MBM ETA

[Bill S]

Pete do you have a date on the new MBM?

[Pete_Hsu]

Bill, I heard recently that production has started. So I anticipate that we will have them by end of October.

Sincerely,

[mystik610]

Will the new MBM be available in the real wood finishes?

[myspark1]

If they come in Walnut, I am *so* there! Of course, I'll likely be there no matter what.

---- Mark

[skool]

Pete, beside the new VTF feature, is the new MBM-12 uses a brand new driver or improved/updated driver? How soon can we see some pictures of prototype? Also, what's the confirmation on premium veneer finishes?

[Pete_Hsu]

Guess what guys, I've heard that the MBM-12 MK2 will be available for purchase sometime next week!

The finishes that we will have include:

Satin Black
Rosenut Wood Veneer
Walnut Wood Veneer
Espresso Wood Veneer
Maple Wood Veneer --> will be available within 1-2 weeks from now


Note that the driver and enclosure is the same as the original MBM-12.


Sincerely,

[skool]

That's great news! What will be the pricing?

[mystik610]

I'm seriously considering the MBM and will probably get one eventually, just wondering what the best way to integrate it into my system would be.

I'm in a large room and using a nearfield placement for my VTF-3. If I were to get an MBM, should I use a nearfield placement for the MBM as well? I'm feeling that my system is lacking in the mid-bass department, and would probably prefer to set the LPF on this thing to 120hz to bolster the mid-bass in my fronts. This of course would make the sub sound very directional, so I'm wondering if a far-field placement near the fronts would suit me better.

[Pete_Hsu]

That's great news! What will be the pricing?

The price should be ~ $549 for Satin Black, and ~ $649 for Real Wood Veneer.

Note that Hsu Research subwoofer owners are also eligible for a $50 instant discount.

Sincerely,

[Pete_Hsu]

I'm seriously considering the MBM and will probably get one eventually, just wondering what the best way to integrate it into my system would be.

I'm in a large room and using a nearfield placement for my VTF-3. If I were to get an MBM, should I use a nearfield placement for the MBM as well? I'm feeling that my system is lacking in the mid-bass department, and would probably prefer to set the LPF on this thing to 120hz to bolster the mid-bass in my fronts. This of course would make the sub sound very directional, so I'm wondering if a far-field placement near the fronts would suit me better.

With a single MBM-12, I would put it in the nearfield next to your VTF-3 MK3. Run the MBM in the 'Sealed' mode, and set the low pass crossover knob on the -3 MK3 to ~50Hz (with crossover 'In' on the -3 MK3).

Sincerely,

[bsoko]

Anybody purchasing a MBM for their system and have a True Sub, there is only one way to calibrate them together:

Here is how you properly calibrate a sub and an MBM, by Cyberbri:

--With the sub off, calibrate the MBM to the same level as the speakers
--With the MBM off, and the sub's xo switched off, calibrate it to the same level as the MBM and the speakers
--The above two steps match the level of the two subs to the same level, because you are matching their output at the same frequencies in the sub test tone
--Engage the sub's xo, turn both subs on, and calibrate the combined output of the sub and the MBM to match the level of the speakers

Then I would check with a sweep tone (like on Avia) or REW to make sure the transition between the subs is smooth, and do a lot more to tweak. But that's beyond standard level-matching calibration.



However, if you do it this way...

--With the sub off, calibrate the MBM to the same level as the speakers
--With the MBM off, and the sub's xo switched on, calibrate the sub to the same level as the MBM and the speakers
--Then calibrate combined MBM and sub (xo on), lowering level to match that of speakers...

...then the test tone that is meant for subs in the higher bass range (60~100Hz) has much of the energy cut out by the sub's xo. This means that the measured volume is reduced, making you turn up the sub's gain to match the same SPL to compensate. Basically you are trying to have the xo'd sub play as loud in the filtered out frequencies (due to the engaged xo) as the MBM itself is playing - even though the sub is supposed to handle the lower freqs while the MBM handles the mid-bass. This can put the sub much too high - 4~10dB or more too hot. When I tested using Avia's test tones (not the receiver's), engaging my Hsu sub's xo at 50Hz reduced the volume by about 5-6dB. Depending on the test tone the receiver puts out (how much bass falls below 50~60Hz), it could make an even bigger difference.

That's if you're trying to accurately calibrate the two and level match them.

