Dual sealed subs using RL-s12's?

[KEW]

Hey,
I am looking for the most articulate sub I can get in a fairly compact form factor.
I had mostly decided to get a pair of Rythmik F12G subs (GR Research drivers), but them Warpdrv pointed out the Dayton pre-built subwoofer cabinets:
http://forums.audioholics.com/forums/showthread.php?t=60730

I'm wondering if I would do better to go with something like the RL-s12.

So, my first (and somewhat redundant) round of concerns/information/questions:
1) Would this be the best driver to use for articulation? This is for 100% music and I don't care about subsonic slam. I just want to get as much detail as possible out of a sub.

2) I listen at a maximum 95dB peak SPL (C weighted, fast response), so SPL isn't really much of an issue. I mention this because I've had speakers in the past (Lahti's) that didn't achieve a good sound until the volume went up. I want subs that sound full at 65dB!

3) I keep reading how a larger sub can be as quick as a smaller one because it can create the same SPL with a shorter stroke; however, it still seems like a matter of physics that the lighter cone will be a little quicker on the initial attack even though the larger driver can quickly overtake it wrt the amount of air moved. What is the best 10" driver made (budget $600 each)? I guess I am both ignorant and stubborn, but is their a good link to a thorough treatment of this issue involving actual empirical results or at least theoretical calculations? I simply need to educate/convince myself.

4) I want to limit the size to the 2 cu. ft. box. On the SoundSplinter site, 2 cu.ft. is recommended as the optimum size for their RL-p12 driver.
4.5 cu.ft. is recommended as optimum for the RL-s12 and 2cu.ft. is the very bottom of the "acceptable" size for the s12. Would this mean that the p12 might out perform the s12 if confined to the 2cu.ft. box?

5) From what I've read, it seems like SPL and extension drive most DIY designs/builds. I am on the other end of the spectrum and suspect any reasonably competent attempt would exceed my requirements on those two counts, but I'm not sure the best drivers for SPL and extension are the best for articulation. IOW, I don't know if that makes for a radically different set of parameters for the drivers. Is there a spec. which correlates to the transient capability of a driver?

I'm sure these are ignorant questions, but I've got to start somewhere!

Thanks for the help!

 

[TLS Guy]

Hey,
I am looking for the most articulate sub I can get in a fairly compact form factor.
I had mostly decided to get a pair of Rythmik F12G subs (GR Research drivers), but them Warpdrv pointed out the Dayton pre-built subwoofer cabinets:
http://forums.audioholics.com/forums/showthread.php?t=60730

I'm wondering if I would do better to go with something like the RL-s12.

So, my first (and somewhat redundant) round of concerns/information/questions:
1) Would this be the best driver to use for articulation? This is for 100% music and I don't care about subsonic slam. I just want to get as much detail as possible out of a sub.

2) I listen at a maximum 95dB peak SPL (C weighted, fast response), so SPL isn't really much of an issue. I mention this because I've had speakers in the past (Lahti's) that didn't achieve a good sound until the volume went up. I want subs that sound full at 65dB!

3) I keep reading how a larger sub can be as quick as a smaller one because it can create the same SPL with a shorter stroke; however, it still seems like a matter of physics that the lighter cone will be a little quicker on the initial attack even though the larger driver can quickly overtake it wrt the amount of air moved. What is the best 10" driver made (budget $600 each)? I guess I am both ignorant and stubborn, but is their a good link to a thorough treatment of this issue involving actual empirical results or at least theoretical calculations? I simply need to educate/convince myself.

4) I want to limit the size to the 2 cu. ft. box. On the SoundSplinter site, 2 cu.ft. is recommended as the optimum size for their RL-p12 driver.
4.5 cu.ft. is recommended as optimum for the RL-s12 and 2cu.ft. is the very bottom of the "acceptable" size for the s12. Would this mean that the p12 might out perform the s12 if confined to the 2cu.ft. box?

