Ported full range Mains with Ported subs - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 39 Old 11-01-2019, 05:08 PM - Thread Starter
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Ported full range Mains with Ported subs

I am building some two channel music setup. We want to run full range mains ports tuned to around 40hz-32hz with some ported subs tuned to 20hz-27hz ish will this be a problem. There will be hi pass filter on mains at tune same with subs.
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post #2 of 39 Old 11-02-2019, 08:35 AM
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That's a decent spread in tuning, both from subs to mains as well as the spread you've given for each (20-37, 32-40).

Mains should be highpassed at or just below tuning to protect the drivers regardless of sub used. HP at 20Hz with a 40Hz tune would be a problem.

You can integrate the two as you describe them with proper measurement, eq (like a minidsp), time and patience. Would probably be easier if the mains were sealed, started rolling off 12 dB/oct at 50-60Hz or whatever, and a 12dB/oct lowpass on the sub was set to match.
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post #3 of 39 Old 11-02-2019, 09:36 AM
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What music are you planning to listen to. Have you listened to a system with a sub crossed over at 40hz vs say 70hz or 80hz. Even with high end speakers that can hit hard at bass frequencies and comparable subwoofer will hit those notes much better. Both in accuracy and spl. I tested my mains a couple times being used as “subs” (they are ported around 30-35hz). Crossed them at 40hz (lowest the setting in my avr go before full range) and sounded like I lost 70% of the bass. Now I leave them crossed at 80hz but your tastes may differ.
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post #4 of 39 Old 11-04-2019, 08:14 PM - Thread Starter
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Originally Posted by [email protected] View Post
What music are you planning to listen to. Have you listened to a system with a sub crossed over at 40hz vs say 70hz or 80hz. Even with high end speakers that can hit hard at bass frequencies and comparable subwoofer will hit those notes much better. Both in accuracy and spl. I tested my mains a couple times being used as “subs” (they are ported around 30-35hz). Crossed them at 40hz (lowest the setting in my avr go before full range) and sounded like I lost 70% of the bass. Now I leave them crossed at 80hz but your tastes may differ.

If you lost 70% of your bass by adding more bass to your mains something wrong with your system!!!
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post #5 of 39 Old 11-04-2019, 08:16 PM - Thread Starter
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Originally Posted by Bigus View Post
Mains should be highpassed at or just below tuning to protect the drivers regardless of sub used. HP at 20Hz with a 40Hz tune would be a problem.

I said thats what I would do with hp filter.
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post #6 of 39 Old 11-04-2019, 08:21 PM
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Originally Posted by rotgg View Post
If you lost 70% of your bass by adding more bass to your mains something wrong with your system!!!
This would possibly indicate phase issues between speakers, or sometimes this can occur based on the room interaction with the crossover frequency causing weird cancellations.
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post #7 of 39 Old 11-05-2019, 10:35 AM
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Originally Posted by rotgg View Post
I said thats what I would do with hp filter.
Sorry, misread. I thought you meant there would be a HP filter the same as the subs tune.

What you are proposing can be done but it can be an integration headache and no guarantee the result is close to optimal.
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post #8 of 39 Old 11-05-2019, 12:41 PM
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Quote:
Originally Posted by Bigus View Post
Mains should be highpassed at or just below tuning to protect the drivers regardless of sub used.

An alternative is to HP the mains a bit above tuning.

There's still a sizeable contribution to output from the port, and associated increase in power handling and lower distortion from reduced cone excursion.

By the time you account for the phase shift contributed by the XO, the overall phase may not be that different than if the mains were sealed, likely making integration easier.

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post #9 of 39 Old 11-05-2019, 12:50 PM
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Originally Posted by rotgg View Post
If you lost 70% of your bass by adding more bass to your mains something wrong with your system!!!
He added more bass to his mains... and removed (at least some) of the bass from his subs. There isn't anything obviously wrong with his system, it's just that his subs do better with the diverted 40-70Hz frequencies than his mains do. When considering room placement and the physics of those longer waves, it makes sense to me.

