What are the suggestions for high quality small 12" closed subs?
For a long time I have had interest in trying a 4 sub setup as proposed by Geddes/Welti//etc.
My interest is music exclusively (not HT).
The subs should cross at 80Hz over to 15 inch "low-mids" (Altecs), which are crossed at about 700Hz to a horn with a compression driver.
I am not looking for extreme low frequency reproduction, but the lower they go, the better. SPL should be enough to keep up with the Altec+horn.
Finally, the subwoofer enclosures should remain small, I'd say below 90l/3cft, and closed boxes are preferred.
The LAB12 seems to do the job, but I am not sure if there are better alternatives.
For a long time I have had interest in trying a 4 sub setup as proposed by Geddes/Welti//etc.
My interest is music exclusively (not HT).
The subs should cross at 80Hz over to 15 inch "low-mids" (Altecs), which are crossed at about 700Hz to a horn with a compression driver.
I am not looking for extreme low frequency reproduction, but the lower they go, the better. SPL should be enough to keep up with the Altec+horn.
Finally, the subwoofer enclosures should remain small, I'd say below 90l/3cft, and closed boxes are preferred.
The LAB12 seems to do the job, but I am not sure if there are better alternatives.
You don't indicate a playback level you expect the subs to keep up with. Are you a 2 watt tube kind of person or more of a peel the paint off the walls/rock concert playback level person?
And when you say you want them to keep up, do you mean from a sensitivity standpoint or just an SPL standpoint? Are you happy using a high power amp on a high excursion sub or would you prefer a different approach?
And when you say you want them to keep up, do you mean from a sensitivity standpoint or just an SPL standpoint? Are you happy using a high power amp on a high excursion sub or would you prefer a different approach?
Dunno, don't keep up with the latest n' greatest drivers, but the LAB 12C @ ~ 88 dB/m/80 Hz/2pi + ~ 12 dB for (4) = ~100 dB base eff., so typically > than a stereo pair of Altec 15" and ignoring any room/boundary gain still ~ 88 dB/20 Hz in 3 ft^3/~0.5 Qtc for optimal transient response.
Mattstat, your description made me laugh 😆, I believe I am somewhat in between. I do raise the volume up every now and then, I guess to something around 90-95 dB or perhaps a bitr more every now and then (continuous). When speaking form the subs keeping up with the mains I meant SPL. Subs will have their own apm(s), but no extra DSP on them (á la "swarm" subs)
GM, I had not thought of the "C" version. Any advantages over the normal one (other than smaller boxes, and... the possibility to hook two in parallel @ 6.2 ohm... which I had not thought before!.... so actually, two big pluses on the C version)? I had thought of 0.577-0.6 Qtc as a compromise to keep the boxes smaller. The "c" would need a 95 l enclosure at 0.5, 60 l @ t 0.577, and 10 liters less at 0.6.
According to Vituix, the Labs runs out of xmax at 20Hz with 150w (0.577 QTC), and 100w @ 0.5 Qtc.
GM, I had not thought of the "C" version. Any advantages over the normal one (other than smaller boxes, and... the possibility to hook two in parallel @ 6.2 ohm... which I had not thought before!.... so actually, two big pluses on the C version)? I had thought of 0.577-0.6 Qtc as a compromise to keep the boxes smaller. The "c" would need a 95 l enclosure at 0.5, 60 l @ t 0.577, and 10 liters less at 0.6.
According to Vituix, the Labs runs out of xmax at 20Hz with 150w (0.577 QTC), and 100w @ 0.5 Qtc.
I haven't run the numbers to compare them all, but these could be interesting depending on your goals and budget. Eminence makes nice drivers also, but in general I would expect these to be a little more refined. Being a pro driver, the Eminence may be more durable though. If you're going to push things hard that might be more important than a little more finesse.
I haven't used these particular drivers, but I tried a smaller one from the Peerless NE line and liked it (and the basket looks like an alien spaceship, so that's a plus). I've also used a 10" ScanSpeak aluminium cone woofer sealed and liked it quite a bit. That was running up to about 400 Hz though, so different application than yours.
https://www.parts-express.com/Peerless-NE315W-08-12-Subwoofer-Speaker-264-1142
https://www.madisoundspeakerstore.c...835017-xxls-12-aluminum-cone-subwoofer-4-ohm/
https://www.madisoundspeakerstore.c...s/scanspeak-discovery-30w/4558t-12-subwoofer/
I haven't used these particular drivers, but I tried a smaller one from the Peerless NE line and liked it (and the basket looks like an alien spaceship, so that's a plus). I've also used a 10" ScanSpeak aluminium cone woofer sealed and liked it quite a bit. That was running up to about 400 Hz though, so different application than yours.
https://www.parts-express.com/Peerless-NE315W-08-12-Subwoofer-Speaker-264-1142
https://www.madisoundspeakerstore.c...835017-xxls-12-aluminum-cone-subwoofer-4-ohm/
https://www.madisoundspeakerstore.c...s/scanspeak-discovery-30w/4558t-12-subwoofer/
I'm currently running 2 sealed subs, each with 2x original LAB12's below my 15" midbass horns. The room is 20' x 10'. For music only at very loud domestic levels I have no complaints. If I was building them again I would do them as push push loaded boxes to lower cabinet vibration.
Have you considered the Dayton Audio UM12-22? This would work well in 3cuft and give you about Q=0.75 and F3=30 Hz.
Any subwoofer driver will probably have a lower efficiency than your 15" low mid. For example the UM12-22 comes in around 87dB@2.83V/1m. With your chosen max enclosure volume, Hoffman's Iron Law is constraining you here.
Charlie, I appreciate your input!
