Help with very strange subwoofer curve

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Hi I ha have just done my first analysis to set up my subwoofers (two) using REW and a minidsp 2x4 hd. However the curves I get are very strange compared to what I see online. I'm not sure how to intrepet them. If there is something wrong with the settings or if my subs are not good. I have 2 focal air subs in a small room. Thanks for the help.
 

Attachments

  • 20210406_133834.jpg
    20210406_133834.jpg
    253.4 KB · Views: 70

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
Make sure you don't have any crossover filters active in the miniDSP, a HP crossover filter might be in the path.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Thanks, I did deactivate them with the bypass filter and had that curve...so it must be something else...
 

Attachments

  • 16177137935167736240707341121668.jpg
    16177137935167736240707341121668.jpg
    276.2 KB · Views: 33

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
This is the full curve
 

Attachments

  • 16177141957556280193992944412622.jpg
    16177141957556280193992944412622.jpg
    287.4 KB · Views: 42

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
Try measuring very close (a few cm) to one of the subs with the other off to see what the sub's near field response looks like. The Focal Air is fairly small as subs go, so it won't go that far down. Spec does say -3 dB at 40 Hz though.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Thanks, I'll try that. So I should use the mic with the normal calibration file instead of the 90° and position the mic next to the subs instead of the listening position? Correct ?
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
Yes. The cal files should be the same at low frequencies anyway. Watch out for clipping, will need to test at a lower volume being so close.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Ok, thanks so much. Then, if I'm not taking the measures from the listening position. How would I calibrate for the delay of the subs being in different places in the room?
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
This is just to understand whether there is some problem affecting the response of the subs.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Still a similar curve putting the mic next to the speaker
 

Attachments

  • 16177210569704803686680514993209.jpg
    16177210569704803686680514993209.jpg
    281.9 KB · Views: 19

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Here is the whole curve
 

Attachments

  • 16177211171722857013430542214939.jpg
    16177211171722857013430542214939.jpg
    279.8 KB · Views: 32

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Where should I check that ? I'm using a Marantz 5014 avr and I set all speakers to small, crossover to 250hz, LFE only and 120hz
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Where should I check that ? I'm using a Marantz 5014 avr and I set all speakers to small, crossover to 250hz, LFE only and 120h
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
I the subwoofer I set the crossover to LFE setting (maximum) and volume to mid position (12 o'clock)
 

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
Try removing the miniDSP from the chain first to make sure that isn't having any effect. Could also try connecting the PC headphone output directly to a sub to see how it looks with nothing else in the path.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
If I connect the PC out directly to the sub, how is the pink noise reproduced ? Currently it is reproduced from the front left channel.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Hi John, I've tried taking the minidsp out of the chain and I still get a similar curve
 

Attachments

  • 20210410_115249.jpg
    20210410_115249.jpg
    240.6 KB · Views: 17

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
I've now tried setting the volume in the Subwoofer to max, and I think I get a better curve
 

Attachments

  • 16180492991423100203110472781121.jpg
    16180492991423100203110472781121.jpg
    281.7 KB · Views: 26

John Mulcahy

REW Author
Joined
Apr 3, 2017
Messages
7,212
It looks the same. Have you tried connecting the sub directly to the PC and measuring it that way?
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Yes, here you have the curves connected directly to the PC. In violet its connecting both rca inputs and below in green connecting only to LFE input.
 

Matt1980

Registered
Thread Starter
Joined
Oct 24, 2020
Messages
44
Yes, here you have the curves connected directly to the PC. In violet its connecting both rca inputs and below in green connecting only to LFE input.
 

Attachments

  • 16181336333087933106231345252239.jpg
    16181336333087933106231345252239.jpg
    283.5 KB · Views: 30
Top Bottom