The Eminence Lab12 has proven itself worthy in a variety of low-tuned PA applications. This venerable driver has held up well and is still a good candidate for many types subwoofer designs.
The Lab12 has been been around for a while and had been used in bass reflex, tapped horn, and front loaded horn alignments, so I propose a shoot-out of some of these Lab12 designs. Let's not get nasty. What is ideal for one person might not work for another, so please keep an open mind.
One of DIYaudio.com's elder statesmen, weltersys, has two proven designs that I submit for the first-round smack down.
In one corner we have the weltersys Keystone Sub, a tapped horn that is very adaptable:
http://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers.html
They Keystone Sub is a big fella (45" tall x 26.5" wide x 22.5" deep), but loaded with two Lab12's goes low and LOUD. This is the grey race on the graph below.
In the other corner we have the weltersys Dual Lab12 bass reflex design:
FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems
The Dual Lab12 is tiny little fella (22.5" high x 26.5" wide x 22.5" deep) - half the size of the Keystone Sub. It goes just as low as the Keystone, but not as loud. This is the blue trace on the graph below.
So, if you needed a subwoofer that went really low and load, which of these designs would you build, and WHY? What are the pro's/con's you see of each design.
Let's keep things civil. I personally think these are both excellent designs - one of my biggest arguments would be size and portability.
The Lab12 has been been around for a while and had been used in bass reflex, tapped horn, and front loaded horn alignments, so I propose a shoot-out of some of these Lab12 designs. Let's not get nasty. What is ideal for one person might not work for another, so please keep an open mind.
One of DIYaudio.com's elder statesmen, weltersys, has two proven designs that I submit for the first-round smack down.
In one corner we have the weltersys Keystone Sub, a tapped horn that is very adaptable:
http://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers.html
They Keystone Sub is a big fella (45" tall x 26.5" wide x 22.5" deep), but loaded with two Lab12's goes low and LOUD. This is the grey race on the graph below.
In the other corner we have the weltersys Dual Lab12 bass reflex design:
FREE SUB PLAN: Dual Lab12 (Front Loaded) by Welter Systems
The Dual Lab12 is tiny little fella (22.5" high x 26.5" wide x 22.5" deep) - half the size of the Keystone Sub. It goes just as low as the Keystone, but not as loud. This is the blue trace on the graph below.
So, if you needed a subwoofer that went really low and load, which of these designs would you build, and WHY? What are the pro's/con's you see of each design.
Let's keep things civil. I personally think these are both excellent designs - one of my biggest arguments would be size and portability.
Attachments
Another shape option with similar LF would be MSGR's:
http://www.diyaudio.com/forums/subwoofers/232219-325-lab-12-based-pa-tapped-horn-35hz-extension.html
The Keystone could be split in half vertically and occupy the same volume as the BR, so the size and portability option is there.
A single 12 also could be folded in to the BR shape, though would loose a little volume as it would need more folds than the Keystone or IPal design.
With a single driver TH cabinet having similar LF output, and more upper level than the dual ported using twice the power, the only thing the ported cabinet has going for it is it may not need the tops delayed to time/phase align a system, while the TH need tops typically delayed around 7ms.
Since almost any DSP has delay options, that difference would only apply to those using analog crossovers.
The BR can also be used with a single cone if you like a "haystack" LF response, the comparison at the same drive level between the single and dual load below. The single has almost the same output at 40 Hz as the dual, but has 6 dB less headroom in the upper "kick" region.
If anyone wants a pair of the WS BR cabinets, PM me.
Art
http://www.diyaudio.com/forums/subwoofers/232219-325-lab-12-based-pa-tapped-horn-35hz-extension.html
The Keystone could be split in half vertically and occupy the same volume as the BR, so the size and portability option is there.
A single 12 also could be folded in to the BR shape, though would loose a little volume as it would need more folds than the Keystone or IPal design.
With a single driver TH cabinet having similar LF output, and more upper level than the dual ported using twice the power, the only thing the ported cabinet has going for it is it may not need the tops delayed to time/phase align a system, while the TH need tops typically delayed around 7ms.
