I'm trying to decide between the Dayton RS315HF and the AE IB12 (or I guess OB12) for my dipoles.
Crossover is 100-120 at the top. Usually I use a sealed sub at 40Hz, but I'd like the option to go all the way down, albeit at lower volume.
Any thoughts?
Crossover is 100-120 at the top. Usually I use a sealed sub at 40Hz, but I'd like the option to go all the way down, albeit at lower volume.
Any thoughts?
Below 40Hz, stick with a proper monopole sub. The AE speakers unit is probably (vastly) superior. I haven't heard either though.
Another option is a JBL 123A-3 or 2213. Might take some doing, but they're superb drivers well-suited to OB, due to their heavy, relatively high Qts (.5) low Fs (25Hz) nature.
But make sure you have a way to test them. They're very common and can be had for $150 the pair with some looking, but can have demagnetized motors due to overdriving.
GREAT drivers though.
Another option is a JBL 123A-3 or 2213. Might take some doing, but they're superb drivers well-suited to OB, due to their heavy, relatively high Qts (.5) low Fs (25Hz) nature.
But make sure you have a way to test them. They're very common and can be had for $150 the pair with some looking, but can have demagnetized motors due to overdriving.
GREAT drivers though.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=290-330
I'd choose these for open baffle bass.
I'd choose these for open baffle bass.
Related to the above drivers, a build using GW 10"" http://www.diyaudio.com/forums/showthread.php?t=152310. Very different drivers from what the OP is looking at, but worth considering. Lets do a little work-up:
First, you could get more specific about what your concerns are, particularly as the AE drivers are quite a bit of money. Also, your planned enclosure.
The main thing the AE drivers have going for them is low non-linear distortion at high volumes. There is a decent argument that non-linear distortion is not a major factor in sound quality (particularly at 'home' listening levels) - ie,psychoacoustic masking of higher tones, and the harmonic structure of real instruments. The AE driver is a very well built driver, and has somewhat higher sensitivity (possibly 4dB, but it depends on the enclosure).
There are a couple of things to note here though - .68 Qts is high for a subwoofer, but OB people often look higher. It generally takes a value of around 1 to keep things flat down low. But this brings us to the enclosure/baffle - which has a major impact on the speakers response. Generally, a driver that is rated 'high sensitivity' will still fall dramatically when used OB. If you want to have a closer idea of what a driver with enclosure will be doing in room, you need to sim it with MJK's mathcad worksheets. This is the most reliable way to know before hand with OB. Does using active EQ matter to you? You will need it with these drivers.
Ultimately, I would not choose the AE driver. I currently haven't found non-linear distortion to be a significant enough issue to warrant lots of money. The Dayton driver is also a well designed driver, and the RS line has low non-linear distortion relative to most other drivers. The two drivers also have the same volume displacement (so have the same maximum output, theoretically), and almost the same Qts value. The RS driver is half the cost.
The link above is for a complete bass driver/enclosure design that I put together with some fairly specific design goals. The bandpass is 50Hz to 200Hz. It plays loud, needs little to no EQ on the low end, and has decent sensitivity (particularly as a completed design). It costs relatively less than other high output designs, and the use of multiple drivers brings up the sensitivity while lowering non-linear distortion. Also, it has a relatively small footprint for OB woofers.
I agree with Badman, below 40Hz is monopole sub territory. Hence the band pass of 50Hz for my design - there is no point in paying for something you're not going to use.
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All drivers that I've tried in OB, have very audible mechanical noise at full excursion. So high xmax is useless. When I look for OB woofer I look for high qts numbers, everything else is not important.
and I agree with cuibono, .68 Qts is high, but not high enough for use in OB.
and I agree with cuibono, .68 Qts is high, but not high enough for use in OB.
If very high SPL or the sense of strong vibration (instead of 'sound') is not needed, then I'd suggest another monopole sub maybe skipped. (especially if you are going to build up a new system from scratch)
Around 30Hz is doable by OB bass, and with reasonable SPL for household use. Given that the major powerful bass notes in music are mostly in the 40~80Hz range, LF down to 30-some is actually coming with some portion of "sense of vibration" already (more than enough to scare those mini-monitor users). Rumbls and roars by pipe organ can be played cleanly and clearly with pretty strong energy by OB bass (you'll love it for sure).
If there're surplus woofers and plate amps lying around, then of course you may build any 'additional' monsters as you like. They will give you some more rattles on windows/furnitures/ceiling... etc.
Around 30Hz is doable by OB bass, and with reasonable SPL for household use. Given that the major powerful bass notes in music are mostly in the 40~80Hz range, LF down to 30-some is actually coming with some portion of "sense of vibration" already (more than enough to scare those mini-monitor users). Rumbls and roars by pipe organ can be played cleanly and clearly with pretty strong energy by OB bass (you'll love it for sure).
If there're surplus woofers and plate amps lying around, then of course you may build any 'additional' monsters as you like. They will give you some more rattles on windows/furnitures/ceiling... etc.
