QuadStacks: Sealed, locked and loaded!!!

[Mia&Lana's dad]

That's right, you read correctly. The MBM-12's now join their ULS-15 brothers in sealed configuration optimized by Dr. Hsu. The port was sealed using their standard 4" VTF foam plug along with the required internal amp modification for this orientation. I am pleased to report sound quality has been further enhanced and integration with the QuadDrive has improved significantly in terms of tonal consistency and decay. Formerly, the ULS' sonic signature caused me to notice the ported nature of the MBM's. Irregardless of flat response, I could hear a slight "hollow resonance" that was only accentuated and made apparent by the super clean ULS. That is no longer an issue for my system. I have performed a quick calibration and so far it is a wonderful addition to my setup.

[cacihome]

EH??????????????????????
What the????????????????
Sealed MBM? JEJEE
But it will then have less output around 50hz...?

[cschang]

Wow!! Interesting! Leave the back door open for me! :D

[Mia&Lana's dad]

You would think it would lose output, right? But I assure you that isn't a problem.

Curtis no problem, give me a ring!

[cacihome]

I have envy!!!

So it sounds less boxy? and unlocalizable?
jajajajaja

[cacihome]

Pete???????????
For the users with current MBM's how much will it cost the upgrade to this sealed MBM?

[john.]

Cacimar, I was gonna ask pete about this, but I just glanced at your sig and realized you may be the perfect person to ask. Would it be possible for you to get a pic of the ULS next to the 3.3? I'm very interested in actually seeing them side by side for size comparison. Maybe the 2.3 also?

[Mia&Lana's dad]

I have envy!!!

So it sounds less boxy? and unlocalizable?
jajajajaja

Would you believe that I can x/o up to 150hz.......

.....


....

NEARFIELD?!?!?!?!?

crazy man..... you only need one more to pull it off though.. Better make it a double for extra measure.... ULS/MBM

[bsoko]

Pete???????????
For the users with current MBM's how much will it cost the upgrade to this sealed MBM?

I want in on this too :D ???

Bill

[cacihome]

John.,
Two of my friends have the 2.3....I don't.
I only have the ULS-15 in my room right now. The others are in a closet.
I'll see what I can do.
But the 3.3 is very very big when compared to the ULS.
And the 2.3 looks bigger and taller also than a ULS-15.
THe ULS is just the perfect size for a sub.

[loimydog]

With this new configuration, is it safe to run it unplugged as welll? Some of us still have ported subs and might want the 'sealed sound' one day.

Pete, do you have any in stock? I'd like to pickup 2 tomorrow.

[cacihome]

jajajjaaj!!!!
The phones at hsu should be ringing a lot right now!!!!jajaaj

[bsoko]

That's right, you read correctly. The MBM-12's now join their ULS-15 brothers in sealed configuration optimized by Dr. Hsu. The port was sealed using their standard 4" VTF foam plug along with the required internal amp modification for this orientation. I am pleased to report sound quality has been further enhanced and integration with the QuadDrive has improved significantly in terms of tonal consistency and decay. Formerly, the ULS' sonic signature caused me to notice the ported nature of the MBM's. Irregardless of flat response, I could hear a slight "hollow resonance" that was only accentuated and made apparent by the super clean ULS. That is no longer an issue for my system. I have performed a quick calibration and so far it is a wonderful addition to my setup.

What is the internal amp mod?

Bill

[john.]

Thanks caci, if you break out the 3.3 I'd love to see a side by side pic. I use to have a 3.2 (I think thats about the same size as the new 2.3s), so I have an idea of how those look in person. I was just trying to get a real feel for the size of the ULS.

[cacihome]

Ok.The 3.2 and 2.3 are the same size.
Ill tell you right away that the ULS looks smaller overall.Especially in height.
it is almost a perfect 18"cube.

[cacihome]

Another question....
WIll the MBM in the future be sealed? Or will you have both products at the same time?
Can we expect higher output at higher freqs since now it will be sealed?