5) From what I've read, it seems like SPL and extension drive most DIY designs/builds. I am on the other end of the spectrum and suspect any reasonably competent attempt would exceed my requirements on those two counts, but I'm not sure the best drivers for SPL and extension are the best for articulation. IOW, I don't know if that makes for a radically different set of parameters for the drivers. Is there a spec. which correlates to the transient capability of a driver?

I'm sure these are ignorant questions, but I've got to start somewhere!

Thanks for the help!

I think you have some misconceptions. The characteristics you are looking for come down to Qtc. I think you are looking for a sealed sub with a Qtc somewhere in the neighborhood of 0.5.

Neither of those two drivers are very promising for home HT. I have had a quick look. The reason being is that they are low Qts drivers. This makes F3 high and very low Qtc, You can't get close to 0.5. Both of these drivers are better vented, but you still end up with a F3 too high. These are car drivers, not good HT drivers.

I would look at the JL audio line if you want to spend that much money.

For home HT if you go sealed you will need a big amp and an equalizer.

You really limit choices and performance with a 2 cu.ft. box. If you do that you will need a low sensitivity driver with high Qts and a huge amp and equalizer. There is the old adage, "Does a speaker have to be large? No but it really helps."

 

[WmAx]

OP: First off, forget RL-P. They are not even available until around mid 2010. They sold out a year ago - and TC Sounds is just getting back into production after bankruptcy. The RL-S, however, is still in stock, as most people never even realized it was a re-badged TC LMS ULTRA, otherwise they would have been long gone.

I must highly disagree with TLS; I say the RL-S is the PERFECT driver for sealed applications.

Natural response is irrelevant. You use a processor such as the Behringer DCX2496 to shape the response to your desire. The award winning top end JL Audio home subs use this very technique (The RL-S is superior to even JL's W7 drivers), as do most commercial sealed subs.

The RL-S's incredibly robust and linear motor is expressly intended for this type of application. However, you must not try to skimp on power. 1500-2000 RMS per driver is required for this technique to work well, at minimum.

You will get identical SQ at ANY volume level - very low to very high, with the RL-S driver. It's motor is the best/most linear in the world - no debate possible here. It is designed to withstand massive power with very little thermal compression. Thousands of watts are not a strain for these drivers. These are TC Sounds LMS drivers, rebadged to Sound Splinter, in name only.

You need to add oak 1" x 3" bracing ribs all around the interior of the pre-fab Dayton cabinets. This is not difficult. But it is needed with this driver - at high SPL - this driver will create enormous pressure in the box - possibly causing the enclosure to be damaged if you do not re-enforce it.

If you don't want to have to use so much power, and not have to use a processor to re-shape the response, then I will recommend building small ported cabinets using either the JL 10W7 or JL 8W7 drivers. While the W7 is not the equal of the TC LMS, the W7 is still one of the best drivers available, next to TC Sounds drivers. Do not mistake these for small SPL or low SQ. They are designed to optimize both. The 8", in the real world, bests most high quality 12" conventional subwoofers. The 10w7 will work superbly in the pre-fabbed 3 cubic foot PE cabinet, coupled with 3 x 3" diameter vents. Note: Do NOT dare attempt to use less port area - even 3 x 3" ports is not ideal. This 10" driver will equal most high quality conventional 15" subwoofers. The 8" operates ideally with about 450-500 watts RMS, and the 10" with about 650-750 watts RMS each.

-Chris

 

[adwilk]

The 10w7 will work superbly in the pre-fabbed 3 cubic foot PE cabinet, coupled with 3 x 3" diameter vents.
-Chris

Do you know off hand the optimum length of said ports?

 

[WmAx]

Do you know off hand the optimum length of said ports?

Around 36-38" in length each for the 3 x 3" ports for the 10W7 in a 3 cubic foot cabinet pre-fab. You will need to use 2 90 degree elbows per port. I recommend using PVC or ABS plumbing fixtures/pipe, as 'speaker parts specific' port parts may cost more. You will need to use some supports in the cabinet to hold the long ports at least at one additional point in the enclosure for stability. Do not concern yourself with flared ports. The flares don't mean much anyways, since the transition interior edges of the 90 degree elbows have rough edges.

