Intro + Room EQ (BD-Design)

by Kristo, Thursday, February 27, 2020, 14:57 (97 days ago)
edited by Kristo, Thursday, February 27, 2020, 15:07

Hi all,

My name is kristo, and this is my first time here! I'm currently in the process of building out my sound system for two purposes: (a) for at home daily listening, and (b) for use in a small "party" like setting, where music is the focus and is used to provide an emotional experience over a night (as in, it's not just about dancing or feeling happy the whole time).

At the moment I own a set of Klipsch Cornwall IIs, but I will soon be purchasing a pair of Oris 150s and MiniDSP ICE125 (DSP + amp) for the low end. Initially, the Oris horns will be sitting on top of my Cornwalls and I will use the woofer in that enclosure with the Oris horn. Eventually I hope to expand to a 4 point system with custom bass horns. We'll see.

Anyways, right now I am taking my first stab at making my everyday listening room sound better. It currently feels bright/painful at higher volume levels and with more active music. I got a mic and REW, and here are my first measurements taken at listening position. I'm curious to know what y'all think.

SPL in the bass frequencies
[image]

SPL 20-20k Hz, 1/6th smooth
[image]

Waterfall 20-400hz, 0-500ms
[image]

Full Waterfall 0-300ms
[image]

Now, this is my first time interpreting these graphs and I have very little in terms of reference, but this is what I gather from them:

  • Significant room mode around 48hz - can be cured with my DSP when I get it?
  • Significant null at 100hz - also cured with DSP?
  • The frequency response 100hz+ seems generally ok?
  • I have significant issue with decay time at all frequencies, which is what I expected. I have concrete walls and floor/ceiling behind a layer of sheetrock. To fix this I should employ absorbers and diffusors on walls and ceiling, as well as a rug. Does that seem right?
    [/]

    So I think I have a long way to go... which is comforting because it confirms what my ears were telling me :yes: . Do you all see anything else I should notice from these?

    Also, here is a pic of the room so you can have some context:

    [image]

    Cheers,

    Kristo

Intro + Room EQ

by Bert @, Thursday, February 27, 2020, 15:26 (97 days ago) @ Kristo

Question: I assume that you ony did one measurement at the position the mic is on your salon table? And probably only the left speaker as well?

For measuring the room influences you should measure at your listening spot and listening height...

Try the other speaker as well...

BTW, the one 48Hz peak is responsible for the 96Hz dip...

Bert

--
BD-Design - Only the Best!

Intro + Room EQ

by Kristo, Thursday, February 27, 2020, 15:29 (97 days ago) @ Bert

Ah no I measured on a box in the black rocker chair next to the ficus, my normal listening position. Mic pointing directly between the speakers at listening height. And I measured using both L+R speakers. Should I do independently instead?

Also the SPL measurements are averages of 3 recordings

Intro + Room EQ

by Bert @, Thursday, February 27, 2020, 15:34 (97 days ago) @ Kristo

Should I do independently instead?

Better not... it will only confuse more!

The 48Hz peak can be reduced with DSP but that will not help the 96Hz dip. That dip is only there at your measuring spot... on your salon table it will probable look the opposite!

Boosting the dip with energy will not do anything anyhow... simply because it is the room doing that.

Bert

--
BD-Design - Only the Best!

Intro + Room EQ

by Kristo, Thursday, February 27, 2020, 15:39 (97 days ago) @ Bert

Interesting, when you said that the 96Hz dip is caused by the 48Hz peak, did you mean due to the frequencies interfering with each other? If so, then why would removing the 48Hz peak with DSP not also improve the 96Hz dip?

Also, regarding the waterfall diagrams, what do you suggest to clean up the decay? It seems pretty bad, do you agree?

Best

Kristo

Intro + Room EQ

by Bert @, Thursday, February 27, 2020, 19:23 (97 days ago) @ Kristo

Interesting, when you said that the 96Hz dip is caused by the 48Hz peak, did you mean due to the frequencies interfering with each other? If so, then why would removing the 48Hz peak with DSP not also improve the 96Hz dip?

If you would cure the 48Hz peak (acoustically) then the dip is gone as well...

If you DSP the peak out of the equation then the problem (standing wave) is still there but you give it less energy to work with. Same for the 96Hz... measure in the exact middle of the room and you'll see a peak at 96Hz and a dip at 48Hz.

You can also play a 48Hz or 96Hz sinus tone and walk around in the room. Do you really think that "curing" the problems at the listening spot cures the problem? What if are are lstening at the diner table with the same "cure?

Also, regarding the waterfall diagrams, what do you suggest to clean up the decay? It seems pretty bad, do you agree?

This does not have to be a major problem at first, a big carpet on the floor will help and curtains, plants.. but also moving the speaker a bit more out of the corner and a bit up (raised from the floor).

Bert

--
BD-Design - Only the Best!

Intro + Room EQ

by Kristo, Monday, March 02, 2020, 14:25 (93 days ago) @ Bert

If you DSP the peak out of the equation then the problem (standing wave) is still there but you give it less energy to work with. Same for the 96Hz... measure in the exact middle of the room and you'll see a peak at 96Hz and a dip at 48Hz.

Ah I see. After reading a bit more about standing waves I now have a better sense of what's happening. I also did try playing a sine wave at 48hz and walked around the room... indeed it was pretty dramatic.

It seems this is the first problem I should solve in my listening room then. I can move my speakers a bit away from the wall so they are not right in the high pressure area of the wave, and then I suppose my best bet will be applying some bass traps in the corners...

Alternatively I could build a second set of woofers to place behind me along the opposite wall. Would that solve the problem also?

Cheers,

Kristo

Intro + Room EQ

by Bert @, Monday, March 02, 2020, 15:07 (93 days ago) @ Kristo

Hi Kristo,

It seems this is the first problem I should solve in my listening room then. I can move my speakers a bit away from the wall so they are not right in the high pressure area of the wave, and then I suppose my best bet will be applying some bass traps in the corners...

Moving the speakers out of the corners will help in many ways...

Alternatively I could build a second set of woofers to place behind me along the opposite wall. Would that solve the problem also?


That will cure the first harmonic but introduce other problems at the same time..

A better trick to apply would be this:

http://www.bd-design.nl/forum/index.php?id=16140

Or built an open panel woofer system which will reduces such room problems too...

Bert

BTW, I still have those REL's in case you're interested...

Or suitable woofers which you can enclose in a DIY box and use one channel of your ICE125 to power and EQ those "EQ" boxes to tame the standing wave.

--
BD-Design - Only the Best!

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