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Single FR on huge OB?
Single FR on huge OB?
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Old 26th June 2020, 09:20 AM   #11
laserscrape is offline laserscrape
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So i made quick and dirty baffle from some pine planks for just one of the drivers, a couple of 400x1200mm planks side by side for 800x1200mm baffle.
It has *some* bass, not non-existent bass like the other smaller baffle but not enough either, however much more importantly it sounded absolutely awful on this baffle... so that settles that.
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Old 27th June 2020, 12:42 AM   #12
Richard Ellis is offline Richard Ellis  Argentina
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I think I found just why your down on bass response...I see thirty, ( 30 ) decibels down from 100 hertz, to twenty hertz.

=========================================Rick..... ..
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Old 27th June 2020, 01:28 AM   #13
OllBoll is offline OllBoll  Sweden
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There is a good reason almost none is building single driver OB speakers. Most are using some kind of woofer support like the slot-loaded-open-baffle.

If I plug the math into calculations I got from Linkwitz Rileys dipole max-spl spreadsheet we have 20cm3 displacement for the alpair 7p. Even with a 800 mm wide baffle with a fequal of 120 hz (dipole spl = monopole spl) the max spl at 100 hz is 91 dB @ driver xmax.

Thats not a lot, and that is with excessive 800 mm wide baffles.

The driver would perform a lot better if you highcrossed it at 200 hz or higher given a ~ 300 mm wide baffle and used woofers to cover below. Probably closer to 250-300 hz if you want to use a smaller baffle.

Last edited by OllBoll; 27th June 2020 at 01:32 AM.
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Old 27th June 2020, 02:11 AM   #14
planet10 is offline planet10  Canada
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Single FR on huge OB?
If you put the A7p in an infinite baffle it will have a system Q = Qts = 0.5. This is a bit lower than most prefer. A little EQ will help but it is a 4” driver with limited excursion so quantity will be limited.

There are few drivers that will produce decent bass in a (large) OB without EQ. In my experience the VIsaton B200, an Omnes 8” and a Korean-made 6.5” that was specifically made for OB. At one diyFEST we constructed a 16’ wide OB and the bass was staggering… probably a bit over the top.

Single FR on huge OB?-diyfest-16foot-ob-jpg

dave
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Old 27th June 2020, 02:23 AM   #15
norman bates is offline norman bates  United States
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My 12” on a phy open baffle had 2’ deep wings.
Dip at 280hz, peak at 140, then falling off fast below that.
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Old 27th June 2020, 03:15 AM   #16
mp9 is offline mp9  United States
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Single FR on huge OB?
^ Are PHY drivers back in production?
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Old 27th June 2020, 04:10 AM   #17
norman bates is offline norman bates  United States
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Idk, I used a philips driver.
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