Home audio drivers vs. car audio drivers

Most mobile speakers target specific size and envirmental issues as in size,depth,flush fit,nominal 4ohm impeadence.
when you go to seperates the tweeters are ussually permanently grilled,neodymium magnets,and ferrofluid are most common.And to top it off most all designs expect use in free-air application.Also many off the better car tweeters tend to be focus dispersion so as not to splash highs off many unfriendly vehicle interiors as well as an increase in on axis sensitivity.Material choice is a comprimise for in car sunlight and moistures relentless
assualts.Pl++++++us!Most of the time thiele/small parameters from mobile manufacturers if available,can't be trusted.So what size cabinet vented/reflex or sealed acoustic suspension would you set out to build.
I have heard few rigs made for home from mobile sound gear
which yeilded loud and clean,yet always missed 3 dimensional
accurate sonic picture.IMHO

Gunbei: Most car stereo woofers have a high Qms, which results in a big impedance peak at resonance. This is what causes the bloated, indistinct bass that you hear from the "boom / tizz" vehicles. Lower impedances aren't a problem for a good amp, but as you mentioned, damping factor is reduced.

As a side note, damping factor is NOT the ability of the amplifier to control or load into the driver so much as it is the ratio of how much potential there is for the reflected EMF from the driver to modulate / distort the output of the amplifier. This is a very commonly misunderstood spec with even EE's, designers and manufacturers not knowing how to interpret it or what it really means.

The higher the damping factor, the less susceptable the amp is to being affected by the reactance of the speaker. The ability of the amp to efficiently transfer power into the driver / speaker system ( including cabling ) is what will determine how much "control" the amp has. Unfortunately, there is no spec for this that i'm aware of.

Take a look at this link pertaining to impedances, reactance, loading characteristics and power transfer in the AA Speaker Asylum archives. Pay special attention to the exchanges between myself and that of Dan Wiggins of Adire Audio and to a lesser extent the few responses between myself and Bobby Palkovic of Merlin. One of these two guys is a LOT smarter / more experienced than the other, but i'll leave that up to you to figure out which one it is after reading the exchanges there. While punching in T/S parameters into a computer program and then interpreting the data can provide a lot of useful information, it does not make one a knowledgable speaker designer. Sean
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Thanks for the info Sean! Have a good one.

Sean, I can't figure it out. You say Dan Wiggins can't use a vented box that can outperform a sealed box but he shows how he can. Bobby is lowering bass below tuned freq. which you say increases distortion and he says he found a way around that.
Sounds like you don't think either one knows what they are doing / following the laws out physics.
To my ears Dunlavy's sounded much less dynamic than Virgo III's or B&W. And B&W publishes distortion under 1% with their vented boxes. Bass is very tight and picks up on the beat (toe tapping).

Cdc: "You say Dan Wiggins can't use a vented box that can outperform a sealed box but he shows how he can."

Beat it in what manner? Given optimally tuned designs, a vented box may have greater extension and output, but it will never have the same amount of definition and transient response that a sealed box can achieve. Like i said, quantity vs quality.

"Bobby is lowering bass below tuned freq. which you say increases distortion and he says he found a way around that."

That is what Bobby says. As i mentioned in that thread, NOWHERE in the Stereophile review is distortion measured or quoted.

"Sounds like you don't think either one knows what they are doing / following the laws out physics."

I think that Bobby has a much better idea of what he's doing than Dan. Dan is all about computer designing a product for maximum quantity, not maximum quality. If you doubt this, look at the Adire website and you'll see the "monster" sized woofer with mega-excursion that they are working on. Given that Dan doesn't understand the difference between an amp being able to load into a speaker and what damping factor means, it is pretty obvious that he's letting the computer do his thinking and work for him.

On the other hand, Bobby is about hands-on experience and tweaking for optimized results with minimal trade-offs. He understands what the words "control", "loading" and "damping" mean.

Dan will get you a lot of sound. Bobby will get you good sound.

"To my ears Dunlavy's sounded much less dynamic than Virgo III's or B&W. And B&W publishes distortion under 1% with their vented boxes. Bass is very tight and picks up on the beat (toe tapping)."

Dunlavy's had their own problems, just like any other mass-produced speaker. On top of that, most people aren't used to listening to "tight" bass with minimal ringing. Facts is facts, personal preferences are something all-together different.

Try taking a look at this >website. Click on "tech notes" and then "bass loading" and read that. He basically repeats the same things that i said in that and a few other threads. For sake of clarity, i'm not taking credit or saying anything that hasn't been said and proven to be fact long ago.

If you doubt these facts or just want to delve deeper into the subject and learn for yourself, pick up a copy of Vance Dickason's Loudspeaker design cookbook. As i've mentioned before, I would always encourage one to learn for themselves, both through reading and hands on experience. The more that you know, the less bullshit you'll be forced to unknowingly swallow.

Believe me, i learned the hard way. I used to think that sealed speakers were for idiots when i was younger. Why would anyone want a speaker that didn't play as loud, go as low or took more power to operate? The answer is obvious once you learn how and what to listen for. Like i said before, quality vs quantity. Sean
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