Accuton Tweeters - Mid/bass match?

[toxinlab]

Hi there,

I am considering an MTM project and I really want to try the Accuton C23-6 tweeter. Actually, the project I am contemplating is really a 2-cabinet design that puts an MTM on top of a separate woofer cabinet, bi-amped and actively XO'd.

The basis for this is GR Research's PHL/Revelator design:
http://www.webgeekdesign.com/guide/index.shtml


My question is this: Other than Accuton's own mid/bass drivers such as the C79, 88, and 89, which I assume are an excellent match for the C23, does anyone have any experience or recommendations in pairing the C23 with other mid/bass drivers?

Others that I have considered include the Focal Audiom 6WM (or other W-cone mid/basses), ScanSpeak 8530 series, Seas Excel W18E-001 or W15CY 001, or the PHL 1230 that is already part of this design.

I see two options:
1. Determine if the Accuton tweeter will pair nicely with the PHL 1230 midbasses. If so, then simply redesign the crossover to accomodate the different driver. I lean towards this option for many reasons, but I just havent heard enough about the PHL drivers to be totally sold out to this idea. (Anyone care to comment on PHL mid/bass drivers to help me out?)

2. Determine an alternate mid/bass match for the Accuton and then design an entirely new XO for this MTM, and then vary the cabinet dimensions based on the needs of that alternate mid/bass driver.

Two obvious questions arise:
1. Why not just stick with the Revelator tweeter that this kit already has designed for? --Well, I really want that ultimate transparency in the high end, along with the high power handling capacity of the Accuton. Really, I just want to try it.

2. Why not use Accuton mid/bass? --Well, I think its cause I envision the liquidity, smoothness, and warmth that I heard in the Sonus Faber Cremonas (using ScanSpeak slit-paper mids and woofers). I am afraid that an all ceramic system would sound too cold and harsh with solid state amps.

I know this is a lot, but please comment at will.
TL

 

[Jan Deckers]

Try using an Eton woofer. For example a 7inch.

7-360/37 HEX or the 7-375/32 HEX (wich is used by Avalon)

What about a TMM config, where the M is the 7-375/32 HEX and the T is the C23.
I am using the C-12 and C79 ad find them full of details.

Regards,

Jan

 

[CeramicMan]

My question is this: Other than Accuton's own mid/bass drivers such as the C79, 88, and 89, which I assume are an excellent match for the C23, does anyone have any experience or recommendations in pairing the C23 with other mid/bass drivers?

I've got a 2 way system using the C23 and C94. I could have spent a few extra dollars and bought the C95 instead but the C94's 5kHz peak is more damped (judging from the step response plots), it has a lower Qes, and - from memory - a more compliant suspension.

I'd also look at the Excel magnesium cone speakers, or Visaton aluminium speakers such as the "AL 170". A smaller, 130mm speaker might be better if the woofers will be crossed high enough.

In my system I've found that the midrange is really pure and musically sweet. You don't notice the bad sound of paper cone speakers until you hear the alternative, and low efficiency is just a price I'll be more than willing to pay next time. It's more important to get the midrange right than the tweeter IMO, and it's important to get the crossover right. A passive crossover between the mids and tweets is probably going to be a big handicap too, and it will compromise the performance of the amplifier.

...I am afraid that an all ceramic system would sound too cold and harsh with solid state amps...

Definitely not, passive crossovers and class-AB amplifiers being subjected to fullrange audio are what creates the harshness. When the C23 tweeters in my system get intermittent spikes of 10W~15W (after 3rd order HP, 2.7kHz), it means that the music is being played bloody loud. A low power level like that is just begging for a class-A amplifier for the tweeters.

I think that good box design is very difficult with a ceramic midwoofer. Speakers with soft cones are flexible at midrange frequencies which allows the back-wave to quickly escape and mix with the sound you're supposed to hear. Because the cone is so lossy, the sounds inside the box don't have time to become resonant and the result is a mild boxy quality that's not too bad. The C94 (with its stiff cone and very high electrical stiffness: Qes=0.21) makes the box much less lossy, and keeps the back-wave inside the box for a much longer time. Unfortunately, this also means that the sound that does escape is much more resonant. Even though the "box" sound is at a much reduced level, its quality is insanely boxy, it's: boxiness^boxiness. Stuffing material such as polyester wool only does a fraction of the absorption that's needed. It can be a bit fatiguing, and gives the speakers a contradictory nature. It also gives the word "analytical" a bad name.

It'll be a similar story with aluminium and magnesium midwoofers too. To avoid this problem, make the box dramatically oversized (to reduce the SPL inside the box), make a clever infinite baffle design, and/or use a port that's short and wide (so it's lossy at high frequencies.)

 

[scotts]

I am using a C2-11 with a SS 13M/8636 Kevlar and a SS 21W/8554. This combination has worked well though perhaps a little different than what is being proposed and I have used it with tube electronics (Berning ZH 270 and CAT preamp). I am also curious about any experiences with the Accuton tweeter/mid combo. I love what the Accuton does and would like to extend these qualities into the midrange. I have also been impressed with the Avalon and Kharma speakers and consequently, I have acquired a C2-12, C2-88 and Lambda SBP10 for a new speaker design. I was going to utiilize a series crossover. I would appreciate any further experiences on cabinet and x over design.