Sonotube Sanity Check - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 9 Old 10-25-2019, 02:42 PM - Thread Starter
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Sonotube Sanity Check

I wanted to run my design through you guys for a sanity check to see if there is anything I could do better or should change

Equipment:
- UM15-22 Subwoofer
- iNuke NU1000DSP amplifier (bridged)
- 24" Sonotube

The amp and sub woofer have been bought. It's as far as I could stretch the budget. UM18-22 would have been nice....maybe in the future sometime. I currently dont have a subwoofer. I have a PSB Image B6 & Image C5 speaker that the subwoofer will be paired with.

Design:
- 400L (14.1 ft^3)
- 17Hz Tune
- 8" port @ 27.2in
- 450w signal





Questions:
- From what I have read, if I turn on the HPF there is a 20Hz shelf with the inuke. Is that something I should model into winISD? The HPF protection makes me feel better with a ported setup
- If I add in a 16Hz HPF in WinISD then it changes the estimated signal power and the port length (540W, 8" @ 25.6in). Am I splitting hairs here?
- I want to install the subwoofer in an upfiring orientation, with the port downfiring. The subwoofer will be in my basement. Would that be too much sound directed at the upper level? Does it make a difference if the sub is up or down firing?
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post #2 of 9 Old 10-25-2019, 02:47 PM
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Quote:
Originally Posted by element_Z View Post
Questions:
- From what I have read, if I turn on the HPF there is a 20Hz shelf with the inuke. Is that something I should model into winISD? The HPF protection makes me feel better with a ported setup
- If I add in a 16Hz HPF in WinISD then it changes the estimated signal power and the port length (540W, 8" @ 25.6in). Am I splitting hairs here?
- I want to install the subwoofer in an upfiring orientation, with the port downfiring. The subwoofer will be in my basement. Would that be too much sound directed at the upper level? Does it make a difference if the sub is up or down firing?
Just model a 2nd order HPF in WinISD at the lowest frequency that keeps excursion in check.
Adding a HPF does not change port length. It seems you may be mistaken or doing something wrong?
It doesn't matter as far as firing at the ceiling or not. At these frequencies they are essentially omnidirectional.

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Video: Sony 85" X900F @ 80" eyes-to-screen (49.4° viewing angle)
Audio: Denon AVR-X4400H 7.2.4 Atmos
Mains: Fusion-15 LR, Fusion-8 Center, Ported Volt-10 Surrounds, Custom 45°/45° Double-Angled Ported Volt-6 Atmos
Subs: The Two Towers (HT18 32cf 11.5Hz x 2), UM18 4cf x 2, Crowson MAs x 4
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post #3 of 9 Old 10-26-2019, 09:16 AM
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Quote:
Originally Posted by element_Z View Post
- 17Hz Tune
- 8" port @ 27.2in
Did you model or consider lowering tune to ~12 hz? Is that viable for your model/tube length?

Quote:
Originally Posted by element_Z View Post
- From what I have read, if I turn on the HPF there is a 20Hz shelf with the inuke. Is that something I should model into winISD? The HPF protection makes me feel better with a ported setup
INUKE should be able to lower the HPF, I used this post from LTD02 for my NX6000D.

Quote:
Originally Posted by element_Z View Post
Does it make a difference if the sub is up or down firing?
I believe that my sonosub is easier to move/transport with driver at the bottom rather than top. Also more stable with a lower CG. Sonosub is lighter than a plywood box sub anyway so movement is going to be relatively easier than a similar sized box.
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post #4 of 9 Old 10-28-2019, 07:18 AM
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The driver is always placed at the bottom of the tube with the port at the top of the tube. I believe he is referring to the orientation of the driver. Most of us face the driver down but of course you can do otherwise....
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post #5 of 9 Old 10-28-2019, 07:24 AM
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Quote:
Originally Posted by buggers View Post
The driver is always placed at the bottom of the tube with the port at the top of the tube. I believe he is referring to the orientation of the driver. Most of us face the driver down but of course you can do otherwise....


