OFFICIAL Hsu MBM-12 thread - Page 6

John, cool setup! Mine's in the living room so no chance of setting up for the best room acoustics.

Bill

Thanks!

John, try putting the MBM-12's sideways directly behind the listening position, with amps back to back (maybe 1 or 2 inches of space in between the amps). Depending on the construction of the couch, sometimes people prefer not having the port fire directly into the couch.

Pete,

Will give that a try. How much space between MBM's ports and HGS-18's sides?

John

Yeh, but having them firing into the back of the couch is like having a butt kicker. I like to feel the bass!

Bill

How do you run Audessy if you have 2 subs----one VTF-3.3 in the front corner, and one MBM behind the sofa?

Do you do it one sub at a time? And if so how?

Once your subs are set up then run your reciever EQ program.
After Audessy is run, then check your subs db and retune to your taste.

Bill

Hi John,


You probably don't need more than 3-4" of space in between the MBM ports and the Velodynes.

It's ok to have the MBM-12 oriented with ports firing into the couch (and a little spacing in between), or even oriented 180 degrees where the port fires directly away from the couch. I usually recommend that people experiment with the orientation.

The couch we have in our demo room has some mechanical parts in it, so I find it a little distracting to have the MBM port fire into the couch. But with other couches it may not pose an issue. So I suppose it is best to try out some different configs!

Sincerely,

That is definitely true Bill!

John

John - want to add a little more mid bass for those explosions and gun shots, helicopter blades rotating, etc. change the xover on the true sub to around 55-60hz. It does bring up the mid bass and ads to the depth of it.

Bill

If I decide to change the crossover do I need to recalibrate the subs and run audyessy again?

Hey Peter or whomever may help.
I just added a mbm12 to my Vtf ho w turbo.
Now i need to get everything setup to tear the house down.
I have only gotten my ho setup to where i was happy with it about a week ago as per Dr hsu's emails,the main thing we changed was putting the ho into a little "under the stairs"utility room in the front right corner of my room,by doing this i got to drop the ho gain from about 2 oclock to 11 o clock with still more low end.
Well now ive added the mbm behind the couch and recalibrated and messed up everything ,so here i go again.
Ive got the ho xover switched to "in"set at 50 hz,the mbm xover switched to "in set at 100 hz and the receiver xover set at 100 hz.
I set the volumes with the subs gain at about 11 oclock on both,using your spreadsheet i found online and the radio shack spl ,the subs checked one at a time then together.subs are set at about 85-89db compared to 75db on all other speakers.
One question,when setting the speaker volumes(fronts ,center ,etc)ive always just went to the front left for example then turned up the receiver volume until speaker is at75 db,then set everything else to match.
Then im at approx.-20 to -30 (volume on receiver)when watching movies.
Speakers are set at approx.+5 to +8 db to acheive 75db.
If i were to turn the receiver volume to say zero and then calibrate all speakers to 75 db (this im sure would have me setting speakers in the -10 to 20 db range)would this make any difference in the overall "blending of speakers and subs?"
Sorry for the long post but im back to serching for the "chest thump" i want from the mbm.I do now have the "shake the house" lowend that Dr hsu helped me find a couple of weeks ago.
Thanks
Dean
Ive included a rather cheesy if not less than impressive diagram of my ht room.Overall dimension of room is 23x 23 plus utility room and stairwell,8 foot ceiling.
This room is a basement room on slab foundation with concrete block walls covered in tonque in groove pine,no drywall,no windows,drapes or wall hangings,i know i need to do the room treatment,bass trap thing but im not there yet.My lack of "bass slam"is do im sure to the room not equipment but is there anything you see that you would suggest changing?
Thanks
Dean

I picked up some 2.10" brass spikes to replace the MBM-12's plastic tapered feet. I haven't installed them yet.

John

jd, you should set the MBM-12 crossover switch to 'Out' to bypass the MBM's crossover and make use of the bass management features on your receiver (including crossover, distance, and level). Set the sub crossover on the receiver to ~ 80Hz, and set the sub distance equal to the distance between your listening position and the MBM.

Sincerely,

John, those things look wicked! Wow...

How is everything sounding now with your new config?

Pete,

I just finished testing the Conquests. I started with both colocated in the front left corner of the room. I now have one positioned in each front corner. I am now going to integrate the MBM-12's back into the system. I will position them were I have my HGS-18's now. One just to each side of the recliner. I have some room treatments coming from GIK Acoustics. One is their Monster Bass Trap that will go behind the LP on a stand.

John

Where did you find these ?

2.10" Brass Floor Cones / Speaker Spikes

M6 thread size for the MBM-12

The stud is not as deep as the one on the factory legs but thread in a few turns.

John

Oh OK.
But i still want the ho xover set to "in" correct?
If both subs are connected with a y cable to the receiver,the ho xover in and at 50hz and the rec set at 80hz are the ho and mbm not both playing at 50hz down?how is the mbm getting cut off at 50 hz?
Sorry for the ignorance.
Dean

Parts Express has a set of 4 speaker adjustable spikes for $20 in gold or black chrome.

Bill

Dean - go to this site: http://forum.hsuresearch.com/showpos...9&postcount=33.

Bill

Bill,

They are only 1-1/2" tall. The feet on the MBM-12 are 2". That might make a difference since it is down firing. I couldn't see any reference to the thread size. It is most likely standard 1/4-20 not the required M6.

John

Yes, you want the HO crossover switched in and set to roughly 50hz, but you can experiment with both the crossover setting and the phase on the HO to create the smoothest transition to the MBM-12 in your room/system.

The MBM-12 has a built-in filter to roll off the frequencies below 50hz.

Cheers,
Ross

Yup. lol Using my radioshack spl meter and some test tones from the diy calibration disc. I found out my mbm-12 is very strong to 30 hz behind the listening position. With a dip at 50-55hz. I think i'm going to have to get something to roll it off more lol. With the test tone between 93db and 95db from 60hz to 80 hz its so flat with only the mbm-12 on. But I also get 93 db at around 40 hz and 45hz.

Was your measuring done with only the MBM-12 playing, true sub and mains off? If so you are getting some tough room issues in that placement.

When setting up mine behind the listening seat I varied the receiver's sub distance setting (which acts as a phase control) in 1/2ft incrememts unti I got the best midbass response and smothest transition to the mains crossed at 80hz, then I turned on the true sub and used its continuously variable phase control to match the transition at the low end. All this was made easier by watching the real-time changes on my tv from the SMS-1 graph.

Cheers,
Ross

Don't feel so bad. Here is what I am getting from my MBM. My main sub xo is set to 30Hz and I am still getting a spike at 50Hz. The MBM is nearfield on the right side of my couch.

Yup, that's right jd, set the HO crossover switch to 'In', and the crossover knob on that sub somewhere in the 45-50Hz region. Note that the MBM-12 rolls off naturally below 50Hz (combination of port tuning and subsonic filtering), so you don't need to do anything to cut off the lower frequencies from the module.

That is with everything off and only the mbm-12 on. Is the Sms-1 that $600 eq with a mic? Everything is pretty flat except i have a dip around 50-60hz.
I have no room treatments either. I think Ima save up for some bass traps or something. Will bass traps help with a dip around 50-60hz and a peak at 40-45 hz?

How do you make graphs on the computer. I have done them manually on some notebook paper. Will excel work? I also have rew but have no clue how to use it, and my sound card and inputs don't work since i have vista now.