-Chris

 

[adwilk]

Thanks, Chris.. I actually just found the answer in another of your posts. Much appreciated.

Just in case anybody is wondering about Chris's suggestions, I put together the Eclipse SW8200 for my parents with the prefab cab and oaudio 500 per Chris's recommendation and my parents absolutely love the thing. Very impressive sub for 400 or so I had in it. (already had the driver)

 

[WmAx]

Thanks, Chris.. I actually just found the answer in another of your posts. Much appreciated.

Just in case anybody is wondering about Chris's suggestions, I put together the Eclipse SW8200 for my parents with the prefab cab and oaudio 500 per Chris's recommendation and my parents absolutely love the thing. Very impressive sub for 400 or so I had in it. (already had the driver)

The 10W7 set I outlined would be even higher performance - a true premium level sub. But it must be assembled exactly as I described, added oak ribs and all.

-Chris

 

[adwilk]

The 10W7 set I outlined would be even higher performance - a true premium level sub. But it must be assembled exactly as I described, added oak ribs and all.

-Chris

I certainly figured it would be, and although I'm sure you don't need it, I figured I'd give you my endorsement.

 

[Warpdrv]

Hey Chris, I had led him in the direction of the LMS motor and the PE box and suggested he add bracing and maybe some stuffing with at least a EP2500 each for power.

These subs are not intended to be for HT.
MUSIC ONLY

I think that should get him into a driver that will be fantastic for years to come... Now the extra bonus is that he's only intending on using these drivers as dual subs for music. For right around $2K he'll have drivers that will best a pair of F112's

I don't have the modeling software up and running, could someone model this in the 2' and 3' PE cabinets for him to see what he's looking at for qtc.

$820 for LMS drivers
$350 for a pair of PE boxes
$500 pair of EP2500
$300 DCX 2496

$1970 well done...

 

[KEW]

I think you have some misconceptions.

No Doubt!

The characteristics you are looking for come down to Qtc. I think you are looking for a sealed sub with a Qtc somewhere in the neighborhood of 0.5.

Good to know. Is there a good link to an explanation of Qtc?

Neither of those two drivers are very promising for home HT. I have had a quick look. The reason being is that they are low Qts drivers. This makes F3 high and very low Qtc, You can't get close to 0.5. Both of these drivers are better vented, but you still end up with a F3 too high. These are car drivers, not good HT drivers.
I would look at the JL audio line if you want to spend that much money.

Thanks, I'll check into it.

For home HT if you go sealed you will need a big amp and an equalizer.

I have a DCX on the way, but this is for 100% music, so I am willing to sacrifice low and loud for SQ. So how big of an amp are we talking.

You really limit choices and performance with a 2 cu.ft. box. If you do that you will need a low sensitivity driver with high Qts and a huge amp and equalizer. There is the old adage, "Does a speaker have to be large? No but it really helps."

I realize that the box volume is a sacrifice, but if I am content with a max SPL of 95-100dB and a FR of 20Hz-120Hz, would it be practicable for the 2 cu. ft. size?

Thanks.

 

[lsiberian]

Good to know. Is there a good link to an explanation of Qtc?

http://www.carstereo.com/help/Articles.cfm?id=29

 

[KEW]

OP: First off, forget RL-P. They are not even available until around mid 2010. They sold out a year ago - and TC Sounds is just getting back into production after bankruptcy. The RL-S, however, is still in stock, as most people never even realized it was a re-badged TC LMS ULTRA, otherwise they would have been long gone.

Thanks! I had no idea on the RL-P.

I must highly disagree with TLS; I say the RL-S is the PERFECT driver for sealed applications.

Natural response is irrelevant. You use a processor such as the Behringer DCX2496 to shape the response to your desire. The award winning top end JL Audio home subs use this very technique (The RL-S is superior to even JL's W7 drivers), as do most commercial sealed subs.