Plus... The additional SPL in the freqs above the xo coming from the sub (when calibrated with the xo turned on) means there's more SPL in the range where the MBM is supposed to be doing all the work. And when the output above the xo combines from the sub and the MBM and is boosted (hopefully not cancelling out at certain frequencies due to phase issues, causing holes or dips), you then have to turn down the combined calibrated SPL level because it's now too loud. So you may just be back to where you should be below the xo point (had you calibrated the correct way). Only this time, even though the combined calibrated SPL level is the same, the sub is doing more work above the xo than it's supposed to be doing and the MBM is outputting less SPL in its dedicated range (and in higher freqs if you have it crossed with the mains higher than the average 80Hz - some people cross as high as 150Hz - this would reduce the output all the way up to there), sort of defeating the purpose of having the MBM do the higher bass freqs for more slam in the first place.

If you calibrate correctly, with the first method, then theoretically you shouldn't need to adjust the combined level of the MBM and sub because they properly level-matched and are crossed over with overlapping slopes around 50hz. There might be a little variation in the combined SPL level, but with the combined slopes there shouldn't be too much variation if they're in phase and it's set up correctly.

It's the same for speakers -- individual drivers alone slope off at certain frequencies (you can easily see by looking at the measurements for the individual drivers), but the xo's are designed so that the slopes overlap and maintain a flat response.



People definitely like more bass in the low end, which is why house curves are popular. Room gain usually gives you enough of a house curve to not need to artificially boost the low end, although people do like to include a house curve when they eq (cutting the higher bass frequencies and leaving the boosted low end - no boosting past original levels - when you eq, you cut to make it flat, then increase the overall level). A gain of 10+dB or more down to 20hz or so isn't uncommon in a house curve. That comes from room gain usually, and/or eqing (cutting frequencies) for a smooth rise from higher bass freqs to the lower. It takes higher volumes to sound the same "volume" the lower you go.

To get a house curve with a sub and MBM, I'd do a house curve on the sub so there's the rise below 30 or 40hz or whatever, then adjust the MBM to transition with the sub smoothly at the xo point. Some people like a big curve all the way to +/- 100Hz, but I personally listen to a lot of music and like accurate bass. Flat bass (especially with bass traps) sounds amazing with music. My house curve is slight, with the rise below 40hz or so smoothed out, but the rest is very flat. This gives me more low end boom for movies but it doesn't color the higher bass and makes music sound extremely smooth and natural.


Using the second/lower method to calibrate can be used to calibrate for a boosted low end, but it won't give you an accurate "calibration." You can use it to "calibrate," this time meaning "a way to set your levels," and may help get a house curve effect. But it's not "accurate" and, like I said above, could lead to the sub playing more above 50Hz and the MBM playing less, somewhat defeating the purpose of having the dedicated mid-bass driver and lightening the load from the low end sub.

The first method, with the sub's xo disabled for level matching, is the correct way to level match and get an accurate baseline from which to boost to taste, eq for house curve, etc.

This info if from HSU - Calibrate A Sub With A HSU MBM-12 Mid Bass Module By Cyberbri (http://forum.hsuresearch.com/showpost.php?p=33939&postcount=33).

Bill

[skool]

With a single MBM-12, I would put it in the nearfield next to your VTF-3 MK3. Run the MBM in the 'Sealed' mode, and set the low pass crossover knob on the -3 MK3 to ~50Hz (with crossover 'In' on the -3 MK3).

Sincerely,

I am sorry Pete if I have missed this, but what's this "Sealed" mode are you referring to? How many VTF modes does the MBM-12 Mk. 2 offer? What's the advantage of this "Sealed" mode versus the standard "Maximum Output" mode?

[Pete_Hsu]

I am sorry Pete if I have missed this, but what's this "Sealed" mode are you referring to? How many VTF modes does the MBM-12 Mk. 2 offer? What's the advantage of this "Sealed" mode versus the standard "Maximum Output" mode?

Hi skool,

The MBM-12 MK2 has two operating modes: 'Sealed' and 'Ported' modes.

The advantage of the 'Sealed' mode is that, when placed near or next to the true subwoofer, the 24db/oct low frequency rolloff of the sealed mode matches perfectly with the 24db/oct low-pass crossover network on our true subwoofers. So blending between the two units is arguably better.

The advantage of the 'Ported' mode is that driver excursion demands are reduced near port tuning, and there will be a bit more output at some frequencies.

So we include a 4" port plug and a switch on the MBM-12 MK2 amp so that one can easily switch back and forth between 'Sealed' and 'Ported' mode simply by adding or removing the foam port plug and flipping the operating mode switch on the back of the sub.