Since almost any DSP has delay options, that difference would only apply to those using analog crossovers.
The BR can also be used with a single cone if you like a "haystack" LF response, the comparison at the same drive level between the single and dual load below. The single has almost the same output at 40 Hz as the dual, but has 6 dB less headroom in the upper "kick" region.
If anyone wants a pair of the WS BR cabinets, PM me.
Art
Attachments
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Art, some good points there in support of both designs. From my angle it looks like they both got some good punches in, but the Keystone is looking a bit stronger. Personally, I am favoring the single-width Keystone as my choice, unless someone can convince me otherwise.
And yes, I am familiar with MSGR's Lab12 design, it will entering the ring in a future battle. I actually have quite a few contenders lined up to get in the ring. Thanks for you comments.
I think we need some "rules" for this battle.
For example:
1. Sim'd F3 should not be more than 40 Hz
2. Sim'd sensitivity efficiency @40 Hz should not be less than 96dB/2.83V/1M
3. Bandwidth must extend up to at least 100 Hz, -3dB
FWIW, I looked at the LAB12 as a possible TH candidate some time ago, but I found Fs a bit too low (I think TD suggested that for best results the Fs should be some way within the passband, suggesting that for a 40 Hz TH you should be looking for drivers with Fs around 50 Hz...)
For example:
1. Sim'd F3 should not be more than 40 Hz
2. Sim'd sensitivity efficiency @40 Hz should not be less than 96dB/2.83V/1M
3. Bandwidth must extend up to at least 100 Hz, -3dB
FWIW, I looked at the LAB12 as a possible TH candidate some time ago, but I found Fs a bit too low (I think TD suggested that for best results the Fs should be some way within the passband, suggesting that for a 40 Hz TH you should be looking for drivers with Fs around 50 Hz...)
Hi DHAA,
Just a quick question: how do you suggest we compare a design to the keystone sub? I still maintain, that the Keystone sub cannot be simulated in Hornresp. I like Art's contributions of measurements, etc. a lot, but I can't compare them to Hornresp simulations that have not been build and measured (preferably by Art)
Regards,
Just a quick question: how do you suggest we compare a design to the keystone sub? I still maintain, that the Keystone sub cannot be simulated in Hornresp. I like Art's contributions of measurements, etc. a lot, but I can't compare them to Hornresp simulations that have not been build and measured (preferably by Art)
Regards,
^exactly a true shoot out should be done the way traditional sub shoot outs are. Controlled environment (well same exact test conditions and location, same test mic etc) and unbiased data recorded.
I only have a minidsp umik. It has yet to be calibrated by CSL, but eventually I'll get around to it and take more measurements of my PAL12.
I only have a minidsp umik. It has yet to be calibrated by CSL, but eventually I'll get around to it and take more measurements of my PAL12.
Mr. Steele, tb46, and MrgSr - thanks for you comments. I realize this will not be a completely fair way to compare the various designs, as a side-by-side test would be virtually impossible. What I am interested in is a discussion of the pro's/con's of each, and why someone would choose a particular one over another.
If Art has accurate measurements but no HR sim, then that is what we judge it on. If mRgSr has a decent HR sim, but possibly flawed measurements, then that is what we judge it on. I think most of you know enough about speaker design to make a fairly accurate judgement with the facts your are presented with.
A mobile DJ may have a bias for smaller BR cabs. A fixed install club owner might prefer a mega horn. I would like to hear people rationalize their choices.
I think my title "Smack Down/Death Match" might have been a little too drastic. My sons have been addicted to MMA lately and I think it has rubbed off on me a bit. I don't want this to turn into a nasty slugfest - I would hope everyone would be respectful of others needs and opinions. I would just like to hear others thoughts on these various designs.
When Art mentioned cutting his Keystone in half to increase portability, I truly had not considered that, and that is a definite bonus for me. I am sure there are many points that I and others have not considered, so let's hear them.
Mr. Steele, the guidelines you mentioned are fine with me - they all sound pretty reasonable. But if something is just a hair off of that, I say let it slide. Maybe just ding it a bit for whatever deficiencies it has and see if it has some other aspects that can make up for it?