The RL-S's incredibly robust and linear motor is expressly intended for this type of application. However, you must not try to skimp on power. 1500-2000 RMS per driver is required for this technique to work well, at minimum.

Is this true even with my objective of a max SPL of 95-100dB and a low end around 20Hz. If one does this, then the pair will have an eaasy time of doing what I would actually demand from them (75dB peaks is my norm. the 95dB is very liberal).
What kind of amp are we talking? The Yamaha P3500S specs at 2000W bridged into 4ohms, but that is at 1kHz and only for 20ms duration. I assume that is not the same as RMS Watts.

You will get identical SQ at ANY volume level - very low to very high, with the RL-S driver. It's motor is the best/most linear in the world - no debate possible here. It is designed to withstand massive power with very little thermal compression. Thousands of watts are not a strain for these drivers. These are TC Sounds LMS drivers, rebadged to Sound Splinter, in name only.

Wow,! It kind of sounds like using a jet fighter for crop dusting, but as long as the fine control is there, that is what I'm after.

You need to add oak 1" x 3" bracing ribs all around the interior of the pre-fab Dayton cabinets. This is not difficult. But it is needed with this driver - at high SPL - this driver will create enormous pressure in the box - possibly causing the enclosure to be damaged if you do not re-enforce it.

LOL, That would be too cool to rupture a box from sound pressure - but I don't think I'd ever want that much sound pressure in the same room I'm in. Nonetheless, I appreciate the need to keep cabinet resonance to a minimum and was thinking about running some unistrut (to maintain as much interior volume as possible) around the interior.

If you don't want to have to use so much power, and not have to use a processor to re-shape the response, then I will recommend building small ported cabinets using either the JL 10W7 or JL 8W7 drivers. While the W7 is not the equal of the TC LMS, the W7 is still one of the best drivers available, next to TC Sounds drivers. Do not mistake these for small SPL or low SQ. They are designed to optimize both. The 8", in the real world, bests most high quality 12" conventional subwoofers. The 10w7 will work superbly in the pre-fabbed 3 cubic foot PE cabinet, coupled with 3 x 3" diameter vents. Note: Do NOT dare attempt to use less port area - even 3 x 3" ports is not ideal. This 10" driver will equal most high quality conventional 15" subwoofers. The 8" operates ideally with about 450-500 watts RMS, and the 10" with about 650-750 watts RMS each.
-Chris

Thanks for your input!

 

[Warpdrv]

A pair of EP 2500's should be plenty of amp for you for this project, and seeing as your not looking to troll the depths, even better... Dual amps will put those 12" drivers easily over 100db in room... trust me, your speakers won't be able to keep up with what you will have in Sub capabilities...

I am running the EP2500 bridged for a 15" TC 3000 and it works out great for that driver, thats the AXIS driver that ParadigmDAWG is running for his as well.


And the best part is that the RL-s12 is a 4ohm single voice coil, nice easy hookup for you...

 

[lsiberian]

A pair of EP 2500's should be plenty of amp for you for this project, and seeing as your not looking to troll the depths, even better... Dual amps will put those 12" drivers easily over 100db in room... trust me, your speakers won't be able to keep up with what you will have in Sub capabilities...

I am running the EP2500 bridged for a 15" TC 3000 and it works out great for that driver, thats the AXIS driver that ParadigmDAWG is running for his as well.


And the best part is that the RL-s12 is a 4ohm single voice coil, nice easy hookup for you...

I'd still like to port one of those puppy's. But Wmax cussed when I tossed the idea out there.

 

[ParadigmDawg]

What do you mean? He designed a ported one for me.

I'd still like to port one of those puppy's. But Wmax cussed when I tossed the idea out there.

 

[WmAx]

Is this true even with my objective of a max SPL of 95-100dB and a low end around 20Hz. If one does this, then the pair will have an eaasy time of doing what I would actually demand from them (75dB peaks is my norm. the 95dB is very liberal).

