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Advice sought: Woofers for compact sealed boxes
Advice sought: Woofers for compact sealed boxes
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Old 29th March 2021, 01:16 AM   #21
Few is offline Few  United States
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Looks like an interesting construction approach! Glad to hear it worked out so well for you. Thanks for sharing it.

Iím aiming for small and inconspicuous, and flat response (as opposed to compensating for lower hearing sensitivity at low frequencies). My excursion-limited calculations suggest Iíll be able to get high enough SPL out of a small box if I donít run out of amplifier power first.
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Old 5th April 2021, 03:25 AM   #22
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I’ve been reading up on push-pull slot-loaded subwoofers. Has anyone seen distortion measurements on the Dayton Reference “high output” drivers? I’m trying to predict whether the push-pull driver arrangement would yield enough advantage to justify the extra enclosure size and complexity. A push-push arrangement would be easier to keep small and also simplify the force-cancelling assembly (just rigidly tie the magnets together). But if push-pull yields an audible improvement I would consider taking on the design challenge.
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Old 5th April 2021, 05:49 PM   #23
norman bates is offline norman bates  United States
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All the shorting rings and stuff don't help below 100hz, compared to push pull.

PiSpeakers Forum - Push-pull versus shorting rings - Wayne Parham, June 21, 2006 at 16:18:33
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Old 5th April 2021, 07:46 PM   #24
Few is offline Few  United States
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Thanks for the link! I'll do my homework--I hadn't seen that information before, and it seems highly relevant.
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Old 5th April 2021, 09:48 PM   #25
norman bates is offline norman bates  United States
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Welcome.
I think the distortion reduction would have been higher if the drivers were closer together.
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Old 6th April 2021, 01:30 AM   #26
Few is offline Few  United States
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Am I misreading the online reports? I’ve seen some showing relatively small distortion reductions from push-pull arrangements, and others showing a larger effect. Clearly it would make sense that drivers with symmetry issues would benefit most, but do the benefits scale simply with the magnitude of the second harmonic distortion? I could argue that such a correlation would make sense, but then things are rarely that simple.
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Old 6th April 2021, 08:55 PM   #27
norman bates is offline norman bates  United States
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Digital Underground - Doowutchyalike (Official Music Video) - YouTube
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Old 8th April 2021, 06:56 AM   #28
bansuri is offline bansuri  Italy
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Quote:
Originally Posted by Few View Post
Am I misreading the online reports? I’ve seen some showing relatively small distortion reductions from push-pull arrangements, and others showing a larger effect. Clearly it would make sense that drivers with symmetry issues would benefit most, but do the benefits scale simply with the magnitude of the second harmonic distortion? I could argue that such a correlation would make sense, but then things are rarely that simple.

Yeah, I think the higher reduction is because they compare it with a single driver.
with balanced drive (wavecor) the speaker has little distortion.
the immense additional space and optics is difficult to justify.
Certainly the box vibration is reduced, a good weight can have the same effect

Last edited by bansuri; 8th April 2021 at 07:01 AM.
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Old 8th April 2021, 02:42 PM   #29
Few is offline Few  United States
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Hi Bansuri,
Which case are you referring to? The audioroundtable.com link provided by Norman Bates indicates it's comparing dual woofers on a baffle to push-pull woofers on a baffle (figure attached). I'm probably misinterpreting your post. Apologies in advance.

In my post I had in mind post #758 on this thread. I've attached screenshots of the push-push and push-pull measurements compared there.

Few
Attached Images
File Type: png Screen Shot 2021-04-08 at 10.36.14 AM.png (181.7 KB, 69 views)
File Type: jpg push-pull 2m dBr.jpg (83.3 KB, 65 views)
File Type: jpg push-push 2m dBr.jpg (82.7 KB, 66 views)
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Old 9th April 2021, 04:19 AM   #30
bansuri is offline bansuri  Italy
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Few. I refer to this white paper



https://www.wavecor.com/Balanced_Dri...ical_paper.pdf


With drivers designed like this there would be no improvement or very little


The posted measurements were of course made with a driver where the effect is extreme. Also it should be noted that the 5th and higher harmonics increased, may be because of the magnet and frame causing reflections.
Or rather the vent acting like a compression driver to the back
That is what the 758 says, I agree 100%

Last edited by bansuri; 9th April 2021 at 04:37 AM.
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