Absolute best LF Driver for Music Applications

[jxo]

Looking for views on sub design and driver choice for my music only system. I posted similar request on the AVS board. A few years ago Nick McKinney and Mark Seaton gave me some great design advice but I let it slip and never built it. It's time to start again.


1. Goal: integrate single box sub into existing high end, music only system. Musical fidelity is key; no home theater stuff. I realize that multiple subs would be best but I can't do it; one box only and I want to make it good.

System: ARC tube gear (amp and preamp with no bass management); SACD and vinyl.

Room: 35x15x9-1/2

Listening: full range of music. Decent but not insane SPLs. Much orchestral work but really low end organ stuff is once is a blue moon.

2. Mains: custom; focal audiom T5s with PHL 1240s in MTM configuration; ported 24x12x8 cabinets. My guess is they inch down in the 40-50 hz range.

3. Current plans:

Sealed or PRs? at the moment leaning in favor of simple sealed but would toy with the idea of PRs. Nick McK and Mark Seaton favored dual PRs a few years ago. I was looking at a couple of different Lambda drivers PB, SAL and TD15X, if memory serves me.

Max cabinet size: 25x20x20 external.

Xover: am hyper sensitive about signal degradation to the mains but feel that a high quality high pass makes sense to filter the mains for the obvious reasons. Thinking either Bryston or Marchand active xover (cheaper brands spook me). Am not impressed with the cheaper Velodyne, Rane, Reckhorn, Behringer products (but could be convinced otherwise).

Rythmik's site says all the right things about fidelity and the servos look cool but my instinct is they are not right for my setup. Their passive xover plug looks interesting but it has a 100Hz xover point and a very shallow slope. I am thinking instead of a more common 60-80 Hz xover with 12 or 24db slope-- symetric. I assume the lower xover point should increase flexibility with the driver choice (i.e., some of the monster excursion drivers may work for me if I keep them away from the 100hz and above range).

Amps: would use Crown or QSC-- am not picky on this front.

Drivers:

1. TCSounds LMS 5400
2. TCSounds 3000
3. Rythmik 15" servo (but this would entail using the servo plate amp as well; by the looks of it appears to be similar to the TC Sounds 1000 with servo sensing coil installed; althought the servo looks cool, this seems better suited to higher xover points and smaller satellite speakers and I could do better with driver and electronics quality)
4. CSS SDX15 (new; low inductance is one of the selling points; but with a 60-80 hz xover, who cares?)
5. old stock Lambda, eg the TD 15x (assuming they exist)
6. Apollo and TAD drivers were recommended but I know nothing about them
7. Dayton Reference RSS390 HO 15" was recommended (maybe with 2 per box).


4. Budget: none; if the results and quality justify it, then I'll do it...

5. Cabinets: max size= 25x20x20 external; will have someone else make them.


Recommendations and views would be greatly appreciated.

Regards,
Jim

[ThomasW]

That's not exactly a small room.

How far will you sit from the sub and is it on or off axis from the mains?

[jxo]

That's not exactly a small room.

How far will you sit from the sub and is it on or off axis from the mains?

Placement will not be optimal.

I sit approx. 2/3 down one of the long walls with the mains across the room with one main speaker approx 4 ft from the side wall and the other about 7 feet away along the same opposite long wall.

the sub will be placed on my side of the room (away from the mains) near the closest corner, i.e., opposite the first main speaker described above. the sub will be only 3-4 feet away from the seating spot.

[cjd]

You don't need that room next door do you?

[Mazeroth]

You don't need that room next door do you?

:rofl:

[jxo]

You don't need that room next door do you?

should I seal it or port it? I could convert two of the windows into PRs and install 4 18" drivers in each of the two doors. The doors could remained hinged provided the seal is tight when they're closed.

[ThomasW]

Porting an entire room or very large space is folly given the pipe resonances created by the huge port.

[cjd]

should I seal it or port it? I could convert two of the windows into PRs and install 4 18" drivers in each of the two doors. The doors could remained hinged provided the seal is tight when they're closed.

Well, the PR concept isn't going to work very well.

The rest could have you a superb sounding sub, assuming you actually go sealed. Order up some IB specific 18" FiCarAudio drivers.



