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I am planning to build my first dipole speakers and would like to know what effect this has (if any) on baffle step compensation. If there is still a need and it differs from that of a monopole, is there some formula to predict? Thank you in advance for any guidance.
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You don't necessarily have baffle step in an open baffle. What you do have is a 6db per octave drop in low end response depending on the size of your baffle. The bigger the baffle, the lower this frequency will be. You will also have a dipole peak at the frequency where the rear waves sum to the front waves, and this is also dependent on the baffle size. There are many online calculators that can help you with this. -
Technically you still have a baffle impact but the dipole peak and roll off continues past the step. You can see this with "Edge" program. There is still a need to flatten the driver frequency response to improve the sound.
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Not sure if this matters but I'm not planning an open baffle, just separate identical drivers front and rear in a common enclosure.Comment
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In phase. I would think out of phase drivers in a common enclosure would cancel the effect of the enclosure rendering it pointless.Comment
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In phase means you have a monopole, The rear woofer out of phase with a front woofer is a dipole. Some time you see in phase woofers with one of the baskets reversed (pointing out/ exposed) for subjective distortion improvements.Comment
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I apologize for my mistaken understanding of the terminology. I believe what I am intending is referred to as bipole. Speakers on opposite sides of the same enclosure (front and back in this case) in phase and facing out of the enclosure. In this instance, is baffle step compensation needed? If so, is it the same as, greater to or less than a single front facing driver?Comment
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BSC is used to account for the shift from half space to full space loading that occurs where the baffle is less than a wavelength in dimension, so it would be used in this case. Since it's determined by the baffle dimension the number and orientation of drivers doesn't matter. This configuration will result in a cancellation notch where the front and rear radiations meet at 180 degrees, so it's not without its issues.
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That's a good question wrt is baffle step compensation more or less with a second woofer mount in the back. The answer is to measure, but assuming the listening axis is to the front driver with a typical baffle peak the rear speakers response will wrap and notch where the response is out of phase. That notch location could reduce the magnitude of the baffle peak.
We don't know what your building if this is a subwoofer or 3-way woofer, much of this discussion is N/A.Comment
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Planned project is as follows and based on drivers I have on hand with no home. 5"Wx9"Dx48"H with a Tang Band W-740C mounted on the side and 4 HiVi B3S's mounted either 2 front and 2 rear or 4 on the front tightly spaced in either case, wired series / parallel and all in phase. I intend to use the circuit found on the ZaphAudio.com site to tame the response and possibly the BSC as well. Crossover between them and the Tang band sub to be somewhere between 200 and 500Hz. I just downloaded Jeff Bagby's crossover design software 3 days ago and am stumbling through figuring out how to design something that sounds decent. Enclosure will net 2 subenclosures that are .4 cu ft each. Tuning the bass enclosure to 33hz gives a reasonably flat response and an f3 of 37hz, acceptable group delay and no excursion problems according to WinISD. The biggest issue with the 3" HiVi drivers appears to be efficiency, which is why I'd like to use 4 of them. Any thoughts, advise or comments would be much appreciated. I've built many speakers designed by others but have no design experience of my own beyond subwoofers.Comment
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Put the HiVi on the front vertically arrayed. Two on the front and two on the back isn't going to do anything to improve sensitivity where you want it, in the listening area.Comment
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Well it sounds like 4 B3S's on the front for sensitivity and a 200hz crossover is the way to go. I'd prefer not to cross lower for power handling of the HiVi's. Bi Amp and active crossover will be an option for a later date.Comment
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You can go as high as 250Hz with the side firing woofer without directionality being a problem when they're in the same box. Even 300Hz may be OK, I just have personal experience going to 250Hz.Comment
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(I know you're not a fan of PMs - but I'd appreciate some of your knowledge)
Hey Bill (hope you're having a good winter up there in NH - my wife lived there once),
Being an enthusiastic proponent of WinISD (I typically use 0.50a7 myself), I was wondering if you knew where ISD stores drivers - once its "Drivers" folder fills up.
I still add drivers (nearly every day), and I've got about 500 that I added (that are in the Driver folder), but there are no NEW entries in there since 2014. I just added one today, and it stored it (and I can recall it), but I have no idea where the data is being kept. I'm pretty good w/'puters (and used to program quite a bit), and have looked into this years before - but I can not figure it out.
If I wanted to move on from my 15 y.o. Vista machine, I'd like to know that I wouldn't have lost the last 1000 drivers that I entered into the DB.
Thanks
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