Best driver for short TL

[MikeFarad]

I am building a short TL (after Cockroft, "Speaker Builder" mag, 1/88 ) and want to use a 4" coaxial (car) driver. I listen mostly to classical music and jazz and must have fast, accurate and smooth mids & highs. I'm a bit concerned because I understand that car speakers have a tendency towards hot, harsh high ends. I'm considering Infinity (Kappa42.5I or Reference4002I,452I), MB Quart(Reference RKC110), etc. - trying to find the best for under $200. I read that generally textile(i.e.-4002I) and silk domes (i.e.-452I) are smoother and more "musical" than metal ones(i.e.-MB Quart RKC 110). The Kappa42.5I has a ceramic composite dome which they say is better than either. Has anyone had any experience with these drivers(especially the Kappa42.5I), or have any other suggestions. Any help will be greatly appreciated. TIA

[sreten]

Hi,

IMO you should be concerned about trying to use car drivers,
for lots of reasons which I could take pages to explain but
the short version is simply don't go there.

I'm not familiar with the TL design you mention but I'd suggest
you start here for the drivers and crossover. If you compare what
this involves compared to a car two-way, with a single capacitor
for the tweeter, hopefully you''ll understand why car speakers
are not a good idea.

http://www.speakerbuilder.net/web_fi...ts/DBP/dbp.htm

half your budget and probably at least twice as
good as any $200 car speakers you could use.

If you want something more expensive then try starting here :

http://home.hetnet.nl/~geenius/HATT-III.html

sreten.

[Timn8ter]

I'm quite pleased with the results of my bipole ML-TQWT. I built it with tweaked RS 40-1197s. The Fostex FE-103 could be used without tweaking and probably sound great.

http://www.alegriaaudio.com/bipole_voigt_pipe.htm

[sreten]

Originally posted by Timn8ter
I'm quite pleased with the results of my bipole ML-TQWT. I built it with tweaked RS 40-1197s. The Fostex FE-103 could be used without tweaking and probably sound great.

http://www.alegriaaudio.com/bipole_voigt_pipe.htm

Hi Timn8ter,

so that's what you'd call a short TL is it ?

sreten.

[Timn8ter]

It's a relative term

[sreten]

I suspect this is nearer the TL design mentioned ........

sreten.

[Timn8ter]

How do you determine the cross-sectional area of the pipe in a design like that? Is the answer contained in another thread or page somewhere? I've not tried that in the MathCAD worksheet. Oops....didn't mean to hi-jack.

[MikeFarad]

Thank you for your replies. Let me elaborate a little. My enclosure is an 18" length of 5" (4.375" ID) drain tile. The driver is mounted in one end (facing up) and the whole thing is raised about 5" off the floor on a base by 3- .25" sharpened rods. They are supposed to sound best leaning slightly against a wall (a la Cockroft), but they do very well away from walls, too. I don't have the necessary free wall space for comparison. One would never guess that the sonic image they present was from a 4" driver. I am currently using a pair of Ultimate coaxes (mod U4206) that PartsExpress was closing out (list around $35.00). 4" polypropylene cones, 1" polycarbonate domes. And yes, the first thing I did was replace the electrolytic caps with poly-somethings, whatever I had on hand. One of the drivers got damaged, so I thought I'd go for an upgrade. Intrigued by silk domes. I went for a car speaker because I wanted coaxial point source projection. Besides, it seemed a natural for this design. I would like very much to hear, briefly, some of the reasons for sreten's condemnation of car speakers. I'm not that familiar with auto sound per se. That Seas woofer-mid (L12RCYP-H1207) looks very interesting . However, it's Qts of .28 seems too low for a TL.

[GM]

>IMO you should be concerned about trying to use car drivers,
for lots of reasons which I could take pages to explain but
the short version is simply don't go there.
====

As a general rule, I agree, but if the latest version of Infinity's Kappa series is at least as good as the original, then IMO they are an exception to it and a cut above the Dayton units.

Unfortunately, later versions of products tend to be 'improved' only by their profit margins due to cost cutting, so as always, YMMV.

There are a couple of inexpensive whizzer coned Pioneer drivers that have a following on the FR forum, though require some tweaking, but are too big for Mike's app..

====

>I'm not familiar with the TL design you mention but I'd suggest
you start here for the drivers and crossover. If you compare what
this involves compared to a car two-way, with a single capacitor
for the tweeter, hopefully you''ll understand why car speakers
are not a good idea.

====

For a short TL, a fairly high Q driver works well, so car audio drivers are a viable, if grossly overpriced, option. WRT the Infinity Kappa series, the originals are wide BW midbass drivers with an inductor and the silk dome tweeter has a 3.3kHz? 2nd order IIRC. Anyway, they measured very flat in-room, with much better imaging/soundstaging than a typical 'HIFI' two way, and surprisingly neutral sounding.

====

>My enclosure is an 18" length of 5" (4.375" ID) drain tile. The driver is mounted in one end (facing up) and the whole thing is raised about 5" off the floor on a base by 3- .25" sharpened rods.

====

Hmm, this equates to a ~175.3Hz Fb unless there's a vent, so not much happening. The Fostex FE103E gets rave reviews, doesn't need a tweeter, is cheap, and as end loaded pipe sims go, is flat with ~97dB sensitivity to 200Hz before rolling off.

Plugging up the bottom end and adding a vent lowers the response to below Fs, though at a lower ~93-95dB sensitivity down to ~100Hz depending on stuffing density before rolling off.

====

>I would like very much to hear, briefly, some of the reasons for sreten's condemnation of car speakers. I'm not that familiar with auto sound per se.

====

Go to a store where they have one of those big setups that allow you to select different speaker pairs and save us lots of typing.

GM

[sreten]

Originally posted by GM



====

For a short TL, a fairly high Q driver works well, so car audio drivers are a viable, if grossly overpriced, option. WRT the Infinity Kappa series, the originals are wide BW midbass drivers with an inductor and the silk dome tweeter has a 3.3kHz? 2nd order IIRC. Anyway, they measured very flat in-room, with much better imaging/soundstaging than a typical 'HIFI' two way, and surprisingly neutral sounding.

====

====

I would like very much to hear, briefly, some of the reasons for sreten's condemnation of car speakers. I'm not that familiar with auto sound per se.

====

Go to a store where they have one of those big setups that allow you to select different speaker pairs and save us lots of typing.

GM

Hi,

I never argue with a man armed with measurements .......

Doing some listening for a friend for in-car coaxials
the Infinity's seemed to be a lot better than most.

Some of the better drivers (usually component pairs)
do have more advanced crossovers.

For the intended application, an 18" pipe, discussions of
baffle step compensation and the like needed for home
speakers and not needed in-car seems pointless.

Both my suggestions are entirely unsuited to an 18" pipe,
you can see what I thought you meant by a short TL.

I hope it didn't appear I was condemning all car speakers,
just that for home use there are concerns that need to
be addressed, but for your intended application most of
these concerns are not really relevant.

Generally using car speakers as home speakers needs
complete crossover redesign, and without measurements
this redesign is impossible, and many car drivers parameters
do not suit typical home size speaker boxes for bass alignment.

sreten.

P.S. Trust your ears, and learn how to compensate for the
usual wall of sound mounting in shops versus in-car placement.
My brother needed some new speakers for his car. He was
surprised when I chose the cheapest 4" coaxial 2-ways in the
shop and even more surprised at the results when he fitted
them into his car doors.........