Attic works too if you have such. Or basement. Or garage...

C

[DS-21]

Sealed or PRs? at the moment leaning in favor of simple sealed but would toy with the idea of PRs. Nick McK and Mark Seaton favored dual PRs a few years ago. I was looking at a couple of different Lambda drivers PB, SAL and TD15X, if memory serves me.

Depends on the driver.

Xover: am hyper sensitive about signal degradation to the mains but feel that a high quality high pass makes sense to filter the mains for the obvious reasons. Thinking either Bryston or Marchand active xover (cheaper brands spook me). Am not impressed with the cheaper Velodyne, Rane, Reckhorn, Behringer products (but could be convinced otherwise).

The Velodyne SMS-1 is a really good piece of gear. Unlike the Bryston or Marchand it offers remote control (key for tweaking at the listening position), more flexible tuning options (phase, parametric EQ, selectable slopes/frequencies) and so on. It also has a built-in measuring rig (you supply the screen) that helps in the placement and tuning process. It can also output balanced line signals, for maximum ease of interface with pro amps. No need to buy a Cleanbox.

Amps: would use Crown or QSC-- am not picky on this front.

I've become a fan of the Crown XTi series, because of the built-in DSP.

4. CSS SDX15 (new; low inductance is one of the selling points; but with a 60-80 hz xover, who cares?)

You do. High inductance means energy storage and frequency response nasties within a subwoofer's passband. Lower inductance is always better for people who care about accurate music reproduction. For reproducing a synthetic explosion -mimicing sound conjured up by a Hollywood sound guru, that's the "who cares" situation?

[jxo]

Depends on the driver.



The Velodyne SMS-1 is a really good piece of gear. Unlike the Bryston or Marchand it offers remote control (key for tweaking at the listening position), more flexible tuning options (phase, parametric EQ, selectable slopes/frequencies) and so on. It also has a built-in measuring rig (you supply the screen) that helps in the placement and tuning process. It can also output balanced line signals, for maximum ease of interface with pro amps. No need to buy a Cleanbox.



I've become a fan of the Crown XTi series, because of the built-in DSP.



You do. High inductance means energy storage and frequency response nasties within a subwoofer's passband. Lower inductance is always better for people who care about accurate music reproduction. For reproducing a synthetic explosion -mimicing sound conjured up by a Hollywood sound guru, that's the "who cares" situation?

DS 21: thanks. The CSS SDX 15 is moving up the list. Can you comment on the quality of the high pass in the Velodyne? If I recall its a fixed 80Hz but don't recall the type or the slopes. Will I hear a difference in my mains if I high pass them through the Velodyne vs. an expensive Bryston xover?

[zkaudio]

seems to me if you are using a built in crossover in your receiver in combination with the crossover on the sub amp, quality really isn't an issue no?

[Dennis H]

For music, you're looking for low distortion rather than max SPL, especially at the higher sub frequencies, because music doesn't have all that much really low stuff. I think Jon and Jeb have tested the Aurasounds to be cleaner than the other drivers mentioned. Do a search here for their comments. The 12" NS12-513-4A Jon is using isn't a real long-stroke driver so you'll need several of them if you want really loud SPL.

http://www.madisound.com/aurasound.html

[ThomasW]

seems to me if you are using a built in crossover in your receiver in combination with the crossover on the sub amp, quality really isn't an issue no?

He's using ARC (Audio Research Corp) separates, not a receiver http://www.audioresearch.com/

[DS-21]

DS 21: thanks. The CSS SDX 15 is moving up the list. Can you comment on the quality of the high pass in the Velodyne? If I recall its a fixed 80Hz but don't recall the type or the slopes. Will I hear a difference in my mains if I high pass them through the Velodyne vs. an expensive Bryston xover?

I couldn't tell. For one thing, I suspect my approach to electronics is more "objectivist" (though I hate that word because of the political connotations) than yours. For another, I don't use that function. I use a receiver that performs a direct PCM -> PWM conversion rather than discrete D/A and amplification sections, and all of the bass management is done in the digital domain because of that. (Vinyl and radio are digitized.) I didn't even know that the the mains highpass section of the SMS-1 was so limited, to be honest, because I've never considered using it.

