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Multiple Small Subs - Geddes Approach
Multiple Small Subs - Geddes Approach
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Old 19th February 2019, 05:44 PM   #1851
badman is offline badman  United States
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Quote:
Originally Posted by Ibanezrg7620 View Post
Greetings,
thank you for your reply. I really apprecite it. So its woth a try...

Anyway is Mr. Geddes still around? GedLee official website says hes retired.

Feel free and keep me in loop with your own multisub project. Thanks in advance
He's been retired for some years but still participates. Certainly multisub is the best solution for real-world spaces IMO, I've tried a few different configurations over the years and my rig is generally appreciated by listeners for the bass and sense of spaciousness, which is highly correlated to good bass. Frequency extremes tend to help each other, there's an old rule of thumb that if your highs are rolled off your lows should be too, and vice versa, if you're going to have high top-end bandwidth/power response, you need a good sub(s) to balance it.
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Old 18th March 2019, 03:14 AM   #1852
dogshome is offline dogshome  United Kingdom
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I recently placed a second sub in my living room. This was for no other reason than I bought two empty Lima enclosures at a very low price and had a pair of jbl gto804 drivers.

The drivers are less efficient than the single 12" 96L unit I was using, so some adjustment to the gain was needed. The headroom is probably less, but the effect of two subs is very good.

The quiet spot at one end of the couch has gone and the low end is now noticeable in that it does not wipe out in certain spots or frequencies. Film effects still go boom! But bass in music doesn't now Then I spotted this thread.........
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Old 18th March 2019, 07:25 AM   #1853
AllenB is offline AllenB  Australia
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Welcome to the machine.
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Old 19th March 2019, 06:05 PM   #1854
Ibanezrg7620 is offline Ibanezrg7620
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Hello guys.
As I mentioned above, Im bulding DIY mixing studio (control room) and would like to use multisub solution to tame room modes.
I have one question. Is possible to close the port of the originally ported subs to achieve faster sub response? Im planning to buy few Presonus T10 active subs. Could sealing the ports make any damage to the drivers?

Thanks.
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Old 28th March 2019, 09:10 PM   #1855
dogshome is offline dogshome  United Kingdom
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Quote:
Originally Posted by Ibanezrg7620 View Post
Hello guys.
As I mentioned above, Im bulding DIY mixing studio (control room) and would like to use multisub solution to tame room modes.
I have one question. Is possible to close the port of the originally ported subs to achieve faster sub response? Im planning to buy few Presonus T10 active subs. Could sealing the ports make any damage to the drivers?

Thanks.
You may get a few replies to this! Generally, for the same driver a vented enclosure will be larger than that required for a sealed enclosure. My experience with an 8" driver in a sealed box designed for a 10" resulted in the coil smacking the metalwork. I thought someone had thrown a tennis ball at the car. Nope.

Are the T10s designed to be switchable vented/sealed? If not I would advise against it.

PS there are some really mixed reviews on that sub. Try before buy?

Last edited by dogshome; 28th March 2019 at 09:16 PM.
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Old 29th March 2019, 03:02 AM   #1856
gedlee is offline gedlee  United States
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To me, the enclosure design for a subwoofer is irrelevant. That's because if you are doing multiple subs then you really need to have individual control of each sub. So I would just seal off the port. I've done this dozens of times, to the point that I only build closed box and never even consider the box size. With DSP control none of that tuning stuff matters.
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Old 29th March 2019, 06:25 AM   #1857
wonderfulaudio is offline wonderfulaudio
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Quote:
Originally Posted by gedlee View Post
To me, the enclosure design for a subwoofer is irrelevant. That's because if you are doing multiple subs then you really need to have individual control of each sub. So I would just seal off the port. I've done this dozens of times, to the point that I only build closed box and never even consider the box size. With DSP control none of that tuning stuff matters.
Hi Earl,

Since a low ported enclosure gives the bottom octave almost free, so a 10" sealed could be replaced by 8" ported. Boxes could get smaller especially for rooms that have no modes near the box tuning frequency. So all subs are in phase there and thus share the SPL. If any sub needs flipping the phase (as needed by multi sub procedure ) then that sub can be made sealed by stuffing the port, is my understanding correct? The others can still remain ported and benefit in the lowest octave.

Thanks,
WA
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Old 29th March 2019, 07:05 AM   #1858
Ibanezrg7620 is offline Ibanezrg7620
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Quote:
Originally Posted by dogshome View Post
You may get a few replies to this! Generally, for the same driver a vented enclosure will be larger than that required for a sealed enclosure. My experience with an 8" driver in a sealed box designed for a 10" resulted in the coil smacking the metalwork. I thought someone had thrown a tennis ball at the car. Nope.

Are the T10s designed to be switchable vented/sealed? If not I would advise against it.

PS there are some really mixed reviews on that sub. Try before buy?
Hello. Thank you for your reply.
Originally Presonus T10 is ported design, its not mentioned in the user manual to be switchable vented/sealed. Im sure Audiokinesiss systems The Swarm and Debra are switchable, Ive talked to Mr. Duke and his colleague from Europe.
Ive read a lot of positive user reviews for those subs considering what they offer in that price range. Im not sure I there will be any possibility to try before buy (Prices in Slovenia are high and they usually dont have a stock of multiple pieces, so buying from abroad is my only option), I guess Ill be forced to sell the if they will not show results I would like to achieve.
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Old 29th March 2019, 07:13 AM   #1859
Ibanezrg7620 is offline Ibanezrg7620
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Quote:
Originally Posted by gedlee View Post
To me, the enclosure design for a subwoofer is irrelevant. That's because if you are doing multiple subs then you really need to have individual control of each sub. So I would just seal off the port. I've done this dozens of times, to the point that I only build closed box and never even consider the box size. With DSP control none of that tuning stuff matters.
Hello Dr. Geddes,
thank you for your response. Ive wrote you a message on Facebook about a month or two ago but I guess youre not using it so often anymore.
Im planning to control the subs with DBX DriveRack 260, allowing me full control over each and every sub/main speakers. Do you find MSO app (made by Andy C) useful for finding the right settings for the DSP?
Thanks a lot!
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Old 29th March 2019, 07:17 AM   #1860
nugat is offline nugat  Europe
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I also, like Gedlee, never put vents on my dsp-ed subs. The sealed ones have a tighter bass. Ports give this flabby bottom and you cannot dsp it away. Easy to test when closing the port with a plumbing plug ( the type where the hard plastic thread screws into the rubber seal).

Last edited by nugat; 29th March 2019 at 07:24 AM.
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