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wgb113

Room EQ Wizard

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Long time, no blogging! We've been busy here with a new pup and I've been struggling in what spare time I have had in getting REW to work with my iMac.

After reading up on REW over at HomeTheaterShack I decided it'd be best to purchase an external soundcard to carry out the measurements. I decided to go with a unit that also had a mic preamp in it for use with my Behringer ECM8000. I decided on the Tascam US-144mkII because I didn't want to spend a ton of money and on top of being well regarded for the purpose it also had MIDI connections for use with my Behringer DEQ2496 when it comes time to EQ.

Once the Tascam arrived I had to figure out how to connect it all together in a way that would work with my iMac and active speakers. Most of the connection scenarios over on the HTS Forums deal with home theater setups with typical consumer audio gear connections. The plan was to connect everything as follows:

iMac-->Tascam via USB
Tascam RCA Line Out-->Tascam 1/4" Line In for generating a soundcard calibration file via RCA to 1/8" cable with 1/4" adapter.
Radio Shack SPL Meter-->Tascam via RCA to 1/8" cable to generate an SPL calibration file.
Tascam-->Dynaudios via RCA to XLR cable.

All cabling was hooked up and ready to go and I spent about two hours trying to get a signal from the iMac to the Tascam to no avail. No matter what settings I changed in the Sound and Audio MIDI menus, on the Tascam's Configuration Menu, in REW's Preferences, or what knobs I twiddled on the Tascam it just wouldn't work. Came to find out that it has something to do with Apple's Java Runtime support or lack thereof and multi-channel external soundcards.

A few more weeks had passed until this weekend when I finally had some time again to give it a go. I'd break out the Dell laptop and try it via a PC. With the software installed and the devices and software all configured everything was good to go. First time in a long time something was actually easier on a PC than a Mac for me!

The freq response results were pretty much in line with my other measurements as far as the peaks and nulls in the bass goes. There's some high frequency rise but I think that's more the inaccuracy of the ECM8000 at that range than anything else.

The waterfall plot is where I intend to focus my attention. My current plans are for floor-to-ceiling "superchunks" in the front corners made from Roxul Safe & Sound and then building soffits out of 2x2 wooden frames, filled with S&S, and wrapped in fabric going around the entire room. The soffit on the front wall will be 16x16 but the soffits on the other three walls will only be 9"Hx16"D due to the tops of door and window frames and a return vent.

So here are my results of the current setup:
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  1. Miska's Avatar
    There's some high frequency rise but I think that's more the inaccuracy of the ECM8000 at that range than anything else.



    Did you use the freely available ECM8000 calibration file? It's of course not accurate to the specific unit, but at least gives overall adjustment towards correct result.
  2. wgb113's Avatar
    Miska,

    I didn't for a couple of reasons. 1) I'm more interested in taming the bass issues, 2) the nearfield setup that I have negates most of the issues with the 1st reflection points up where the frequencies are, and 3) since the file wouldn't be accurate to my mic I felt it wouldn't be much better than without the file.

    The office has been de-constructed so it's too late to try it with a file now but at least I'll still have an honest comparison when I remeasure.

    Bill