Sorry, I should have been specific. I'm replacing the existing Adire DPL12 drivers in my Orion-style dipoles. There will be two a side in an H-frame. The DPL12s are a very good purpose-built dipole driver, but are at their best below 40Hz distortion-wise.
The Dayton RS315HF and the AE IB12 are the same price.
The Dayton RS315HF and the AE IB12 are the same price.
Hmm, my bad about the price, I was looking at the OB12. I would go with the AE then - although the only significant differences I see are higher build quality, a bit more sensitive, and probably lower distortion.
I couldn't find any specs for the Adire driver, so I'm not sure what you're trying to improve on? Max output? Smoother FR? Higher sensitivity?
Particularly if you're using a sub, and limiting the woofers bandwidth to 45-120Hz, I wonder what improvements would justify the cost?
I couldn't find any specs for the Adire driver, so I'm not sure what you're trying to improve on? Max output? Smoother FR? Higher sensitivity?
Particularly if you're using a sub, and limiting the woofers bandwidth to 45-120Hz, I wonder what improvements would justify the cost?
The AE, if for no other reason than the excellent motor and stonkingly good build quality.
Expect postage to be high.
There's probably not a major difference, but I'm redoing my sealed sub and the DPL12 works very well in that enclosure so I'm transferring them into that.
Also, I just feel like buying something new.
🙂
Might I ask - why is it that high Qts is sought after for OB drivers? I would have thought you'd want a low Qts to keep the cone under control, as there is no enclosure derrived damping.
Jim
The high Qts buys you a couple extra dB on the low end. Most users go to .8-1 range to compensate for baffle rolloff.
No, that depends on the design of the drive unit itself.
As frequency decreases the higher Q loudspeaker will have a shallower roll off compared to a low Q loudspeaker, providing we're above resonance.
To keep the SPL constant as frequency decreases, the higher Q loudspeaker will require less EQ and as a result will also require less power to achieve this.
The Orion uses two Peerless XLS drivers, these have a really low Q of 0.17 or so. Linkwitz uses his transform circuit to bring the Q of the driver back up to 0.5. After which he uses a standard shelving circuit to compensate for the open baffle losses.
One thing of note with the XLS series is their lack of noise at high excursions. They have very well ventilated motors and cones keeping chuffing to a minimum.
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Martin King has an open baffel design that is verry informative ( www.quarter-wave.com)
Where he compaires the preformance of 3 different woffers with QTS values of .3 , .58 and 1.26 on a baffle 20" x 38" , it's a good read.
Where he compaires the preformance of 3 different woffers with QTS values of .3 , .58 and 1.26 on a baffle 20" x 38" , it's a good read.
The Dayton RS Steve mentioned has been tested and found to be quiet on an OB as well as very low distortion. The Peerless SL uses is also quiet. I don't know if anyone has checked the AE for backside mechanical noise or not. Steve is using a digital EQ/crossover box in "Bob" so he can dial in any driver and Q is pretty irrelevant. Distortion and chuffing are the big things.
it's easy to equalize low q driver, but it would put huge load on amplifier.
and you'd have to pay for equalizer, monster amp and expensive low Q woofer, just to achieve performance of a cheap high Q driver.
and if you listen to music all day long, I think there will be quite a difference in electric bill 🙂 MJK's approach to OB is most efficient one.
and you'd have to pay for equalizer, monster amp and expensive low Q woofer, just to achieve performance of a cheap high Q driver.
and if you listen to music all day long, I think there will be quite a difference in electric bill 🙂 MJK's approach to OB is most efficient one.
That's not really true. Most times, the reason a driver has low Q is because it has a strong motor. That makes it more efficient, not less efficient. In the case of the Peerless SL uses, and other similar subwoofer drivers, the efficiency is reduced by the heavy moving mass which is how they get Fs down around 20 Hz. But you can still drive it to near the Xmax at 20 Hz with a 60 watt amp so I don't see it as being prohibitive.
As Dennis said, you don't need much power. I run a pair of 12"s a side with under 100 watts. The system is excursion limited, not power limited.
I had high-Q drivers (Eminence Alpha 15s) before. They sound great but very limited in XMAX - 3mm. As my system is active, I really don't care whether the Q is high of low. If the Q is high, I use Linkwitz Transform, if the Q is low I just equalise the two poles.
The interesting thing is my cheap jaycar 10" (Qt 0.75, fs 28hz) sounds subjectively lower compared to the 15". I'm quite sure xmax play a part but not 100% sure.
If I ever need dipole woofers it would be a low-Q 12". They're easier to EQ and have sufficiently low Fs.
The interesting thing is my cheap jaycar 10" (Qt 0.75, fs 28hz) sounds subjectively lower compared to the 15". I'm quite sure xmax play a part but not 100% sure.
If I ever need dipole woofers it would be a low-Q 12". They're easier to EQ and have sufficiently low Fs.
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