HSU Research Subwoofer Amp Model 500

[mo-x]

I run a small studio in Seattle and I'm currently using the 1220TNO with a Model 500 amp along with my KRK V8's (which are the flatest pair of studio monitors you'll probably ever hear, I love 'em for mixing vocals, but for mixing instruments especially in the bass area, they lack which is why i'm using an HSU subwoofer), my question is how do I properly adjust the amp so that it's level with everything else? If the amp volume level is too high, my mixes won't have enough low end, if it's too low they're have too much... but if I can get the level just right, it will be how I envisioned the mix to be. Any suggestions from you folks on how to properly set the amp without going the A/B route and just testing by ear?

Thanks,
Joseph Ohman

[Lwang]

I would take freq plot (w/warble or pink noise) at the listening position of both the speaker and subwoofer seperately, then pieced them together and determine what the subwoofer level would have to be so that a smooth transition would take place between the speakers and sub, w/o dips or humps in the xo region, along with the fact that the level above and below the xo point are roughly equal. If there are humps, you might want to change the xo freq of the subwoofer to something lower. If there are dips, you might want to make the xo freq of the speaker lower. You might also want to play with the phase switch to see if the dip is caused by out of phase cancellation.

If you don't want to go through that much trouble, adjust the sound level with an SPL meter in the listening position so that with the sub & speaker measured seperately at the crossover freq, the sound coming from the speaker is the same level as that is coming from the subwoofer. This might not be as accurate due to the fact since the sub will be at different position as the speakers, the response at the xo freq might be different between them relative to the rest of the freq spectrum.

[Sasha_G]

Using a Radioshack SPL Meter will be fine if you don't have an accurate spectrum analyzer or software such as ETF Room Acoustics (http://www.etfacoustic.com/).

We recommend using 1/3 octave filtered pink noise, which is provided on our test CD. If you didn't receive a test cd with your TN, we will ship you one for $5 shipping/handling. Take 3 SPL measurements using 3 of the test tones above the crossover point, and average those togeither. Take 3 measurements of 3 of the test tones below the crossover point, and average those 3 together. Your goal is to make the two averaged numbers equal one another.


The rational behind the 3 measurements is that bass response varies at different frequencies in your particular seating position, due to room acoustics.

To see bass response vary in room, try the low cost CARA program. You can map your room, and it will show the swings in the bass response.