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TOPIC: DDRC-22D killing the bass 60-100Hz

DDRC-22D killing the bass 60-100Hz 3 weeks 6 days ago #41530

  • Rullknufs
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Hey!

I got my DDRC-22D a couple of days ago and I have finally gotten around to testing it out. I first noticed that without any filters active there is a channel imbalance, right channel is louder than the left so the stereo image is shifted towards the left. With filters on that is corrected though and stereo image is centered.

The biggest problem however is that it kills my bass.



There you can see the channel imbalance and also the predicted response. I chose the room feel eq here in this pic but I also tried the Harman curve.

To confirm what I was hearing I did a measurement with REW.



The purple line is response without filters, both channels at the same time. Green line is with the Harman curve and the yellow is with the "Room feel" curve. Below 50Hz I get a good improvement but between 60-100Hz it totally kills the bass and it doesn't do much else in the rest of the frequency band either. I think I could probably get better results with my little 2x4 unit and REW eq.

Why does my DDRC-22D behave like this? The speakers are DIY floorstanders with 2x Morel CAW638 and a CAT408 in MTM configuration in a vented box. DAC is a NAD D1050 and amp is a S.A.T Amplifix.

Measurements were done with the UMIK-1 and a 90-degree calibration file and mic was pointed up towards the ceiling. The sofa (and sweet spot) is right next to the back wall.

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DDRC-22D killing the bass 60-100Hz 3 weeks 5 days ago #41543

Hi Rullknufs

I assume your REW measurements are done in the sweet spot only, right?

Dirac corrects the response "sort of averaged over the measurement positions". Try measuring approximately the same positions as measured with Dirac and use the average function in REW.

Best regards

PK
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DDRC-22D killing the bass 60-100Hz 2 weeks 5 days ago #41613

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Yes, the REW measurement was done only in sweetspot.

I had time today to do some new measurements. I began with trying out the "Chair" measurement preset in the Dirac software. Then I measured with/without Dirac in sweetspot and saw the same trend as before. Tried to do measurements in approximately the same positions in REW as in Dirac and did an average and ended up with this result. Green is with harman curve EQ in Dirac, averaged over 9 measurements at and around sweetspot. Red is sweetspot only but without Dirac.



All the measurements with Dirac had the same dip in the 60-100hz region. What is happening here that causes Dirac to go nuts? I mean, it seems to work perfectly fine below 50Hz and it seems to work for the mids as well.

I don't know if I shall bother experimenting any more with this now since I'll be moving to a house in 1.5-2 months time. Maybe it has something to do with my current room?

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DDRC-22D killing the bass 60-100Hz 2 weeks 17 hours ago #41701

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@Rullknufs

This is indeed very odd.. I wonder if it's something related to the measurement process. Few comments:
a) Please perform a measurement with the mic pointing at the speaker (not 90deg.)
b) You're making the 9 average measurements. Correct? How far away are you making the measurements?
c) I'm curious if it's worth to "not" boost the speaker outside their real performance. See how your natural response is diving at 30Hz on the blue measurement? That is what Dirac measured. You then applied a very heavy/tough target/boost to achieve with the target curve trying to get down to 20Hz. In room correction world, it's a big NO NO as you're basically trying to get your speakers to re-invent the laws of physics... Dirac can do some magic, but to some "extend". Per our experience, that 10dB boost is way too big.. Please move your target to follow the natural roll off of the speaker.
d) Please provide more information along with sharing your Dirac Live project. It would be telling to see what's behind the scenes here.
MiniDSP, building a DIY DSP community one board at a time.
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DDRC-22D killing the bass 60-100Hz 1 week 2 days ago #41803

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I finally had time today to do some more testing. Did new measurements with mic pointed at speakers. Also, got a shorter signal path now that I have bought a longer USB cable. Before it was Macbook Air -> Samsung smart tv via HDMI -> DDRC22. Now it's PC -> DDRC22 via optical cable.

The measurements for the sofa preset are taken across the whole sofa, which is approximately 2 meters wide. Height vaires maybe 50cm and depth maybe 50cm as well. For the chair preset (which I tried today) measurements are centered around the center of the sofa, with measurements taken around 30-40cm from sweetspot.

I tried today to move the window to just above 30Hz to avoid that boost. Didn't seem to help much.




Also, I don't know how to share my project since it says it is too large to be uploaded here. But maybe this google drive link works? drive.google.com/file/d/1K3f52YUWXQu8NJV...6jm/view?usp=sharing

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Last Edit: 1 week 2 days ago by Rullknufs.
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