Sincerely,

[Pete_Hsu]

To set up the MBM-12, here is one easy way to do it with an SPL meter and our test tone CD:

1) Set the volume knob on the MBM-12 to ~ 9 o'clock, with crossover 'Out'
2) Set the volume knob on the VTF subwoofer to ~ 9 o'clock (set ULS and STF subwoofers to ~ 11 o'clock), with crossover 'In' and crossover knob set at ~ 50Hz
3) Set crossover frequency (let's use 80Hz for this example) and distance setting for all speakers/subwoofer on the receiver. Note that the subwoofer distance on the receiver should be set to the distance between the main listening position and MBM-12.
4) Place the SPL meter at the listening position, ear level, "C" weighting and "Slow" settings
5) Set master volume level on the receiver so that the SPL meter shows 80db using the 63Hz test tone with speakers/MBM/true subwoofer all on
6) Play the 1/3 octave spaced test tones between 31.5-200Hz on the test tone CD, and record the SPL at each frequency
7) Adjust the volume knob on the true subwoofer so that the average SPL for 31.5Hz/40Hz/50Hz is the same as that for 50Hz/63Hz/80Hz. Note that one can try inverting the phase on the true subwoofer to see if that gives a flatter response
8) Adjust the subwoofer channel level on the receiver so that the average SPL for four frequencies directly below 80Hz (ie. 31.5Hz/40Hz/50Hz/63Hz) is the same as that for four frequencies directly above 80Hz (ie. 100Hz/125Hz/160Hz/200Hz). Note that one can invert the phase on the MBM-12/true sub combo to see if that gives a better transition with the main speakers near the crossover frequency.
9) Now you are all set! To adjust the combined MBM/true sub volume in the future, simply adjust the subwoofer channel level on the receiver upward or downward in 1db increments

Note that I prefer to do the level matching with speakers/MBM/true subwoofer all running at the same time so that I can get a good representation of the system response with everything running at the same time.

[skool]

Hi skool,

The MBM-12 MK2 has two operating modes: 'Sealed' and 'Ported' modes.

The advantage of the 'Sealed' mode is that, when placed near or next to the true subwoofer, the 24db/oct low frequency rolloff of the sealed mode matches perfectly with the 24db/oct low-pass crossover network on our true subwoofers. So blending between the two units is arguably better.

The advantage of the 'Ported' mode is that driver excursion demands are reduced near port tuning, and there will be a bit more output at some frequencies.

So we include a 4" port plug and a switch on the MBM-12 MK2 amp so that one can easily switch back and forth between 'Sealed' and 'Ported' mode simply by adding or removing the foam port plug and flipping the operating mode switch on the back of the sub.

Sincerely,


Thanks for the quick informative reply. In your testing, do you always find that MBM-12 works better in 'Sealed" mode when placing next to another sub or does that depends on other variables as well?

In 'Sealed' mode, how much lower in output are we seeing from 50 Hz to crossover point generally?

Subjectively speaking, does 'Sealed" mode sounds better?

[Pete_Hsu]

Hi skool,

To be honest, I really haven't had a chance to play around with the MBM-12 MK2 much. Hopefully you guys will be able to provide some good feedback when you get them in your hands!

The max output difference will be fairly minor most of the time, maybe up to 1 or 2 db difference depending on frequency.

Sincerely,

[skool]

Oh, I see. Thanks for your honesty. Is the development process being done by Dr. Hsu himself before final release to your facility?

I am sure the 'sealed" feature is a great option for those who will use it. Why else would Dr. Hsu implement such feature if it wasn't "better" in some way. I look forward to some great reviews coming out soon.

[Pete_Hsu]

We already did the research and development on the MBM-12 MK2 some time back. So the production-ready model will be available for purchase possibly by this weekend :)

Thanks

[sethhobrin]

C'mon Pete. Your just being humble cause you know this thing is going to shatter our rib cages :)

Question: is it wireless?

[Pete_Hsu]

Hi guys,

Here are the details on the MBM-12 MK2:

Regular price will be $549 for Satin Black, $649 for Real Wood Veneer Rosenut/Walnut/Espresso/Maple. Shipping is $39 flat rate anywhere in the continental USA (Alaska, Hawaii, and international customers should email sales<at>hsuresearch.com for a shipping quote).

For a limited time, starting now, we will be offering a $50 instant discount on all finishes, regardless of whether or not one owns a Hsu subwoofer.

In the future, once the intro pricing period is over, then we will offer a $50 instant discount off regular price to anyone who has purchased a Hsu Research subwoofer from us.

seth, just to clarify, the MBM-12 MK2 does not have wireless connectivity.

The webpage for the MBM-12 MK2 will not be up until mid-to-late next week. So if anyone wants to order now, feel free to call us (our direct line is 714-666-9260).

Thanks!

Sincerely,

[Pete_Hsu]

Hi all,

Just wanted to give you the heads up that the MBM-12 MK2 webpage is up, with the introductory prices reflected:

http://www.hsuresearch.com/products/mbm-12mk2.html

Hopefully we will have some pictures up within the next week or so.

Thanks

Sincerely,