Searching for an excellent midrange...

[youyoung21147]

Hello,

I'm currently building a big 3-way active system with the following drivers :

- 15 inch B&C 15PS100 from 20Hz to 160Hz
- Seas 27TBFC/G dome tweeter from 1900Hz to 20kHz

I initially thought I'd use the Supravox 215RTF64 as the midrange driver from 160Hz to 1900Hz.

http://www.supravox.fr/haut_parleurs/215_RTF.htm


But it seems that no serious distorsion number is available for this driver, which probably means "it shouldn't be shown".

So I was wondering if you guys knew a really good midrange driver that could suit my purpose :

- ultra low distorsion from 150Hz to 2000Hz
- high SPL capability (112dB)
- efficiency >90dB
- excellent transient response
- no energy storage issues
- amazing resolution
- objective and complete measurements available
- price < 200$

Thanks in advance !

[Cal Weldon]

Have you looked at the Davis? It's close to budget.

http://www.parts-express.com/pe/psho...Number=297-572

[youyoung21147]

Nice looking speaker, a French one, but it is really expensive lol. And I still have no measurement concerning distorsion...

Mr Linkwitz seems happy with the Seas W18EX001, but he says that it becomes "less good" above 1200Hz...

http://www.linkwitzlab.com/x-mid_dist.htm


Has any of you used this driver ? Is it this one used in the Orion speakers ?

[joe carrow]

Since you are in France, it seems like an obvious choice would be PHL-

http://www.phlaudio.com/

They do pro audio drivers, and I believe that they are fairly highly regarded.

Paper drivers may not be as pistonic as magnesium cones, but they tend to have more manageable breakup, and are often usable to a higher frequency. Pro audio drivers are, by necessity, low distortion with high efficiency.

Your tweeter has often been used as low as 1500 hz with a 4th order crossover- the only thing pushing your crossover higher is the high SPL you require.

I hope that helps!

[youyoung21147]

Originally posted by joe carrow

Paper drivers may not be as pistonic as magnesium cones, but they tend to have more manageable breakup, and are often usable to a higher frequency

I hope that helps! [/B]

Thanks for the PHL idea ! I know a sound engineer who told me PHL drivers where excellent drivers.


Could you be more precise when you say paper is "less pistonic" ? Does it means paper distorts more the original signal, but stops playing more progressively ?

I'm not really wanting to cross the tweeter lower than 1890Hz because then it would need higher Xmax at full SPL.

[youyoung21147]

I'm really shared between three drivers :


- The Seas W18EX01 : near perfect CSD which leads me to believe it has the best low-midrange articulation of any midrange driver. Unfortunately, it has unacceptable HD levels above 1kHz which may put it apart from my system...

- The Vifa XG18 : on the paper it has the lowest distorsion, but its CSD is somewhat less clean in the low-midrange... And it has a really poor efficiency which may not be suitable for the high-SPL I need.

- The PHL 1230 : it has good efficiency, correct linearity, and is advertised as "the ultimate midrange driver". Little problem : no distorsion measurement is available anywhere on the Internet, which leads me to believe it's one of those "audiophile" drivers which has a funky distorsion/frequency response profile that hides design flaws...


Could you help me see clearer through that mess ? Any other ultimate midrange driver idea ?

[kepa1]

Salut,

It seems like real midranges don't go as low as you want to cross the 15". If possible, 300hz might be more reasonable, and give you more choice in the pro sound market (see PHL 17cm Midranges.) I was thinking of the Audax PR170 but it can't be used below 500hz.

[holdent]

How about the Seas MCA15RCY (http://www.madisound.com/cgi-bin/ind...13048&pid=1596)? I've read good things about it but never used it myself - see for example http://www.markk.claub.net/Testing/M..._test_data.htm or http://www.troelsgravesen.dk/PMS.htm

[youyoung21147]

kepa1 : the low crossover frequency is not definitive, it was just a starting point. I think I may push the 15PS100 up to 200-250Hz. Moreover, all drivers are crossed 24dB/oct.

holdent : Your test page is really really interesting !! I'm reading all the tests on this website currently, this link you gave me is a true gold mine


Maybe I'll find my ultimate driver there lol

[joe carrow]

Originally posted by youyoung21147



Thanks for the PHL idea ! I know a sound engineer who told me PHL drivers where excellent drivers.


Could you be more precise when you say paper is "less pistonic" ? Does it means paper distorts more the original signal, but stops playing more progressively ?

I'm not really wanting to cross the tweeter lower than 1890Hz because then it would need higher Xmax at full SPL.

I mean that if you were to examine the exact shape of the paper and metal cone drivers, below a critical frequency the metal cone will deform hardly at all until it reaches that critical frequency, then it will start to ring and perform poorly.

The paper will start to flex progressively as frequency increases, and although it will not cause the extreme distress of the metal cone breakup, the behavior will be exhibited over a much wider range and will not leave a major portion of the driver's usable bandwidth completely unaffected.

As with all design and engineering, it is an exercise in trading good and bad characteristics to get the best configuration available.

I think you've seen this accurately in your examination of the Seas Excel driver. It's truly a fantastic driver, below a critical frequency. Above that, great care must be exercised to get any more usable extension.

If you're looking at "ultimate drivers", you really need to invest in some test equipment and learn to measure distortion on your own. Zaphaudio.com and Mark K's testing site liked by Holdent are both good starting points for learning more about how to do this.

If you can test your own drivers, there's a great chance that you'd be able to test that PHL driver to see if it lives up to the marketing hype. Since you're in France, I assume that shipping will be a manageable expense for that driver. Generally if you don't solder to a driver and don't mark it with screws at all, companies will accept returns.