happening, and why the rapidly increasing distortion with excursion.
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>If the MIs are driven by a tube amp with reduced damping would their performance be a closer match to the others driven SS?
Sorry to be a pain, but these are issues I've long puzzled over.
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Somewhat.
I bought some 421-8Hs when they first came out in '72? because I was assured by the local Altec distributor that the only difference between them and the 416-8C was a higher power handling VC, paint job, labels. WRONG!
I wound up making quite a few frat house/pool party speakers with them, but HI-FI they ain't, so no need to apologize, these are valid issues that folks need to understand lest they make the same mistake as I.
GM
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GM,
Thanks! I never did the frat thing, but did get to attend a few pool parties. Strange, isn't it, how or perception of BW and Xmax varies, depending on TOD and BAC?
I've written a new post to carry this on a little further. Thanks to Tranquil for the use of his!
"Till The Wheels Fall Off and Burn!"
BFISH
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Is MDF/Particle board the material of choice for speaker cabinets.Could someone enlighten me on the advantages and disadvantages of using MDF instead of Birch or similar grade Ply.If this has already been discussed in detail please refer me to the thread? I searched and could not find a actual comparison or a reason for using one instead of the other.
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MDF/particle board is a homogenous mixture of glue and sawdust formed into a 4x8 sheet. Plywood, birch or otherwise, is layers of real wood (with real voids) glued together. Not as dense or consistent. MDF is less likely to have internal resonances.
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Take a solid piece of wood. Put one end to your ear and lightly tap the other end. How much sound do you hear. Take a comperable size piece of plywood and do the same thing. The sound should be much less.....Now take a comperable size piece of MDF or particleboard and do it again. The sound should be much less again.
The theory is to NOT ADD any sound that you can't control. Sounding comming from the wood itself as it vibrates because of the sound waves of the drivers can't be controlled. So the best thing is to eliminate/reduce the cabinet from vibrating by using MDF or particleboard.
Professional applications want to acheive this goal also....BUT they also have a goal of being very durable (especially if used in a road band). You don't want to move speakers made from MDF around alot. Plywood is more suited for this.
