What should I do with my Sub?

[Pogre]

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?

All stuffed into their own cubby holes? Seems like we generally advise against that don't we?

 

[clamatowas]

This guy maybe crazy and I very well may end up opening it all up off of your advice. Honestly not that much work and it will look the same from the outside.


However most of my port theory (aka wasted speaker energy) comes from his research.

 

[ryanosaur]

This guy maybe crazy and I very well may end up opening it all up off of your advice. Honestly not that much work and it will look the same from the outside.


However most of my port theory (aka wasted speaker energy) comes from his research.

I've seen some holes poked in his methodology. Also, as I understand CLD, his method is flawed... That's neither here nor there... but do not waste time building Voigt Pipes. Even Voigt himself knew it to be flawed and not worth building.

Back to the main show.

You definieltly need another VTF15 (just buy two more , you'll thank me down the road!). Personally, I would encourage you to crawl it out and get your subs off the front wall. Again, that's just me, but at roughly 5000'3 in your room, you can have the subs perform much better if they are placed strategically in your room, and backed up with measurements. A Umik-1 from MiniDSP and the freeware REW download, and you can be in much better control!

 

[Pogre]

This guy maybe crazy and I very well may end up opening it all up off of your advice. Honestly not that much work and it will look the same from the outside.


However most of my port theory (aka wasted speaker energy) comes from his research.

I think I've seen that video before. It was a fun watch. However, IIRC he's talking about transmission line speakers. That is a whole other animal from ported speakers and a lot more difficult to get right. You really have to know what you're doing to design and build one of those.

 

[Pogre]

I've seen some holes poked in his methodology. Also, as I understand CLD, his method is flawed... That's neither here nor there... but do not waste time building Voigt Pipes. Even Voigt himself knew it to be flawed and not worth building.

Back to the main show.

You definieltly need another VTF15 (just buy two more , you'll thank me down the road!). Personally, I would encourage you to crawl it out and get your subs off the front wall. Again, that's just me, but at roughly 5000'3 in your room, you can have the subs perform much better if they are placed strategically in your room, and backed up with measurements. A Umik-1 from MiniDSP and the freeware REW download, and you can be in much better control!

Okay yeah. I did not recall correctly. I was thinking they were TL speakers he was building.

 

[shadyJ]

All stuffed into their own cubby holes? Seems like we generally advise against that don't we?

It's true that placement isn't optimal for sound, but he wanted a false wall, and it's not easy to do that without degrading the sound to some degree. At least he put damping material around the speakers to mitigate diffraction. Anyway, it looked to me like your were criticizing the type of speakers he used for that project, however, those speakers are probably not that terrible for that type of use compared to other speakers he could have went with. I agree though, he has made a lot of mistakes however.

 

[clamatowas]

I've seen some holes poked in his methodology. Also, as I understand CLD, his method is flawed... That's neither here nor there... but do not waste time building Voigt Pipes. Even Voigt himself knew it to be flawed and not worth building.

Back to the main show.

You definieltly need another VTF15 (just buy two more , you'll thank me down the road!). Personally, I would encourage you to crawl it out and get your subs off the front wall. Again, that's just me, but at roughly 5000'3 in your room, you can have the subs perform much better if they are placed strategically in your room, and backed up with measurements. A Umik-1 from MiniDSP and the freeware REW download, and you can be in much better control!

I do plan on getting another sub, still need get the 4k projector and the 4 new presence speakers. Wife is... not mad yet so we will see how far I can push it.

I'll get that Mic ordered and see what I can learn from that. What's your option on the.. topic of issue. Main speakers being sealed in the front, open in the back? Open all the way or shouldn't cause that big of an issue?

 

[William Lemmerhirt]

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.

Not sure if you were around yet, but I remember these “turbo” kits from HSU.
Just think if Blose would’ve thought of these...
it’s actually genius I think.

 

[ryanosaur]

Okay yeah. I did not recall correctly. I was thinking they were TL speakers he was building.

They are a Flared Transmission Line design, where the closed-end surface area is 0, flaring wider along the line. This type of design gives higher output and a lower tuning frequency at the cost of being the longest line to build, and it is much harder to damp the destructive harmonics inside the line. Changing the starting surface area to 1 (being equal to the Driver Sd) and flaring to a ratio of 3-4x larger at the open end helps tremendously with some of the fundamental flaws of the design, but still not enough to make it worthwhile.

 

[William Lemmerhirt]

I’m curious how the attempt at remaining quieter throughout the house has been. IMO the front waves would still carry through the house especially at volume. Also, I’m guessing the newfound “clarity” has more to do with the new rooms furnishings and carpet and other accidental acoustic benefits, than the wall of foam. Huh, that sound like fun!