Let's say you provided 1500-2000 RMS to each one as I specified in the sealed cabinets, as I specified. It would be no problem to hit 115-120dB in your actual room at levels at 20Hz, and 125-130dB at 30Hz, even with the sealed set up. Or you can run them at 60dB peaks. They will have the capability for extreme dynamics, with no audible change in SQ.

Try to ignore that you won't often use this full capability - the point is that you have it available for whenever you may need it, and having this much headroom ensures that the drivers operate well within their linear range, with no compression or distortion. You are in fact future proofing your set up to have the highest fidelity and dynamic capability for ANY future application. These subs will positively augment virtually any high performance/high end main speakers in the world.

What kind of amp are we talking? The Yamaha P3500S specs at 2000W bridged into 4ohms, but that is at 1kHz and only for 20ms duration. I assume that is not the same as RMS Watts.

The Yamaha amps are not intended to operate mono bridged into 4 Ohm loads. They are intended for 4 Ohms in stereo. The most powerful Yamaha in this P series is the P7000s, which provides roughly 950 watts RMS, 20Hz-20,000Hz, 4 Ohms, both channels driven. You could get away with this for apartment use - and if it was a ported set up - it would be just fine. The problem is the very large gain that must be applied to correct on the lowest octave to get the extension you desire in the small sealed box. You really need larger amplification to do this and ensure no amplifier clipping/problems. If you would be willing to use the RL-S, configured in the sealed boxes to be flat to say 25-28 Hz instead of 18-20Hz, then a single Yamaha P7000S would actually be just fine to run 2 of the subs, and handle large dynamics, no problem. Later on, you could decide to go to larger amps to get dynamic capability down to 20Hz flat response, if you so desire it.

-Chris

 

[KEW]

Try to ignore that you won't often use this full capability - the point is that you have it available for whenever you may need it, and having this much headroom ensures that the drivers operate well within their linear range, with no compression or distortion. You are in fact future proofing your set up to have the highest fidelity and dynamic capability for ANY future application. These subs will positively augment virtually any high performance/high end main speakers in the world.

Great, future proofing is my ideal!
I am quite content with my current speakers and haven't heard anything to justify spending more. They are very good to my ear. However, I am waiting to hear the speakers that outright stun me with realistic sound! If and when, I don't want to start second-guessing my subs.

The Yamaha amps are not intended to operate mono bridged into 4 Ohm loads. They are intended for 4 Ohms in stereo. The most powerful Yamaha in this P series is the P7000s, which provides roughly 950 watts RMS, 20Hz-20,000Hz, 4 Ohms, both channels driven. You could get away with this for apartment use - and if it was a ported set up - it would be just fine. The problem is the very large gain that must be applied to correct on the lowest octave to get the extension you desire in the small sealed box. You really need larger amplification to do this and ensure no amplifier clipping/problems. If you would be willing to use the RL-S, configured in the sealed boxes to be flat to say 25-28 Hz instead of 18-20Hz, then a single Yamaha P7000S would actually be just fine to run 2 of the subs, and handle large dynamics, no problem. Later on, you could decide to go to larger amps to get dynamic capability down to 20Hz flat response, if you so desire it.
-Chris

This sounds like a good option, and it would be nice to match the P3500S. My use is not apartment though. My room is 17' X 23' X 12' (vaulted ceiling). Is that too big?
What would be a good recommendation for an amp of similar or better stereo 4ohm performance, but could later run as bridged mono?

 

[TLS Guy]

I wandered into a site that had the wrong TS parameters for that driver last night. It is in fact a very high Qts driver. The attached graphs shows the driver in a 2 cu. ft. and 4.5 cu.ft. sealed cabinet. Frequency response extends very slightly in the larger box. The biggest change is that Qtc drops to 0.817.

So the system is not highly damped. If a small enclosure is a must with enough power this driver can be equalized to the 20 Hz easily. Sensitivity is very low, so lots of amp horse power required.

