# Question about level matching after BFD



## Dr. Spankenstein (Aug 4, 2006)

After attempting to equalize my sub, my graph looks great (averaged from 5 positions), then I take a full-range reading and the mains appear to be 10dB down. 

Sub trim is already at -7.5dB and the sub level knob is at 10 o'clock already. 

When I took my REW measurements, the MV was at -32 and it was reading 84dB @ 20Hz (I have a +9 house curve shelved at 20Hz) 80Hz measured 75dB and all other frequencies tracked the target slope.

Now I didn't get a chance to check the input level on the BFD after my EQing, but my concern is that I won't be able to adjust the sub down enough to match the mains. (per my AVR sub trim and sub level/volme knob settings)

While I'm somewhat aware that the sub level knob is used to match the signal voltage, most of the people's input on this sub have the knob at no less than 10 o'clock (stating the amp doesn't "kick-in" until they raised it) 

Will I still be OK if I have to drastically reduce the level knob to match the mains. This (to me) sounds like a question for someone who is familliar with the voltage requirements.

As info, my sub is an eD A7s-450 (18" sealed) run from an Onkyo 805.

Thanks in advance.


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## Wayne A. Pflughaupt (Apr 13, 2006)

> Sub trim is already at -7.5dB...


Without knowing the range of adjustment, that information isn’t terribly helpful.  




> Now I didn't get a chance to check the input level on the BFD after my EQing, but my concern is that I won't be able to adjust the sub down enough to match the mains. (per my AVR sub trim and sub level/volme knob settings)


 Hope this doesn’t come off as rude or abrasive, but why not try and see if you can actually make the needed adjustment before getting worried about it?

Did you use a lot of boosted filters? If you’re getting a hotter signal to the sub than before equalization, that would explain it.

Regards,
Wayne


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## Dr. Spankenstein (Aug 4, 2006)

Whoops! I did neglect to mention that the sub trim on the AVR can go to -15dB. 

My concern comes from prior comments on the sensitivity of the LT1300 amp. You're right though, I should check BEFORE asking. 

My question, in a general sense, was more about signal strength, which I know nothing about. I also have an inquiry in the eD forums to ask about minimum gain settings on the amp.

Thanks for responding.


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## Zeitgeist (Apr 4, 2009)

By "kick in" - do you mean power on? Some subs have power-on-signal power settings.. You can disable depending on the mfg.

Or just be audible?

When the sub(s) are EQd to match mains - the sub(s) may sound a little muffled... but everything works out when playing movie content.

But at the same time, I found multiple subs at 75 db sounded louder than a single sub putting out 75db.


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