[Mia&Lana's dad]

What is the internal amp mod?

Bill

sealed parameters are different, so hardware modifications are required to restore the frequency response in the new orientation as opposed to just plugging it up and running it with the port tuned alignment.

[cacihome]

Yep. That is what sepparates HSU from other ID companies...
HSU subs are electronic-matched(internal eq) for their cabinets!!

[bsoko]

sealed parameters are different, so hardware modifications are required to restore the frequency response in the new orientation as opposed to just plugging it up and running it with the port tuned alignment.

Then will they be selling the modified amps as an upgrade? Pete?

Bill

[Pete_Hsu]

Would you believe that I can x/o up to 150hz.......

.....


....

NEARFIELD?!?!?!?!?

crazy man..... you only need one more to pull it off though.. Better make it a double for extra measure.... ULS/MBM

This is the beautiful thing that maybe we didn't realize until looking at your setup, Ron. As long as one has a fairly symmetrical room layout in the back of the room, then they can get truly great results using two (or more) MBM's on the left and right hand side of the primary listening position, x/o'd even as high as 150Hz.

Glad you like it! The nearfield arrangement you have right now is simply a far superior solution to what had been tried before in that room in my opinion.

[Pete_Hsu]

Pete???????????
For the users with current MBM's how much will it cost the upgrade to this sealed MBM?

I'm really not sure, I'll have to ask Dr. Hsu about this and will get back to you...

[Pete_Hsu]

With this new configuration, is it safe to run it unplugged as welll? Some of us still have ported subs and might want the 'sealed sound' one day.

Pete, do you have any in stock? I'd like to pickup 2 tomorrow.

I don't recommend running the MBM without a port plug once the amp is modified for sealed box use. Also note that it would be difficult to re-modify the amp back again for ported box use, so once sealed one will have to keep it that way.

I do think we will have a bit of an upcharge for anyone else wanting a sealed MBM, due to the added labor and extra port plug needed for the modification. I'll have to ask around about how much this will be. But in theory, as long as one is ok with a slight upcharge, then we can modify new MBM's for sealed operation, or we can take existing amps sent to us and modify them too.

Bill, we weren't planning on selling replacement amps, but rather existing amps can be modified for sealed mode operation.

[bsoko]

I don't recommend running the MBM without a port plug once the amp is modified for sealed box use. Also note that it would be difficult to re-modify the amp back again for ported box use, so once sealed one will have to keep it that way.

I do think we will have a bit of an upcharge for anyone else wanting a sealed MBM, due to the added labor and extra port plug needed for the modification. I'll have to ask around about how much this will be. But in theory, as long as one is ok with a slight upcharge, then we can modify new MBM's for sealed operation, or we can take existing amps sent to us and modify them too.

Bill, we weren't planning on selling replacement amps, but rather existing amps can be modified for sealed mode operation.

Pete, is the amp mod something we can do at home if we are tech savy?

Bill

[Pete_Hsu]

Bill, I think this is one of those times where we'll have to do the mod over at our facility.

[bsoko]

Bill, I think this is one of those times where we'll have to do the mod over at our facility.

What advantage will a sealed MBM have over the MBM ported?

Bill

[Pete_Hsu]

It's much more difficult for kids to put toys in it? Just kidding :)

One advantage is that there won't be any port resonance that comes into play, and I think that Ron was able to hear this on the ported MBM's when they were in the nearfield playing all the way out to 150Hz. A second advantage is that the combined [acoustic and electric] low frequency rolloff slope of the sealed MBM will match perfectly with the low-pass rolloff slope on the ULS-15.

[thsmith]

Pete, When you talk to Dr. Hsu you may consider making a modified version of the MBM you have today that would have a switch on the AMP plate that allows you to select open or closed port, kind of like the MO and ME switch on the 3 3.

[Pete_Hsu]

Good point Tracy, definitely something to consider!