If Art has accurate measurements but no HR sim, then that is what we judge it on. If mRgSr has a decent HR sim, but possibly flawed measurements, then that is what we judge it on. I think most of you know enough about speaker design to make a fairly accurate judgement with the facts your are presented with.
A mobile DJ may have a bias for smaller BR cabs. A fixed install club owner might prefer a mega horn. I would like to hear people rationalize their choices.
I think my title "Smack Down/Death Match" might have been a little too drastic. My sons have been addicted to MMA lately and I think it has rubbed off on me a bit. I don't want this to turn into a nasty slugfest - I would hope everyone would be respectful of others needs and opinions. I would just like to hear others thoughts on these various designs.
When Art mentioned cutting his Keystone in half to increase portability, I truly had not considered that, and that is a definite bonus for me. I am sure there are many points that I and others have not considered, so let's hear them.
Mr. Steele, the guidelines you mentioned are fine with me - they all sound pretty reasonable. But if something is just a hair off of that, I say let it slide. Maybe just ding it a bit for whatever deficiencies it has and see if it has some other aspects that can make up for it?
I don't think there's been a DIY version yet, but the Danley CS30 appears to use a lab 12 driver (or custom eminence 12" based on the lab12) and also meets the criteria.
http://www.danleysoundlabs.com/products/subwoofers/specialty-subs/cs30/#slide3
(Well 95db/2.83v/1m..close enough to 96)
http://www.danleysoundlabs.com/products/subwoofers/specialty-subs/cs30/#slide3
(Well 95db/2.83v/1m..close enough to 96)
First, let me state what I prefer in a subwoofer:
- I prefer a fairly flat frequency response. Heavy EQ and the phase shift associated with it just doesn't sound good to me.
- If I had to choose between portability and high SPL, portability would win. If I needed even higher SPL, I would prefer to bring more smaller cabs to the show. The additional cost would not be a major concern to me.
- I would be very happy with decent response down to 40 Hz, but I really don't require much below that. I don't need the overhyped or super extended low-end, just an accurate representation of normal music. I don't need my guts rattled.
Keystone - Frequency response is decent - It would take some EQ but nothing drastic. The originally stated size of this cabinet was borderline too large for my needs. But when Art mentioned making it half width with just one driver, that really appealed to me. I would enjoy experimenting with the Keystone hole to see what kind of results I would get.
Dual Lab12 - This has the perfect frequency response for me - just a slight downward slope as frequency rises. I like the fairly compact size. The main drawback on this one is the need for some serious power amps to push this design.
Conclusion: I would be very happy with either of these designs. If I had to choose, I would probably go with 2 or 4 of the single-driver/half-width Keystones. And since Art himself appears to have abandoned his Dual Lab12's in favor of his Keystones (and since he knows more about this than I ever will) I guess I would follow his lead and go Keystone myself.
- I prefer a fairly flat frequency response. Heavy EQ and the phase shift associated with it just doesn't sound good to me.
- If I had to choose between portability and high SPL, portability would win. If I needed even higher SPL, I would prefer to bring more smaller cabs to the show. The additional cost would not be a major concern to me.
- I would be very happy with decent response down to 40 Hz, but I really don't require much below that. I don't need the overhyped or super extended low-end, just an accurate representation of normal music. I don't need my guts rattled.
Keystone - Frequency response is decent - It would take some EQ but nothing drastic. The originally stated size of this cabinet was borderline too large for my needs. But when Art mentioned making it half width with just one driver, that really appealed to me. I would enjoy experimenting with the Keystone hole to see what kind of results I would get.
Dual Lab12 - This has the perfect frequency response for me - just a slight downward slope as frequency rises. I like the fairly compact size. The main drawback on this one is the need for some serious power amps to push this design.
Conclusion: I would be very happy with either of these designs. If I had to choose, I would probably go with 2 or 4 of the single-driver/half-width Keystones. And since Art himself appears to have abandoned his Dual Lab12's in favor of his Keystones (and since he knows more about this than I ever will) I guess I would follow his lead and go Keystone myself.
