Getting Started: Questions

Sorry for the complete newb questions, but I'm just getting started with all of this.

I've read through the entire FAQ and some relevant threads in this forum, but I want to ensure I have the basics down before I go venturing down this road.

Right now I use onboard audio from my mobo. SPDIF Optical out to my Onkyo TX-SR705 receiver.

I'm thinking of buying a M-Audio Audiophile 2496 for this (and also to hopefully resolve another problem which is that the HTPC sends only 48KHz for 44.1Khz music to the Onkyo, instead of leaving it untouched at 44.1Khz). My plan would to still output SPDIF COAX to the Onkyo's COAX input.

Anyways, I have a Radio Shack analog SPL meter and a tripod. I plan to connect the SPL meter to the M-Audio's RCA inputs using a L/R RCA cable to the SPL meter's output.

My main question arises about the instructions to connect the soundcard's RCA outputs to an RCA input on the AVR. I don't plan to use L/R analog for listening to sources from the HTPC after the calibration, so shouldn't I just be using the SPDIF COAX out during the REW calibration, rather than the requested analog outputs on the sound card?

Or, does it really matter for the calibration?


Another question I have is about making adjustments on the AVR once a measurement is taken.

Is the idea to do a measurement sweep between the following and make the stated adjustments until the peaks go away?

Examples:
1. Main speakers and subwoofer sweep - adjust crossovers to get a smooth (less than 15dB) transition on the graph through the crossover frequencies.

2. main speakers only sweep - go into my AVR's manual equalizer settings and adjust the applicable areas on the equalizer to boost or lower valleys and peaks in the measurement graph, and the retake the measurements until a smooth frequency sweep is attained.

Does this all sound accurate?

[Otto]

Hi, Joe, and welcome to the Shack.

It's fine to use the analog outs for calibration of your system. It also allows you to calibrate the soundcard itself, so that its measurements are precise. I also use a digital output from PC to preamp, and I do all my measurements with analog I/O.

The main goal is to get a nicely integrated sub response. I measure my mains for reference only, and I dont' play with the tone controls at all. Most of use measure our sub by itself, reduce peaks as necessary, then turn on the mains and make sure everything integrates nicely. If there is some weirdness at the crossover frequency, you can deal with it then.

Give it a go and see what you come up with. Sounds like you are on the right track. We'll be here when you get your first set of measurements. Good luck!