Originally Posted by WaveyD4vey
alright ive owned the MBM 12 for a while now...about 7 months or so...ive owned the VTF3HO with turbo for about a year and a half...ive never really gone into detail trying to find an answer to this question before but now that ive gotten really serious about taming my frequencys with my new behringer feedback destroyer i need to know.
now whenever i use AVIA to set my subwoofer levels i first turn off the HO and have only the MBM on...i then match them to the levels of my mains...then i turn off the MBM and turn on the HO and match it to the mains...now when i go to the sub calibration part of the disc and do the same test with both subs on it reads that the levels are correct with my mains...HOWEVER, when i do a LFE sweep it reads about 10db above the level of my mains from my corssover point which is 80hz all the way down to 10hz...the second i listen to music i can tell the subs are about 10db hot.
im using a radioshack SPL meter...i also use REW...i have the crossovers set correctly on both subs so thats not the problem...im thinking it has something to do with the way avia outputs test ones.
so the way ive been calibrating my subs is this...i measure with my SPL meter (with corrected values of course) in REW...i then use the EQ filters to give me an idea of how i need to set the filters on my BFD...i then bring everything down to 75db...then when i think ive got it close i pop in AVIA and run a test tone through my speakers and make sure i have my receiver turned up loud enough for the test tone to measure 75db on the SPL meter...then i do a LFE sweep and make sure the LFE sweep doesnt deviate to much from 75db...hope all that made sense.
i know i have all the levels set up correctly i was just wanting to know if anyone else has such problems with avia or if anyone else has had to set it up this way.
The sweep tones are much louder than the test tones, they are not the same 85dB (on Avia). You have to turn the volume down when you run the sweeps. Or are you saying that when you run 200-20Hz tone, the volume jumps around the frequency where the subs take over?
If it's the latter, then the bass in the mains is down from the average SPL of the speaker (where the speaker level is matched). This could be due to the speakers themselves, room acoustics, speakers not being very close to the wall (the closer they are, the more the bass is reinforced), or a combination of these factors.
Since you have an MBM, I suggest you set the crossover in the receiver, between the speakers and the sub, much higher. Like 150Hz. The MBM is made to do that, and will give you great mid-bass. That assumes the MBM isn't behind you, because if it is, you won't want that much mid-bass coming from behind you. It will be very distracting (low registers of male voices and more).
Also, when you calibrate the HO, you MUST disable any crossover in the sub limiting the output (which you use to filter out freqs above that are being played by the MBM). You have to run the HO at its full range to set the level, because most of the bass in the sub test tone is above 50Hz. Once you set the level on the HO, then you re-engage the crossover. I hope this is how you are doing it. Otherwise the HO's level will be way too high and throw off the sound of the bass.
But make sure you are eq'ing the subs' combined output with the BFD, then re-calibrating with Avia to set the subs at the correct level. When you cut frequencies with the eq, you cut the volume, so it will be lower than before.
*And remember that Avia test tones are recorded at 85dB. If you are measuring to 75dB, that's your "-10" point. I personally use Avia and calibrate to 80dB, finding my -5 point.