Sine143, I think we have enough evidence there to make a reasonable comparison, especially since the first slugfest is between two of his own designs - that he did the actual measurements for both on. And you even could pull of Eminence's Lab12 design sheet to see what they get out of a ported cab of similar size, and use that as an additional reference for comparisons sake. I think the increase he got in SPL out of his Keystone design is pretty impressive, comparatively speaking, and I think his data shows that.
1) EQ generally corrects phase shifts associated with a design's frequency response deviation, the phase response after EQ is almost always flatter than before.
2) I find the full size Keystone easier to move than the half size BR cabinets.
The Domino DFLH, which is about the size of a vertically cut in half Keystone, is so thin it can be a problem (tippy, hence the name) on a two wheeler on uneven surfaces.
Unlike the 2x12" BR, you can't haul two tall skinny cabinets on a two wheeler at once.
Multiple smaller cabs always impose a weight penalty, and tall thin ones can't be stacked on vertically without using a plinth and ratchet straps for safety.
3)Better to have it and not use it, than to not have it and (have your kids and grand kids) miss it
. I have another 2x Lab 12", the "Bowtie", a 26.5 x 22.5 x 15" bandpass sub that makes 40 Hz, but it just didn't cut it for me, so I never bothered to post it.
4) You stated in #2 "The additional cost would not be a major concern to me".
There are drivers that are far better than the Lab 12 available some 14 years after it was introduced, even in terms of dollar per output, especially if a 40 Hz F3 is all you want.
I have experimented and shared designs that work well with the Lab 12 because I already owned them, and they do remain a decent value, and have a proven track record.
Having recycled the drivers through many designs, and compared them to better drivers now available, I probably won't be purchasing more of them.
Art
I've been a lurker on DIY Audio for a long time, finally decided to sign up and post.
The picture of the Dual Lab 12 BR is a picture of my construction, I was actually quite proud of my achievement as it was my second speaker build - the first being a BFM T30 that fell short of expectations. I'm up to four cabs now, added a few tweaks to existing cabs over time including caster boards, feet and pole mounts but I'm not sure I'm going to go past four cabs.
The cabs sound great, material cost is fairly low and the build is straightforward, I'd recommend this build for anybody that needs to get their feet wet in speaker building. I'd also recommend this build for anybody that needs low extension but doesn't need high SPL, a pair with SRX715 on top for a Jazz gig with approx 150 ppl really allowed these cabs to shine, the Labs reproduced the stand up bass better (the lampy sitting next to me even commented on the difference) than the SRX718s that had been used previously.
Originally I ran a cab per channel on an iTech 6000, the iTech at full tilt was able to push these cabs past their limit. I now wire each cab in series and run a pair of cabs per channel of the 6000, I can push the amp right into clipping and the drivers don't show any signs of distress. An iTech 8000 might drive 4 drivers to their full potential, but I don't mind the bit of headroom running this configuration.
Currently waiting on a pair of 18TBW100s to arrive, I've been working on a Dual 18 BR that is... large, two 7.05 cu. ft. chambers tuned to 32Hz, each cone powered off of a channel of the iTech 6000. About 33% smaller than a Lab Sub but larger than a pair of Art's Keystone subs, slightly larger than a SRX728 but with more truck pack friendly dimensions.
I've drawn the box up in Sketch Up, modelled it in WinISD and tweaked the dimensions by calculating nominal box volume in Excel. I'd like to get some input, I will create a new thread in a few days.
Worst case: The box gets the thumbs down from some vets on the forum, and I start looking at TH18s of Keystones again.
The picture of the Dual Lab 12 BR is a picture of my construction, I was actually quite proud of my achievement as it was my second speaker build - the first being a BFM T30 that fell short of expectations. I'm up to four cabs now, added a few tweaks to existing cabs over time including caster boards, feet and pole mounts but I'm not sure I'm going to go past four cabs.