With the LAB (non C) I am getting an F3 of 34 Hz using a Linkwitz transform starting with a Qtc=1.0 box. Because I will be using 4 subs, very few watts would be enough with each, and I have no efficiency constraints because I will be using a separate amp. As GMs calculation above shows, I would have a very high base sensitivity at 80Hz.
The UM12 has twice the MMS and would have similar F3, F6 and F10 as the Lab with the transform, but would need a much larger box (the enclosure for the Lab Qtc=1.0 box is really small at 20l).
Would you see any disadvantages to use the transform in my case?
I am playing with Vituix and getting all these numbers out of it. (even the transform's circuit parameters). I don't know how well I am using this marvellous tool!
With the LAB (non C) I am getting an F3 of 34 Hz using a Linkwitz transform starting with a Qtc=1.0 box. Because I will be using 4 subs, very few watts would be enough with each, and I have no efficiency constraints because I will be using a separate amp. As GMs calculation above shows, I would have a very high base sensitivity at 80Hz.
The UM12 has twice the MMS and would have similar F3, F6 and F10 as the Lab with the transform, but would need a much larger box (the enclosure for the Lab Qtc=1.0 box is really small at 20l).
Would you see any disadvantages to use the transform in my case?
I am playing with Vituix and getting all these numbers out of it. (even the transform's circuit parameters). I don't know how well I am using this marvellous tool!
In the past I was more excited about using the LT to make a driver in a smaller box act like a larger one. It's definitely a useful tool for CB subs, but now I prefer bit more conservative approach that still uses the LT but with the driver in a larger box. I try to design the box to give a Q=0.7 or less for the un-equalized response, which requires a larger box volume. This has a few subtle effects. The first is that smaller boxes imply higher distortion because the air-spring effect is different on the in-stroke and the out-stroke. When Sd*Xmax is not much less than Vb, you can create a few extra percent of distortion from this effect at high excursions. Also, for a given SPL, a larger box will require less power or power lift to achieve it. It's possible to set yourself up for failure because you need in the kW range of power to actually push the driver to Xmax, and that is just not realistic for home audio. Keep in mind that Q and F change as a function of excursion due to various non-linearities, typically both increasing. When you start with Q>0.7 or so I do not like the SQ as much as when the box is larger and when for example Q=1 the LT will not do a good job of compensating for the response at all power levels. IMO this leads to muddy bass. This seems to be less of a problem when Q<0.7 or so because the LT EQ curve is more of a gradual rise in power. Anyway, that's my 2 cents worth.
Charlie, thank you, that is very, very helpful!
With a Qtc of 0.6 the volume is around 80l for the LAB (54L on the Lab12c) , still less of the 100l I get for .707 on the Seas.
Would you see a Qtc of 0.6 as a good starting point for the LT? Your comment makes me feel 0.7 may still be high, and the 12C still has a small box with 0.6. Is 0.6 with LT still a compromise in your view?
Regarding Fp/Qp, are there any things/limits I should be aware of other than Xmax (in my case I am WAY below the drivers Pmax for the needed SPL per driver)?
With a Qtc of 0.6 the volume is around 80l for the LAB (54L on the Lab12c) , still less of the 100l I get for .707 on the Seas.
Would you see a Qtc of 0.6 as a good starting point for the LT? Your comment makes me feel 0.7 may still be high, and the 12C still has a small box with 0.6. Is 0.6 with LT still a compromise in your view?
Regarding Fp/Qp, are there any things/limits I should be aware of other than Xmax (in my case I am WAY below the drivers Pmax for the needed SPL per driver)?
A Q of 0.6 would be a great target. Lower Q helps when you plan to extend the response using the LT. That is because below Fc the response is not dropping off as fast as when Q is higher, and Fc will be lower. than with higher Q The response will droop a bit more around Fc but since you will be using the LT to EQ to some new response with lower Fc that is not all that important. Test the empty cabinet walls for resonance/ringing before installing the driver. This can be done by tapping or knocking on the sides. You want them to have a "dead" sound. If not you can add some material to help with that. Adding 1/2 inch particle board glued to the inside of the panel using a silicone adhesive that will not harden can help fix this issue, if you need to. You can volume fill the cabinet with stuffing, but I typically don't bother and that can get a bit expensive when you use some of the better performing stuffing material if the cabinet is not small. Anyway, that is the sort of direction I would take the physical enclosure design.
GM, it still is if one looks around. The 12C has lower Mms (136 vs 146 g) , lower BL (13.36 vs 15), lower Re (3.11 vs 4.29) and lower Qms (11.7 vs 13.32). Bl^2/Re is still higher on the "C" (57.39 vs 52.45). Still, I would not know out of this if one would sound better than the other.
As the discussion above using a LT starting from a Qtc=0.6, the internal volume for the "C" would be 54L vs 80 for the non "C".
Here are the sims for both with the LT and showing the point in which I would run our of Xmax. I am using a HP @20hz.
As the discussion above using a LT starting from a Qtc=0.6, the internal volume for the "C" would be 54L vs 80 for the non "C".
Here are the sims for both with the LT and showing the point in which I would run our of Xmax. I am using a HP @20hz.
Attachments
OK then, since my motto is 'BIB (bigger is better) rules' and not being up-to-date WRT driver options, I recommend the LAB12.
I was just going to mention that one. My favorite is SDX10. These go up higher than most subs.
With multiple woofers you should weigh the advantages of multiple woofers or the advantages of a push-push woofer. Both are quite large. 2 push-push would be my choice over 4 separate boxes.
Best of both worls would be 4 push-push woofers and software that figures out how to set them so that they compliment each other.
dave
With multiple woofers you should weigh the advantages of multiple woofers or the advantages of a push-push woofer. Both are quite large. 2 push-push would be my choice over 4 separate boxes.
Best of both worls would be 4 push-push woofers and software that figures out how to set them so that they compliment each other.
dave