What should I do with my Sub?

[clamatowas]

I've finally finished my false wall.

However I'm left not fully understanding the best approach for my sub.

I have LOTS of the 1' square 2"thick foam that I originally planed to glue to the walls of the sub boxes. (There are 2 boxes but I only have one sub ATM).

I'm not trying to quiet the sub. I want that nice hit and no rumble. I also want low voices to come across correctly.


I read putting your subs port 6"-12" from a wall is ideal and putting it in a corner is also best.
I also read having the speaker face you is best but the sub is just to long for that given the depth I wanted to make this wall so that option is out.

To mitigate that I added a port redirect. for each sub box (See pictures)

So the question is. Do the foam, don't do the foam, only do the foam on the top and back, only do the foam against the port, ect. ect..?


Also do you think just having my sub in this 5 sided 'box' is killing me?

 

[ryanosaur]

I'm seeing so many things... I'm not even able to make sense of it all...

First... Port redirect? What is this and what do you think its accomplishing? Are you adding to the length of the Port Tube? If so, you are fundamentally altering a very specifically engineered part of the subs and speakers and changing the speakers tuning. This would be bad.

Why would you wrap your sub in foam? Seams a pointless exercise to me.

When it comes to setting up Subs, I'm an outlier and prefer the Geddes technique to all others. Corner loading subs in my room is the absolute worst thing I could do, so I know that the "Standard Recommendations" aren't always right. If you want good clean bass, you need to find the places in your room where the subs will naturally perform well. The Subwoofer Crawl is a crude but useful technique for doing that. Room measurements to back that up are great.
Its been said you can use MiniDSP and REW to overcome some of the other acoustic issues, and I know people do that, but why create those problems in the first place?

Alas, it is your rig, but those two questions above... I just don't get.

Best,
R

 

[Pogre]

I'm on my phone now, but managed to scroll through a couple of those pics. Your setup is visually impactful, but there are more audio sins than I have time to count at the moment. At a glance it appears that you are much, much more concerned about aesthetics than you are sound.

 

[lovinthehd]

I have never before seen a "port redirect"! I also wonder about the purpose of wrapping it in foam...let alone stuffing it into the wall.....

 

[Pogre]

I have never before seen a "port redirect"! I also wonder about the purpose of wrapping it in foam...let alone stuffing it into the wall.....

Or stuffing ALL of the speakers into the wall...

I think he has entirely the wrong speakers and subwoofers for what he wants. Should pull all of that out of there and go with in wall or place them how they are optimally meant to be placed. None of those speakers are designed to work well when stuffed into cubby holes like that.

*Edit: I don't even know where to start with this port redirect business. I'm baffled.

 

[ryanosaur]

This isn’t so much a false wall as a compartmentalized built-in cabinet. SMH

 

[clamatowas]

Sorry for wall of text... I'm gonna go donate to the go-fund-me after this for just making you guys read my garbage.

The "port redirect" isn't me attaching tubes to the sub. It's me giving a place for that power to go that is directed at the user.

This is my theory.


Most places I read about ports on loudspeakers and subs say the same thing. 50% of the power of a speaker is in the back out of phase.

What do do with this energy? I've read a few options:
1. You can reduce the efficiency by 50% and adsorb that energy in a way that does not create a high pressure behind the port causing a 60% reduction.

2.You can vent it out to nowhere (outside) pissing off your neighbors.

3. You can try to bring it back into phase and direct it back at the listener. Putting the ports so many inches away from hard wall is the go to for this one.


Because of my desire for a clean look, not send sound upstairs into the kitchen and rest of the house and to protect my equipment from kids I built a false wall with 3 layers of insulation around it + vibration pads between that wall and the rest of the house, it's fully isolated.

That leaves me with an issue, the ports on all my speakers are in the #1 situation listed above. So to "slightly help" this I added a way for the air to escape and be directed forward.

It's all theory but with some listening I do get an ok amount of sound from the loud speakers (see image) and a good amount of air pressure from the base using this path. I don't like the effect I can close the port.


The idea of putting the foam on top or all the sides of the Sub was to help the sound from going up to the ceiling and keeping it contained in the room. Theory: path of least resistance close to the sub, as it expands to the back of the room it's lost most of it's power and will be adsorbed/reflected by the walls and insulation I did before I fished the room.

All my crap is based on theory, based on data I find all over the place, however without the equipment to test it and tweak it.. I'm left asking.. has anyone played with any of these theory's and seen results?