Name: RL-s12
Type: Standard one-way driver
Company: Soundsplinter
No. of Drivers = 1
Fs = 30.97 Hz
Qms = 7.459
Vas = 27.65 liters
Cms = 0.0767 mm/N
Mms = 344.2 g
Rms = 9.097 kg/s
Xmax = 38.5 mm
Xmech = 57.75 mm
P-Dia = 254.1 mm
Sd = 507 sq.cm
P-Vd = 1.952 liters
Qes = 1.114
Re = 2.88 ohms
Le = 2.54 mH
Z = 3 ohms
BL = 13.5 Tm
Pe = 2000 watts
Qts = 0.97
no = 0.0711 %
1-W SPL = 80.66 dB
2.83-V SPL = 80.5 dB
-----------------------------------------
Box Properties
Name:
Type: Closed Box
Shape: Prism, square
Vb = 2 cu.ft
Qtc = 0.889
F3 = 32.09 Hz
Fill = heavy

Name: RL-s12 3ohm
Type: Standard one-way driver
Company: Soundsplinter
No. of Drivers = 1
Fs = 30.97 Hz
Qms = 7.459
Vas = 27.65 liters
Cms = 0.0767 mm/N
Mms = 344.2 g
Rms = 9.097 kg/s
Xmax = 38.5 mm
Xmech = 57.75 mm
P-Dia = 253.3 mm
Sd = 507 sq.cm
P-Vd = 1.94 liters
Qes = 1.114
Re = 2.88 ohms
Le = 2.54 mH
Z = 3 ohms
BL = 13.5 Tm
Pe = 2000 watts
Qts = 0.97
no = 0.0711 %
1-W SPL = 80.66 dB
2.83-V SPL = 80.5 dB
-----------------------------------------
Box Properties
Name:
Type: Closed Box
Shape: Prism, square
Vb = 4.5 cu.ft
Qtc = 0.817
F3 = 31.03 Hz
Fill = heavy

 

[WmAx]

Great, future proofing is my ideal!
I am quite content with my current speakers and haven't heard anything to justify spending more. They are very good to my ear. However, I am waiting to hear the speakers that outright stun me with realistic sound! If and when, I don't want to start second-guessing my subs.


This sounds like a good option, and it would be nice to match the P3500S. My use is not apartment though. My room is 17' X 23' X 12' (vaulted ceiling). Is that too big?
What would be a good recommendation for an amp of similar or better stereo 4ohm performance, but could later run as bridged mono?

No, that room is not too large. The speakers will outright break your drywall if you want to do that.

Again, if 25Hz or so response is sufficient, the P7000S is really all you need. You still need to use a Behringer DCX2496 or comparable device, of course.
Any other, larger amp, you will likely have to do the fan swap. A Behringer EP2500 per speaker is ideal bridged. About 2000 clean watts per driver. But you have to do the fan mods, and don't forget you need a 20 AMP 120V circuit for EACH of the EP2500 amplifiers if you actually want a chance to get anywhere near their actual power capability in actual use. The P7000S is sufficient if you are happy with flat 25Hz response - and the P7000S is also extremely energy efficient.

-Chris

 

[KEW]

I wandered into a site that had the wrong TS parameters for that driver last night. It is in fact a very high Qts driver. The attached graphs shows the driver in a 2 cu. ft. and 4.5 cu.ft. sealed cabinet. Frequency response extends very slightly in the larger box. The biggest change is that Qtc drops to 0.817.

Thanks for modeling at both sizes. The lack of difference is surprising (and reassuring, since I am committed to the small size). I guess the efficiency is reasonably close to the JL Audio Fathom F112 with it's 1500W RMS amp.

So the system is not highly damped. If a small enclosure is a must with enough power this driver can be equalized to the 20 Hz easily. Sensitivity is very low, so lots of amp horse power required.

Apparently, one of my misconceptions is that a sealed speaker is well damped!
I think I'll be getting what I want despite the small size, but, to lessen my ignorance, would porting or increased size improve damping?
Thanks,
Kurt