Just because your mains can go lower, doesn't necessarily mean they should. Sub placement is always a hot topic for a reason.
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post #10 of 39 Old 11-05-2019, 12:57 PM
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Quote:
Originally Posted by rotgg View Post
I am building some two channel music setup. We want to run full range mains ports tuned to around 40hz-32hz with some ported subs tuned to 20hz-27hz ish will this be a problem. There will be hi pass filter on mains at tune same with subs.
Any reason that you are set on such a low 40Hz cross on the mains? Localization of sounds generally a good bit higher than that - closer to 70-90Hz, if I recall correctly. I'd look to a more conventional set of mains and cross them over around 60-80Hz down to properly located subwoofer(s).

Take your choice on subwoofer tuning. I'd consider whether you ever plan to convert the sub over to home theater duties, and if so, you may want a lower tuning frequency.

If you want to get real serious about the setup, check out minidsp options and start reading up on REW. It may take some wrestling, but you should be able to integrate your suggestions above.

I wouldn't say you'll necessarily hit a problem with your idea, but I do think there are more efficient and better sounding ways to approach a two channel setup than that approach.
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post #11 of 39 Old 11-05-2019, 12:59 PM
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Quote:
Originally Posted by noah katz View Post
An alternative is to HP the mains a bit above tuning.

There's still a sizeable contribution to output from the port, and associated increase in power handling and lower distortion from reduced cone excursion.

By the time you account for the phase shift contributed by the XO, the overall phase may not be that different than if the mains were sealed, likely making integration easier.
Good point. If high enough can probably use common 24dB LR and not see much difference near port tuning. Sort of wasting the extra ensure size needed for the port, but it would probably make integration easier.
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post #12 of 39 Old 11-05-2019, 01:47 PM
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Originally Posted by Heide264 View Post
Any reason that you are set on such a low 40Hz cross on the mains? Localization of sounds generally a good bit higher than that - closer to 70-90Hz, if I recall correctly. I'd look to a more conventional set of mains and cross them over around 60-80Hz down to properly located subwoofer(s).

Another benefit to higher XO is increasing the freq range of the mode-canceling/smoothing effects of multiple subs.

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post #13 of 39 Old 11-05-2019, 11:00 PM - Thread Starter
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The mains will be two bms 18n860 per side with compression driver B&C DCX464. The 18's will be ported at 32hz subs will be either devastator's, MBM 21's or skrams X 4





https://www.bcspeakers.com/en/produc...1-4/8/DCX464-8

http://www.bmsspeakers.com/Overview.1251.0.html
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post #14 of 39 Old 11-06-2019, 07:50 AM
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Originally Posted by AudyoVidyo View Post
This would possibly indicate phase issues between speakers, or sometimes this can occur based on the room interaction with the crossover frequency causing weird cancellations.
by lost 70% of bass it means I took out the sub completely, for the bass range down to 40hz in other words I could turn it off. then I used the receiver to lower the crossover to allow the mains to play down to 40hz I also tried full range. when I do this the spl of the bass in the sub 80hz dropped dramatically. not a phase issue or anything else just simply the speakers do not handle bass frequencies with the power that my sub can. not even close. makes sense though as a sub only does low frequencies and can do 1250 plus watts rms the titan does 1000 watts rms but for me at most they get about 110 watts for all frequencies so double that for 220 in stereo and it really makes sense that 1250 watts vs 150 watts or so at max will be a huge difference for sub 80hz frequencies. btw I know phasing is fine and tuned well as I used dirac and my brain to tune all 8 channels
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post #15 of 39 Old 11-06-2019, 11:09 AM
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This makes no sense to me.

I'd either use smaller woofers, or forget the sub and just tune the box lower, unless you listen to pipe organ or the cannon shots in the 1812 Overture.