So far I've just been using my ear, but that only helps me if I'm close to a good solution. If I'm miles away in the realm of. WTF ARE YOU DOING! Then I can go back to make some major changes then back to the ear test.

 

[Pogre]

What you have basically done is take a potentially nice sounding system, damped it all down and did your best to kill any HiFi Sound it had a chance of producing.

 

[Pogre]

Also, what you were doing with this redirect is extending the ports on all of your speakers. You are completely changing the tuning of your entire system and killing it.

 

[clamatowas]

Also, what you were doing with this redirect is extending the ports on all of your speakers. You are completely changing the tuning of your entire system and killing it.

So that was my HUGE worry as well. Hence the ability to plug the ports if it was just.. bad.

I've had these speakers for.. 4 + years the center and sub for 3. In two houses and always in a fully open config. This is the first time I've attempted to hide them. I moved them from a fully open room upstairs to this. Listening to all sorts of tests and music over the last 12 hours I can say that the clarity is better then I've ever herd these speakers produce. My wife who could care less if we used the TV speakers even said wow that's way better then ever...

However the sub... I'm very happy to report I get 0 audible rumbling, what I seem to lack is that low super hard punch. I do get annn ok punch just not what I'm looking for.

Also there is a 2" gap behind everything that all speakers are open to. None of the shelf's/boxes are fully sealed.
This "wall" is not really attached to the rest of the house and has gaps 1/2" top and sides and the 2" on the back before it hits the first level of more "reflective" insulation, behind that is where I'm killing all sound with several inches of real insulation.

However I'm here for your advice because I do respect it. I'll play around with removing all foam and opening things up.

 

[Pogre]

So that was my HUGE worry as well. Hence the ability to plug the ports if it was just.. bad.

I've had these speakers for.. 4 + years the center and sub for 3. In two houses and always in a fully open config. This is the first time I've attempted to hide them. I moved them from a fully open room upstairs to this. Listening to all sorts of tests and music over the last 12 hours I can say that the clarity is better then I've ever herd these speakers produce. My wife who could care less if we used the TV speakers even said wow that's way better then ever...

However the sub... I'm very happy to report I get 0 audible rumbling, what I seem to lack is that low super hard punch. I do get annn ok punch just not what I'm looking for.

Also there is a 2" gap behind everything that all speakers are open to. None of the shelf's/boxes are fully sealed.
This "wall" is not really attached to the rest of the house and has gaps 1/2" top and sides and the 2" on the back before it hits the first level of more "reflective" insulation, behind that is where I'm killing all sound with several inches of real insulation.

However I'm here for your advice because I do respect it. I'll play around with removing all foam and opening things up.

So wait, it sounds better than ever and your bass is doing what you want?


So, what advice are you seeking then?

 

[ryanosaur]

The phrase "solution in need of a problem" is what comes to mind.

Pogre is echoing my thoughts exactly.

The few rooms I've seen built by acoustic specialists DO NOT do any of these things you did. They give their speakers room to breathe and do what they were meant to do. They don't hide them in Cubbies and damp them to within an inch of their lives. They might have a false wall, but that is just a frame to support an AT screen. That's it. They smartly treat for echo, and possibly for some reflection. They also spend their time using knowledge and measurements, not making a Theory-Quilt to smother the sound.

It is not my intention to harsh on you. You clearly spent a lot of time on this... but you overthought it by a mile.

We would love to help you find a way to address your concerns. Admittedly, the things you said about "plugging the ports" or other options to "redirect energy" concern me more deeply.

How can we help you?

 

[clamatowas]

So wait, it sounds better than ever and your bass is doing what you want?


So, what advice are you seeking then?

No my base is doing.. ok.. not as good as I know it can do, hence why I'm on the sub section asking advice about the sub. I very much do appreciate the other advice and I AM going to take it and do exactly what you suggested and give it the ear test.

 

[ryanosaur]

How big is your room? Volume wise, please.
Which sub (Hsu, right, but model)?

 

[clamatowas]

The phrase "solution in need of a problem" is what comes to mind.

Pogre is echoing my thoughts exactly.

The few rooms I've seen built by acoustic specialists DO NOT do any of these things you did. They give their speakers room to breathe and do what they were meant to do. They don't hide them in Cubbies and damp them to within an inch of their lives. They might have a false wall, but that is just a frame to support an AT screen. That's it. They smartly treat for echo, and possibly for some reflection. They also spend their time using knowledge and measurements, not making a Theory-Quilt to smother the sound.

