Bi-Amping: How can I determine relative output?


Long Story Short:  I have a 50w/channel pair of tube monos, and a 300w stereo solid state amp playing through a set of JBL 4367s. two way monitors.

The tubes are on the horn tweeter and the solid state is on the 15" woofer, crossover is apparently 700hz.

Doing absolutely nothing, some music sounds completely "normal" and some music sounds artificially bass heavy.

The solid state amp has gain adjustments for each channel.

I have a Fluke 115 multimeter, and access to plenty of test tones, but nothing to read SPL.

Is there a way to measure output at the speaker terminals such that I could dial the woofer amp down to "match" the tube amps?

If so, would this be more or less constant as the preamp driving the amps changes  volume, or would it only "match" (to the extent that it actually matches at all) at one volume level?

 

 

 

gthirteen

SS Amp has a right and left gain controls.  Using the Fluke, is it possible to measure at the speaker outputs (if so what would I be measuring) in order to get the right/left levels the same?  
 

A little background- the tube amps are plenty for normal use, and sound great.  I’ve been having an itch to run the JBLs at ridiculous levels, so I bought a Parasound A21+ to play with. It sounds great and the combo allows for wall shaking sound, but isn’t as smooth as when using the tube monos. 
 

I noted the gain controls on the A21+, and set out to try a biamped setup.  Given that the speaker is a two way with a pretty low crossover, I though that it may be possible to get decent sound.  With zero adjustment, it sounds much better than I expected.  Currently using the line level pass through on the Parasound, however I have a spare set of the IC I’m using and plan to try connecting to the 2nd output of my line stage.

if there were some way to get both sides adjusted as to some actual metric, not by ear or according to SPL, I’d love to start from that point, and tweak if necessary.

OP:

I gave you the solution! :)  Find a 60 Hz tone, play it and measure the amplifier's output.  The only problem you might have is if your tube amp is has the higher gain. 

Multimeters perform best at 50-60 Hz.

@erik_squires  Voltage out does not equal SPL out. You may get the amps giving the same output but differences in driver efficiency will make the SPL different.

@russ69 - Assuming passive biamping, meaning the original crossover is still in place, SPL matching is done in the speaker's crossover.

Did I misunderstand the OP's problem?

@erik_squires Oh shoot I was thinking about the way I do it with an outboard crossover. You are right.