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I recently purchased the miniDSP UMIK-1 USB Microphone and have been playing with the settings in REW at various points in my family room.

I have a few basic questions:
  1. What does the ideal curve look like for non-sub speakers? I saw some references to flattening the curve and others referring to a gradual step-down. Any guidance here would be great.
  2. I see a lot of posts referencing to overlay the "ideal" curve over the graph to make it easier to determine where to make boosts. How do I apply such overlay to my graphs? My receiver allows me to adjust each channel independently for 63/160/400/1k/2.5k/6.3k/16k Hz.
  3. Is it normal to see this many dips in a non-smoothed graph?
  4. I believe I've heard clipping on some of the speakers during the measurements, what's the best way to address that? Should I look into getting a separate amp for my Front Left/Right leveraging the pre-amp outs from my receiver?
For reference, I'm running a 5.2.2 setup with the following equipment. I've excluded the sub from this graphs to focus this on the non-sub speakers.
  • AVR: Yamaha TSR-700
  • L/R: KEF Q150 (Frequency Response 51Hz - 28 kHz, crossover @ 80Hz)
  • C: KEF Q250c (Frequency Response 68Hz - 28 kHz, crossover @ 80Hz)
  • Ceiling: KEF Ci200ER - Not measured in these graphs
  • Surround: SONY STR-7000 (Frequency Response 120Hz - 20 kHz, crossover @ 120Hz)


Thanks in advance!

174968

174969



174970
 

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1. There is no Ideal curve. It depends on your room and personal tastes. A gradual downward curve is common.

2. I think the “overlay” would be a house curve file. There are directions in the Help Files on how to make one.

3. Yes. If the deviations between the left and right speakers (red and green traces) are not audible, then there’s no reason to worry about it.

4. Turn down the volume on your receiver before taking the measurement. Pure sine wave tones are a demanding signal. No need to worry about getting an outboard amp unless you’re hearing clipping with program material on a regular basis.

Regards,
Wayne
 

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For the treble, put your speaker on a stand in the middle of your room and measure at 1m on the tweeter axis (and maybe also on the mid-axis between tweeter and bass for your non-coaxial speakers). Gate the measurement to remove room reflections (read the help for how), so you are looking at the direct sound FR that will reach your ears. This curve should be targeted to be fairly flat. Consider EQ, but be wary about any sharp dips (eg that might be crossover issues) as sometimes correction by EQ is not advisable.

For bass, below 200-250 Hz you can EQ the curves you posted without gating. Starting from 200 Hz, the target is a gradual rise to a few dB by 100 Hz, then flat below 100 Hz. Don’t try to boost with EQ where your speakers are ‘dying’ in the low bass. That’s the sub’s job. Speaking of which, measure the speaker and sub together, it can help with getting the levels and delays right at your 80 Hz XO. You can then EQ them together to get the target I described above.

For the gap between the two above frequency bands, it’s a bit tricky to do in-room at home, because you want to gate out the room but you can’t. Published anechoic data is valuable, and you could EQ for flat anechoic between 300-1000 Hz. Most speakers need little EQ here, or only something gentle. Ignore the measurements you took above, because you haven’t gated out the room.

Your Q3, yes it is normal, because you are picking up all the room reflections and it’s pretty wild stuff.
 
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