Quote:
Originally Posted by rotgg View Post
The mains will be two bms 18n860 per side with compression driver B&C DCX464. The 18's will be ported at 32hz subs will be either devastator's, MBM 21's or skrams X 4

https://www.bcspeakers.com/en/produc...1-4/8/DCX464-8

http://www.bmsspeakers.com/Overview.1251.0.html

Noah

Last edited by noah katz; 11-06-2019 at 11:15 AM.
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post #16 of 39 Old 11-06-2019, 01:30 PM - Thread Starter
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This makes no sense to me.

I'd either use smaller woofers, or forget the sub and just tune the box lower, unless you listen to pipe organ or the cannon shots in the 1812 Overture.

Maybe your mouse took a wrong turn and you landed in the wrong section of the forum lol
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post #17 of 39 Old 11-06-2019, 06:05 PM
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Maybe your mouse took a wrong turn and you landed in the wrong section of the forum lol
I tend to agree with his assessment. Are you seeking advice or just validation?
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post #18 of 39 Old 11-06-2019, 07:11 PM
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I tend to agree with his assessment. Are you seeking advice or just validation?
Seems more like OP is doing what he/she wants, and just seeking arguments here.

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post #19 of 39 Old 11-06-2019, 08:16 PM - Thread Starter
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I tend to agree with his assessment. Are you seeking advice or just validation?

I am seeking neither. I am seeking solutions.
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post #20 of 39 Old 11-06-2019, 08:27 PM
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I am seeking neither. I am seeking solutions.

OK.

What are the requirements/performance goals?

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post #21 of 39 Old 11-06-2019, 08:30 PM
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I am seeking neither. I am seeking solutions.
Yep, ok. Good luck.
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post #22 of 39 Old 11-06-2019, 08:34 PM - Thread Starter
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Seems more like OP is doing what he/she wants, and just seeking arguments here.

Who am I arguing with? Several people in this thread have went way off topic. We usually build sealed mains with ported subs. I was going to venture down a new road and use multiple ported speakers. My questions were pretty straight forward and of course I know we can use smaller drivers etc. These are for two channel music only they must be very large! The horn we are using is 42"x29". How do you think it would look if we put cpl 7" drivers next to that horn. Again I am seeking solutions not arguments.
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post #23 of 39 Old 11-06-2019, 08:36 PM - Thread Starter
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Yep, ok. Good luck.

Thanks Guy!! Another great contribution!!
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OK.

What are the requirements/performance goals?

This room needs to be super loud. We are shooting for over 135db output. Room will be 22'x18' ish 11' ceilings. These need to be so loud it can damage your hearing loud.
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All of the drivers are purchased. We just need to build boxes.
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post #26 of 39 Old 11-06-2019, 11:00 PM
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Quote:
Originally Posted by rotgg View Post
These are for two channel music only they must be very large! The horn we are using is 42"x29".
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This room needs to be super loud. We are shooting for over 135db output. Room will be 22'x18' ish 11' ceilings. These need to be so loud it can damage your hearing loud.
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All of the drivers are purchased. We just need to build boxes.

Now you tell us.

What sub drivers do you have?

Is this actually for listening to music that loud?

Because hearing damage is the sure result.

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post #27 of 39 Old 11-06-2019, 11:15 PM - Thread Starter
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For subs looking at 4 skram or 4 devastators with loaded with b&c 21 was looking at possible 24's also with the black friday deal from SI



Yes it is believe it or not
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post #28 of 39 Old 11-07-2019, 06:18 AM
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I gave you the "solution" in the first response to your question. What else do you need to know?
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post #29 of 39 Old 11-07-2019, 11:20 AM
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You should certainly get the output.

If you're at all interested in preserving your hearing (I wish I had been when I was young; now I have to wear hearing aids but they can't restore treble very well), perhaps you could consider response that tapers down with freq.

Midrange/treble is the most damaging, but you'll be left with the bass/midbass, which is where most of the fun is at.


Believe what or not?


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For subs looking at 4 skram or 4 devastators with loaded with b&c 21 was looking at possible 24's also with the black friday deal from SI



Yes it is believe it or not

Noah
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post #30 of 39 Old 11-07-2019, 11:41 AM - Thread Starter
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Is this actually for listening to music that loud?

Yes it is believe it or not lol
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