I'm trying to set up my modest amount of gear to give me a flat response, or as close to flat as I can get. Problem is, I don't know the best way to do it.

I have a nice EQ here, but I can't find any test tone that compensate for human hearing. I.e. they sound the same level but do not actually measure as the same level.

Can any one help me here?

Thanks

Tony

You don't want to correct for your hearing. You want a system that reproduces the original sound faithfully.

If you're serious about wanting a flat response from your system, take the trouble to invest in a measuring microphone, or an SPL meter with an "unweighted" setting. This will have a flat response over the frequency range of interest (about 20-20000 Hz). You can then produce as many sine-wave test tones as you like, and tweak your EQ to suit.

Also note that unless you have ginormous speakers (meaning 18" drivers and multi-cubic-foot cabinets), you *won't* get a flat response in the sub-bass register (below about 100 Hz). It's pretty much pointless to try and correct it with EQ, either, because most speakers roll off too fast to compensate without running out of amplifier power. You'll just have to live with that.

The problem with using EQ to get a flat response from your system is that it will only work for one spot in your room. Room modes will cause the frequency response to vary quite a bit even if you only move your head a couple of inches to the left or right!

If you really want to go ahead I would suggest getting hold of a measurement mic or SPL meter with a mic output and using something like RoomEQWizard to get an idea of the actual frequency response of your room from your listening position. You can then apply a reverse EQ to compensate, but as I said above this will only be applicable for that one point in your room.

Getting a flatter frequency response in a room properly involves treating the room with bass traps and treating the first reflection points.

In general, this takes 4 pieces of equipment -

- An equalizer
- A spectrum analyzer or a Real Time Analyzer (RTA)
- A pink-noise generator
- A calibrated microphone.

Most RTAs include a calibrated microphone and pink noise generator. I have an all-in-one unit, something like this.

P.S
Human hearing is not flat and it's not linear.* And as Chromatix mentioned, you don't want to compensate for human hearing. You want to reproduce the "original sound", as recorded. You can compensate (to some extent) for room effects and weaknesses or irregularities in your speaker's frequency-response.

* The ear's frequency response (frequency sensitivity) varies with the loudness. The non-linearity is why the "loudness" control on a stereo system boosts the low frequencies (and sometimes the high frequencies) at low volumes. The famous Fletcher-Munson show the average human frequency-sensitivity at various loudness levels.