[jxo]

thanks all.
1. I have old electronics with no existing xover or EQ capability. I have an old AC Richter Scale that I may put into service until I make up my mind. Am likely to go with a Marchand xover with 60 and 80 Hz capability (12 or 24 db slopes) and QSC plx amplification.

2. A number of people have mentioned the Aura Sound drivers and I am beginning to understand from you all they may have advantages over comparably sized drivers/ higher excursion/high SPL drivers from TC Sounds, like the 5400.

If I consider the $1000 single driver approach, am I correct to assume that (1) the 5400 will provide relatively greater depth and SPLs and (2) the Aura Sounds will be cleaner, lower distortion and higher fidelity in the higher frequencies?

Am still keeping an eye on the SDX 15; I know its new, but am curious how people would think it would compare to a 15" Aura Sound in a sealed system.

[oxcartdriver]

Xover: am hyper sensitive about signal degradation to the mains but feel that a high quality high pass makes sense to filter the mains for the obvious reasons. Thinking either Bryston or Marchand active xover (cheaper brands spook me). Am not impressed with the cheaper Velodyne, Rane, Reckhorn, Behringer products (but could be convinced otherwise).

I use a velodyne sms-1 for bass management at times. Using the high pass in the sms-1 does generate some noise. For bass management the SMS-1 works really well, as a high pass filter the options are limited and non-adjustable.

[ThomasW]

First can you do an IB? If so lets focus on that and choose drivers accordingly.

[zkaudio]

Great thread, has anyone had experiences with low and high inductance drivers crossed over at similarly low points? 60-80hz. seems all speculation at this point, I have to say though, in terms of your ruling out of the rythmik, I have to disagree that it shines in the "higher frequencies"... show me a non servo sub that will stay flat as low as the ds15 in a similar box without eq.

[JonMarsh]

.

Great thread, has anyone had experiences with low and high inductance drivers crossed over at similarly low points? 60-80hz. seems all speculation at this point, I have to say though, in terms of your ruling out of the rythmik, I have to disagree that it shines in the "higher frequencies"... show me a non servo sub that will stay flat as low as the ds15 in a similar box without eq.

This is sort of a meaningless proposition, because the servo provides the EQ

OTOH, low VC inductance correlates to lower upper bass harmonic distortion, because of lower inductivity modulation with driver displacement.

Personally, I think long throw drivers work just fine for HT special effects in the area below 40 Hz. But getting the best integration with main speakers for music generally occurs when the so called "sub" is capable of clean response to an octave above the chosen crossover frequency, and the same same for the "mains". For an 80 Hz crossover (don't recomend lower due to obvious localization issues), this is good FR and some PBW for the mains to close to 40 Hz, and clean response for the sub driver up to 150 Hz or so-

The low inductance moderate throw drivers (12-18 mm Xmax) seem to inherently full fill these requirements better.

A good servo (and I've heard the Ryhtmik is a good servo setup), will "force" the driver to conform with the target response; but sometimes a flat curve is not the best target response, due to room positioning, so even a servo sub can benefit from EQ, unless the placement is done carefully on an acoustic basis, as well as picking the listening position similarly.

Just my 0.02 - what ever makes you happy in the long run is all YOU need to really worry about.

[noah katz]

"Porting an entire room or very large space is folly given the pipe resonances created by the huge port."

"the PR concept isn't going to work very well."

Don't understand either of these comments.

A large volume means shorter vent length and less resonance problem.

PR retains advantage of not having this pipe resonance at all, and gives better acoustic isolation of backwave ouput.

[mrogowski]

Great thread, has anyone had experiences with low and high inductance drivers crossed over at similarly low points? 60-80hz. seems all speculation at this point, I have to say though, in terms of your ruling out of the rythmik, I have to disagree that it shines in the "higher frequencies"... show me a non servo sub that will stay flat as low as the ds15 in a similar box without eq.

Yup, it sure is. One industry expert shared his view with me about the reason behind (trying to) lower inductance in subs, and it wasn't positive.

