So allen
Reason is I don't think 15 will be fast enough to keep up with higher frequencies. Plus it's an older driver velodyne fsr15+ Dayton audio 500 watt dsp sub amp.
Was thinking of getting rid of this one and have a 2 x 12" subs..what will a 15" sub do that 2 12s won't? Again many variables. But let's say both 15 and 12s are built with identical quality and both operate in the perfect sealed volume for them
So allen. How do you use them properly. I have a velodyne 15" subwoofer..I set the cross over all the way down 35hz and sharpest slope down( 24 I believe as opposed to 12).
Reason is I don't think 15 will be fast enough to keep up with higher frequencies. Plus it's an older driver velodyne fsr15+ Dayton audio 500 watt dsp sub amp.
Was thinking of getting rid of this one and have a 2 x 12" subs..what will a 15" sub do that 2 12s won't? Again many variables. But let's say both 15 and 12s are built with identical quality and both operate in the perfect sealed volume for them
One of the things that Brett mentioned was bandwidth. I've used 15" drivers up to the 1kHz region, give or take a couple of hundred. No problem when you choose the right 15" driver.
In this region the dominant factors are likely to be the room, and the group delay. It would be easy but incorrect to blame the 15" driver for these.
Having two subs allows greater positional versatility with regards to treating room modes. The size in this case doesn't mean very much in my opinion.
for reasons i wont disclose, ill actually put this directly to the test. the idea that 15" are slower then 12" are a myth.
Im building a smaller speaker using 2x12" . I will compare to my 15" and report back.
15" woofer is the eminence pro 15a and the 12" Beyma 12br70. mid and treble and xo will stay exactly the same.
Im pretty sure the pro 15 a will be faster, since the specs seem to indicate it will
If you're going from 15 WMT to 12 WWMT then the xover frequency, type and slope as well as driver positioning will also have a likely audible effect.
Bandwidth determines speed and a 12 and 15 that have the same bandwidth will be as 'fast' as each other.
Apart from being able to place them in different locations to possibly ameliorate room modes, what do 2x12 offer than 1x15 doesn't when used as a low bandwidth subwoofer and they have the same volume displacement?
Note that this thread was not started talking about subs, but midbass drivers.
yeah, going from 15 WMT to 12 WWMT would not be a identical comparison indeed since my XO is way too high around 300hz! I was thinking having the two 12's adjacent to each other, like this https://www.genelec.com/1238df
Genelec are clever here, since this arrangement might be problematic without the waveguided mid
Much better I think, especially with the xover lowish.
The WG isn't all that large so I don't think it's going to have much effect that low, but I'm eyeballing only.
Hmm. That configuration of woofers tends to behave the opposite of the waveguide (assuming we could determine it by simply looking 😉 ). Going below it all would make things moot... the only benefit of the smaller drivers being a cabinet that's shorter. Besides, that waveguide isn't designed to handle lower frequencies. It's rather asymmetrical.
Ok, thx guys, i would have thought the mid WG would have helped.
going with this arrangement, should i offset the mid and tweeter or should it be centered? I hope my question is clear.
for my design, going dual 12’s vs the 15’s will make possible to lower the cab size by half. Hopefully going from 150l cab with the 15’s to 75l cab with dual 12’s
That's your choice. Offsetting is sometimes done where a design has diffraction, in order to splash the diffraction around hoping to get a flatter result on one axis. You could always try to deal with that diffraction instead, because you're already dealing with curves because of the waveguide.
A little on asymmetric waveguides designed for baffle mounting.
https://www.diyaudio.com/community/threads/is-it-best-to-use-a-non-axisymmetric-waveguide.375799/
What do people mean by "fast"? In my head you only need "fast" if you're making high frequencies. For a woofer you'll be low passing it before this ever becomes an issue - and if you are wanting HF then beaming due to the width of the source, or cone breakup modes would surely become a problem before this?
Maybe when people say "fast" they're hearing some other thing, maybe an undersized motor, or more group delay or something?
Or maybe they're talking literally - to produce the same SPL the 12" has to move further within the same time period? I'd argue this isn't necessarily a good thing.
Maybe when people say "fast" they're hearing some other thing, maybe an undersized motor, or more group delay or something?
Or maybe they're talking literally - to produce the same SPL the 12" has to move further within the same time period? I'd argue this isn't necessarily a good thing.
Some good points.
When the motor is less powerful then the sensitivity tends do drop. The higher frequencies are still there with the lower ones. Even at much higher frequencies beyond the start of breakup, where the woofer is rolling off, you can get a flat response by equalising.. demonstrating that increasing the drive signal was all it took to fix.
That's not going to be one of them. The fact that there is a measured response at higher frequencies means that reproducing it was successful, all the speed needed was available so to speak.
When the motor is less powerful then the sensitivity tends do drop. The higher frequencies are still there with the lower ones. Even at much higher frequencies beyond the start of breakup, where the woofer is rolling off, you can get a flat response by equalising.. demonstrating that increasing the drive signal was all it took to fix.
IMHO (apparently not shared by many on diyaudio) different speaker cones, surrounds, coils, motors, etc., have audible and measurable differences (i.e. distortion) in impulse response curves beyond frequency response (FR) and bandwidth (BW). When BW is extended with higher-frequency drivers, the XOs can introduce additional complex group delays and distortion to damage further the combined impulse response, so the curve looks both qualitatively and quantitatively worse despite greater system BW and flatter FR. Hence slow/smeared/undynamic bass.
Proved mathematically to my own satisfaction https://www.diyaudio.com/community/...go-for-3-way-then.391639/page-10#post-7167908
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What you've said here makes sense. I'm not sure why people wouldn't accept that it happens.. although everything needs also to be qualified by how audible it is.
Yeah, we gotta remember any problem free system impulse/step response can be straightened with FIR filter. By problem free I mean when the drivers are good, when the construct is good and there is no bad resonances and edge diffraction, in other words secondary sound sources, then all we have to do is as good filter as we can and this is trivial with VituixCAD and DSP system.
Basically, if one wants to make "perfect" system start figuring out what kind of construct that is, that measures so that it sounds great in room to you? Its acoustic problem, electronics part I consider trivial. Using ideal drivers and assuming there is no limit in budget, there can be DSP, size and looks can be anything. Impulse response is not a problem if you allow these design parameters, like use of FIR capable DSP. Now, what kind of system one arrives to?🙂
Basically, if one wants to make "perfect" system start figuring out what kind of construct that is, that measures so that it sounds great in room to you? Its acoustic problem, electronics part I consider trivial. Using ideal drivers and assuming there is no limit in budget, there can be DSP, size and looks can be anything. Impulse response is not a problem if you allow these design parameters, like use of FIR capable DSP. Now, what kind of system one arrives to?🙂
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Option to use FIR is a design freedom. Basically, while designing a loudspeaker system and thinking compromises one could sacrifice impulse response for some other important thing if needed, and then have it back by including FIR.
edit. a post disappeared which this was response to so edited little.
edit. a post disappeared which this was response to so edited little.
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I don’t know if the 15pr400 is good enough, but it has gone up 40% in price in 2022! At one point it was even cheaper at 170 euro or so, now it’s more like 260-280
I bought the 15pr400 late last year on partsexpress and they were ~270 now they are ~350 usd.
Anyways, I just bought a pair of new old stock TAD 1601a that were on sale here last week. I will get them installed this weekend. Look forward to see what they sound like. If weight correlates to sound quality, they should be 3-4 times better than the failtal and 2x better than Altecs. They have the biggest magnet I have ever seen.
I've owned a lot of woofers, but the Tad 1601's were the best...