 

[Pogre]

It's true that placement isn't optimal for sound, but he wanted a false wall, and it's not easy to do that without degrading the sound to some degree. At least he put damping material around the speakers to mitigate diffraction. Anyway, it looked to me like your were criticizing the type of speakers he used for that project, however, those speakers are probably not that terrible for that type of use compared to other speakers he could have went with. I agree though, he has made a lot of mistakes however.

I don't know that I would consider what he has a false wall. It's more like an entertainment center full of cubby holes. I agree that they are not the most horrible speakers but to plan and build a setup like that around them I think it was a mistake.

 

[ryanosaur]

Huh, that sound like fun!

A wall of foam padding? It does, doesn't it. We all gon' need it if we don't get out soon!

 

[shadyJ]

Not sure if you were around yet, but I remember these “turbo” kits from HSU.
Just think if Blose would’ve thought of these...
it’s actually genius I think.
View attachment 35285

I used to have one. It wasn't really worth the hassle unless you owned the VTF3 HO. Like I mentioned, Dr. Hsu discussed the possibility of doing one for the VTF15h awhile back, but it would have been a bit involved and cumbersome, even more than the turbo module for the VTF3 series was.

 

[shadyJ]

I don't know that I would consider what he has a false wall. It's more like an entertainment center full of cubby holes. I agree that they are not the most horrible speakers but to plan and build a setup like that around them I think it was a mistake.

Yeah, I agree. He should have arranged it to be more like a false wall than enclosed cubbies. It certainly isn't optimal for sound quality.

 

[Pogre]

I used to have one. It wasn't really worth the hassle unless you owned the VTF3 HO. Like I mentioned, Dr. Hsu discussed the possibility of doing one for the VTF15h awhile back, but it would have been a bit involved and cumbersome, even more than the turbo module for the VTF3 series was.

If Doctor Hsu comes out with a turbo for the vtf-3 MK5 I am going to clog these forums up with so many posts...

 

[William Lemmerhirt]

I used to have one. It wasn't really worth the hassle unless you owned the VTF3 HO. Like I mentioned, Dr. Hsu discussed the possibility of doing one for the VTF15h awhile back, but it would have been a bit involved and cumbersome, even more than the turbo module for the VTF3 series was.

Seems like it was confusing for normal consumers too. For nerds like us though, even academically speaking, it was pretty cool.

 

[clamatowas]

I’m curious how the attempt at remaining quieter throughout the house has been. IMO the front waves would still carry through the house especially at volume. Also, I’m guessing the newfound “clarity” has more to do with the new rooms furnishings and carpet and other accidental acoustic benefits, than the wall of foam. Huh, that sound like fun!

Better then I would have thought, I turned it ALL the way up even the base and it was SOOO loud in the main room. The baby was sleeping upstairs and I went into her room.. I had to really try to hear it ... My wife in the master could hear a low base but it was so quiet any white noise 100% masked it. In the kitchen right above the floor, you can kinda of hear it and the sub will give your feet a little massage if you stand in the right spot. But it's less noise then having my google home mini playing musing @10% volume.. So I would say.. way better then I thought success.

The two downstairs bedrooms you can hear it but it is extremely muffled. with a fan going I bet the baby would not even wake up in either basement bedroom.

What does this mean, at 2am I can watch a movie at very loud and not worry about the wife getting angry.

 

[ryanosaur]

What does this mean, at 2am I can watch a movie at very loud and not worry about the wife getting angry

If you're watching a movie at 2AM... she won't just be angry, she will be the Dark Side of the Force!

 

[Pogre]

Better then I would have thought, I turned it ALL the way up even the base and it was SOOO loud in the main room. The baby was sleeping upstairs and I went into her room.. I had to really try to hear it ... My wife in the master could hear a low base but it was so quiet any white noise 100% masked it. In the kitchen right above the floor, you can kinda of hear it and the sub will give your feet a little massage if you stand in the right spot. But it's less noise then having my google home mini playing musing @10% volume.. So I would say.. way better then I thought success.

The two downstairs bedrooms you can hear it but it is extremely muffled. with a fan going I bet the baby would not even wake up in either basement bedroom.

What does this mean, at 2am I can watch a movie at very loud and not worry about the wife getting angry.

If you haven't already, you should pull the sub out of there, set it up in a more standard location in that same room and see how much difference all of your damping made.

 

[William Lemmerhirt]

If you haven't already, you should pull the sub out of there, set it up in a more standard location in that same room and see how much difference all of your damping made.

And also see how much more impact it has.