It would work fine wither the driver at the top and port at the bottom.
I would be concerned about the raised center of gravity though
Chris


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post #6 of 9 Old 10-28-2019, 09:48 AM - Thread Starter
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Quote:
Originally Posted by Sangui View Post
Did you model or consider lowering tune to ~12 hz? Is that viable for your model/tube length?
I am limited in sonotube size to 16 cu.ft MAX. I did take a look at a lower tune.

- For a 12Hz tune I would be taking a 6dB hit in the 20-30Hz range in order to drop the HPF from 16Hz to 10Hz. I thought this was too much to give up.

- For a 16Hz tune I would be taking a 2.5dB hit in the 20-30Hz range in order to drop the HPF from 16Hz to 14Hz. Is an overall loss in output above 20Hz worth 2Hz lower output?

That's a question I don't know the answer too because I am just bench racing right now by trying to optimize. I don't see myself listening at reference levels. I dont know if I should focus on SPL or range.

Quote:
Originally Posted by buggers View Post
The driver is always placed at the bottom of the tube with the port at the top of the tube. I believe he is referring to the orientation of the driver. Most of us face the driver down but of course you can do otherwise....
Typically yes, the driver is at the bottom of the tube. I wanted to install the subwoofer at the top of the tube. Function wise it wont make a different. I just don't want my kids throwing things down the port.

Is the raised center of gravity an issue while the subwoofer is in use, or a caution in case someone runs into it?


As for progress, I cut out the MDF circles this weekend. Next weekend I am hoping to cut the sonotube down to size and perhaps start making the cuts for the speakers and ports.
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post #7 of 9 Old 10-28-2019, 11:03 AM
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Sonotube Sanity Check

Quote:
Originally Posted by element_Z View Post
I am limited in sonotube size to 16 cu.ft MAX. I did take a look at a lower tune.



- For a 12Hz tune I would be taking a 6dB hit in the 20-30Hz range in order to drop the HPF from 16Hz to 10Hz. I thought this was too much to give up.



- For a 16Hz tune I would be taking a 2.5dB hit in the 20-30Hz range in order to drop the HPF from 16Hz to 14Hz. Is an overall loss in output above 20Hz worth 2Hz lower output?



That's a question I don't know the answer too because I am just bench racing right now by trying to optimize. I don't see myself listening at reference levels. I dont know if I should focus on SPL or range.







Typically yes, the driver is at the bottom of the tube. I wanted to install the subwoofer at the top of the tube. Function wise it wont make a different. I just don't want my kids throwing things down the port.



Is the raised center of gravity an issue while the subwoofer is in use, or a caution in case someone runs into it?





As for progress, I cut out the MDF circles this weekend. Next weekend I am hoping to cut the sonotube down to size and perhaps start making the cuts for the speakers and ports.


Depending on the weight of the woofer, it could be quite tippy. I’d be concerned about kid knocking/pulling it over.

Just put a speaker grill over the port. Plus, at 16cf, I’m assuming a 6’ tall tube, finished height closer to 7ft. Thats a pretty impressive throw.

Chris

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post #8 of 9 Old 10-29-2019, 09:06 AM
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[QUOTE=element_Z;58741874I just don't want my kids throwing things down the port.

Is the raised center of gravity an issue while the subwoofer is in use, or a caution in case someone runs into it?
[/QUOTE]

You can put a screen or some other material over it. And yes the raised center of gravity would for sure be a falling hazard. Especially around kids.
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post #9 of 9 Old 10-29-2019, 01:21 PM
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Quote:
Originally Posted by element_Z View Post
...I just don't want my kids throwing things down the port...
NO THROWING THINGS IN THE HOUSE

There. Problem solved.

"The wise understand by themselves; fools follow the reports of others"-Tibetan Proverb
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