To the OP, if it is clean, low distortion good quality sound you are after, and can afford it, the Auras are at the top of the list.

Best regards,
Mark

[Dennis H]

Mr. Rythmic shared a bit of background on his designs over at AVS and it's pretty clear that they shine most at low frequencies, not high frequencies. Short version, the servo concept doesn't work above the frequency where the driver hits its impedance minimum, typically 100 Hz or so. He's looking for drivers with a higher frequency impedance minimum, that can be modified with a sensing coil, but no joy so far.

Edit: Jon is of course correct that the servo circuit provides the EQ so comparing to another sub with no EQ isn't fair. Apples and tractors.

[jxo]

Yup, it sure is. One industry expert shared his view with me about the reason behind (trying to) lower inductance in subs, and it wasn't positive.

To the OP, if it is clean, low distortion good quality sound you are after, and can afford it, the Auras are at the top of the list.

Best regards,
Mark

Auras are indeed at the top of list with the new SDX 15 very close. Awaiting feedback on the SDX 15.

[tf1216]

What about ATC subwoofers? I have one that I would love to use but not the time nor room for it.

If you want some great ideas ScottG on diyaudio.com has a vast amount of knowledge to lend.

[ThomasW]

If you want some great ideas ScottG on diyaudio.com has a vast amount of knowledge to lend.

Scott G. is also a member of this forum and posts here when he has something to contribute.

[looneybomber]

Auras are indeed at the top of list with the new SDX 15 very close. Awaiting feedback on the SDX 15.

Keep an eye on this thread. I think Bob will be coming out with some tests pretty soon.

http://www.avsforum.com/avs-vb/showthread.php?t=864243

[ThomasW]

I don't often do this but since it's on topic.....

This is a snip from a Bass-list post made by Deon Bearden when asked about the "best" subwoofer...he starts out talking about independent Klippel testing of the 18" Aura woofer and compares it to the TC-Sounds LMS-5400

For those that don't know Deon worked for a short time at TC-Sounds. In his original "the Beast" subwoofer, Deon used the AuraSound drivers. The person asking this question (Chris A.) has a pair of HUGE EBS designs created by Deon, each box constains 2 Aura 18"s. The question was raised because Chris is building a dedicated HT and will be using a dozen 18" drivers.

However - those area's are mostly marketing hogwash. They exhibit significantly more distortion at a given output than the 5400's you referenced. Having Klippeled the Aura NRT (new and old) they are nothing really special. Their claim of 75mm p-p is with 100% of the coil through the gap. (1" coil, 2" gap). BL^2/Re of 93 is nothing spectacular.

Having retooled the cones for the 5400 series from TCS (they had been Alu and had a cosmetic crimp around the periphery that was failing with all the motors that had high Bl - (poor QC and design) the new cone is Ti and super strong (I can stand on them without caving them in - I'm not heavy at only 180 - but - they are waaay stronger than they used to be) new 5400's are formidable. In fact at their price they have no peer. Absolutely none.

They out displace by a significant factor those Aura's. With a BL^2/Re of 180 electromotive and a TRUE linear 38mm 1 way linear motor travel, the 5400 moves a lot of air cleanly. The only distinct issue with the 5400's is significant hoop stress towards the limits of travel, which is audible at 2.5" and above excursion. In system you can't detect it on music, speaking raw test tones. I tried to get the surrounds re-tooled but... well I can't divulge the issues.

Anyway, almost every large displacement driver I've seen has similar issues.

[jxo]

I don't often do this but since it's on topic.....

This is a snip from a Bass-list post made by Deon Bearden when asked about the "best" subwoofer...he starts out talking about independent Klippel testing of the 18" Aura woofer and compares it to the TC-Sounds LMS-5400

For those that don't know Deon worked for a short time at TC-Sounds. In his original "the Beast" subwoofer, Deon used the AuraSound drivers. The person asking this question (Chris A.) has a pair of HUGE EBS designs created by Deon, each box constains 2 Aura 18"s. The question was raised because Chris is building a dedicated HT and will be using a dozen 18" drivers.

thanks a lot Thomas; right when I thought I was making some progress, you have to introduce facts and objectivity into the debate.