The cabs sound great, material cost is fairly low and the build is straightforward, I'd recommend this build for anybody that needs to get their feet wet in speaker building. I'd also recommend this build for anybody that needs low extension but doesn't need high SPL, a pair with SRX715 on top for a Jazz gig with approx 150 ppl really allowed these cabs to shine, the Labs reproduced the stand up bass better (the lampy sitting next to me even commented on the difference) than the SRX718s that had been used previously.
Originally I ran a cab per channel on an iTech 6000, the iTech at full tilt was able to push these cabs past their limit. I now wire each cab in series and run a pair of cabs per channel of the 6000, I can push the amp right into clipping and the drivers don't show any signs of distress. An iTech 8000 might drive 4 drivers to their full potential, but I don't mind the bit of headroom running this configuration.
Currently waiting on a pair of 18TBW100s to arrive, I've been working on a Dual 18 BR that is... large, two 7.05 cu. ft. chambers tuned to 32Hz, each cone powered off of a channel of the iTech 6000. About 33% smaller than a Lab Sub but larger than a pair of Art's Keystone subs, slightly larger than a SRX728 but with more truck pack friendly dimensions.
I've drawn the box up in Sketch Up, modelled it in WinISD and tweaked the dimensions by calculating nominal box volume in Excel. I'd like to get some input, I will create a new thread in a few days.
Worst case: The box gets the thumbs down from some vets on the forum, and I start looking at TH18s of Keystones again.
Spenser (sorry op this is OT), your BR box loaded with the 18tbw100s sounds very similar to the PK sound cx800 discussed in this thread (http://www.diyaudio.com/forums/subw...ol-horn-vs-modern-vented-box.html#post3794017)
roughly 320 liters, (45x22.5x30), 700 square inch center slot port, about 45 to 50 cm in lenght.
roughly 320 liters, (45x22.5x30), 700 square inch center slot port, about 45 to 50 cm in lenght.
Spenser,
In terms of gross volumes (exterior size) the WS 2x12 is 7.76 cubic feet, the Keystone is double that, 15.53, the JBL SRX 728 is 19, and the LabSub 26.36.
If your BR is larger than a pair of Keystones, it would be larger than a LabSub. That does not sound like what you are planning.
If it is between the Keystone and SRX 728 size (as would be implied by two 7.05 cu. ft. chambers), but tuned lower (32 Hz compared to around 36 for the Keystone) the dual 18TBW100 will require double the power (and cones) to go almost as loud as the Keystone.
The dual 18TBW100 will probably still go slightly louder than the SRX 728, as the Xmax potential is greater.
In my comparison of a single BC loaded BR (larger per cone than your net box size) compared to the Keystone, the BR at full power lost a few dB of LF due to port compression.
What are the port dimensions (per driver) you are considering?
Art
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I'm familiar with the CX800, I guess there is only so many ways to make a low tuned, high power dual 18 in a truck pack friendly format.
Are you sure about the 700 square inch? Where would they fit that on the baffle?
You are correct, must have been late because I under calculated the size of two Keystones and over calculated the size of a LabSub.
Here in lies my eternal debate, it will cost twice as much money (more drivers and more amps) and substantially more pack space to - possibly - gain 4 or 5Hz of extension, and I still might be down a few dB in max output.
Is it worth it?
Some time with Audacity and my music library tells me that for 90% of it, probably not as most of the heavy dance music is in the 35-50Hz range, but there is that 10% that shows significant content in the 30-35Hz area.
The 728 is a box I'm quite familiar with, so I always try to reference back to that box when doing comparisons.
I have two proposed port designs for the box I've been toying with, the first in 4x4" round ports which looked good in WinISD in terms of vent mach, but I worry about port compression. The second idea is 4 corner ports with base ~10.5" and height ~5.25". Note that both port designs are per driver, so in both cases 8 ports all together.
I really want to make a new thread to avoid derailing this one any further, this week I'm in rehearsals for a musical production so I'm working 9:30am to 12:00am most days. I'm actually typing this as I eat some Chinese food (that's a good bedtime snack right?), I'll try to get all my drawings together and post something sometime this week when I have a spare moment.