It is not my intention to harsh on you. You clearly spent a lot of time on this... but you overthought it by a mile.

We would love to help you find a way to address your concerns. Admittedly, the things you said about "plugging the ports" or other options to "redirect energy" concern me more deeply.

How can we help you?

By "plugging the ports" I don't mean on the speakers no not at all. I mean the port I added to the boxes to let the speakers breath. Maybe I should not call it a port, or a port redirect.. It's just an opening to allow that compressed air a place to go. These holes are larger then the speakers them self's and there is a hole for each speaker.

My real hope for this was do mitigate or maybe just maybe resolve the issue of "damp them to within an inch of their lives."

"How can we help you?"

You're helping a lot, I don't care that your harsh I enjoy honesty. You have all given me a lot of think about and like I said, I'm going to take that help and apply it.

 

[shadyJ]

The ported extension thing is bizarre, and it seems to stem from a misunderstanding of how vented or ported subwoofers work. The backwave acoustic radiation in a vented speaker is mostly just lost. What a port does is create a resonance using some of that backwave pressure, but only around a very narrow frequency range. That range is dictated by the dimensions of the port. You don't want to extend the ports of any speaker or sub unless you REALLY know what you are doing. A long time ago, Dr. Hsu did discuss the possibility of creating an extension for the VTF15h ports that would create more output at the lower tuning frequency, but he is a speaker scientist with a PhD from MIT. I would advise you to just use the VTF15h as he recommends in the user's manual. Once you have completed your doctorate from the most prestigious science university in the world, then maybe you can explore the possibility of altering the port tuning of your subs for improvements.

The idea of putting acoustic absorption around the speakers that are mounted in a false wall is not necessarily bad. That will help to reduce diffraction created by structure of the false wall. However, I don't think the kind of absorbers that you used were necessarily the best type for that. In either case, I doubt they are causing harm.

 

[Pogre]

No my base is doing.. ok.. not as good as I know it can do, hence why I'm on the sub section asking advice about the sub. I very much do appreciate the other advice and I AM going to take it and do exactly what you suggested and give it the ear test.

I do remember when you were much earlier in this project and we warned you that it would be suboptimal (pun intended)

I understand your desire for a nice clean look, too and I would say you achieved that. Like I said in the first post it is visually impactful. The problem is, you have entirely the wrong speakers for that type of setup. It was ill-conceived from the get-go and I wish you would have found us at the start.


I really believe if you pull everything out of there and set it up optimally it would sound shockingly better.

 

[shadyJ]

I do remember when you were much earlier in this project and we warned you that it would be suboptimal (pun intended)

I understand your desire for a nice clean look, too and I would say you achieved that. Like I said in the first post it is visually impactful. The problem is, you have entirely the wrong speakers for that type of setup. It was ill-conceived from the get-go and I wish you would have found us at the start.


I really believe if you pull everything out of there and set it up optimally it would sound shockingly better.

I don't think his speakers are necessarily bad for what he is trying to do. Why do you think those speakers are wrong for his purposes?

 

[clamatowas]

How big is your room? Volume wise, please.
Which sub (Hsu, right, but model)?

Attached is my basement floor-plan
Room = 16' at its most narrow, 19' at its most wide, 8' tall 35' long

Amp + Pre: Yamaha MX-A5200 CX-A5200 combo.
Sub: HSU VTF-15H
Center: RP-450CA
Loud: Ref IV RF82
Surround: REF IV RS42

Im using 10g for the main speakers, 16g for the surround.

 

[Pogre]

By "plugging the ports" I don't mean on the speakers no not at all. I mean the port I added to the boxes to let the speakers breath. Maybe I should not call it a port, or a port redirect.. It's just an opening to allow that compressed air a place to go. These holes are larger then the speakers them self's and there is a hole for each speaker.

My real hope for this was do mitigate or maybe just maybe resolve the issue of "damp them to within an inch of their lives."

"How can we help you?"

You're helping a lot, I don't care that your harsh I enjoy honesty. You have all given me a lot of think about and like I said, I'm going to take that help and apply it.

I think calling it a port would not be entirely inaccurate though. You have your speakers in another box. Now I'm still learning this stuff so please, anyone correct me if I'm wrong here, but is basically a resonant chamber with its own port, kind of like a speaker in a speaker... I could only take a wild guess at what all that is doing to change the response of your entire system and every speaker in it.