jcmusic Posted March 15, 2014 Share Posted March 15, 2014 Here are some measurements of my room, feel free to offer advice if you know something that could help. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 15, 2014 Author Share Posted March 15, 2014 Here are a few more with the subs... Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 15, 2014 Author Share Posted March 15, 2014 (edited) In the curve with the eq and subs the subs are crossed at 80hz and a HPF at 80hz is on the mains. It sounds good here but the curve looks ugly from 75hz to 50hz. Edited March 15, 2014 by canyonman Quote Link to comment Share on other sites More sharing options...
garyrc Posted March 15, 2014 Share Posted March 15, 2014 (edited) Mic position in room, including location of speakers, type, walls, etc.? Speakers in phase? Is that 1/3 octave smoothing, or more, or less? Seems to be some bass cancellation when both speakers are on (RE: post #1) ... looks pretty good with sub in later posts. Still don't know why there is attenuation when front two speakers are on (no sub), as opposed to with either one on alone. REW? Edited March 15, 2014 by Garyrc Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 15, 2014 Author Share Posted March 15, 2014 The mic position is in the LP at tweeter level, khorns, sheetrock covered with paneling. Speaker phase yes, 1/12 smoothing.. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted March 15, 2014 Share Posted March 15, 2014 If you can keep your entire system inside a plus/minus 5 db envelope in a real room (which you are doing), this is a good thing. Try an RTA with Pink noise and you will see a much more realistic picture of your sound. 1 Quote Link to comment Share on other sites More sharing options...
garyrc Posted March 15, 2014 Share Posted March 15, 2014 The mic position is in the LP at tweeter level, khorns, sheetrock covered with paneling. Speaker phase yes, 1/12 smoothing.. Looking better with eq & subs. The dip in Khorns (alone) at around 70 Hz + shows up in some of PWK's curves (in a real room, not an anechoic chamber ... don't know about those in chamber), and in some of mine. What EQ do you use? Khorn alone peak 30 to 45 looks solid. Better a peak there than a dip, balance-wise, IMO. All in all, pretty good! Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 15, 2014 Share Posted March 15, 2014 Could you label each picture with the configuration for the measurement? What speakers are playing, any processing, mic position, etc... That dip at 80Hz should be fixed...and we can see some voicing issues up top too. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 15, 2014 Author Share Posted March 15, 2014 The mic position is in the LP at tweeter level, khorns, sheetrock covered with paneling. Speaker phase yes, 1/12 smoothing.. Looking better with eq & subs. The dip in Khorns (alone) at around 70 Hz + shows up in some of PWK's curves (in a real room, not an anechoic chamber ... don't know about those in chamber), and in some of mine. What EQ do you use? Khorn alone peak 30 to 45 looks solid. Better a peak there than a dip, balance-wise, IMO. All in all, pretty good! I am using two Yamaha YDP 2006 parametric Eq's. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 15, 2014 Author Share Posted March 15, 2014 Could you label each picture with the configuration for the measurement? What speakers are playing, any processing, mic position, etc... That dip at 80Hz should be fixed...and we can see some voicing issues up top too. I did if you click on the pic and look at the bottom left of the pic you will see it, the first three are all flat. The ones with the subs are flat also, with the subs crossed at 80hz. The last pic that says Eq with subs is where I have pulled down the peaks and am using a HPF at 80hz on the mains and the subs crossed at 80hz. These are khorns with a 2 wpc amp... Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 16, 2014 Share Posted March 16, 2014 (edited) The graphs with "both speakers" look like combs in your woofer frequencies. Look into comb filters. What are the exact dimensions of your room including ceiling height? Edited March 16, 2014 by mustang guy Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 16, 2014 Author Share Posted March 16, 2014 The graphs with "both speakers" look like combs in your woofer frequencies. Look into comb filters. What are the exact dimensions of your room including ceiling height? My room is 16X13.5X8 Quote Link to comment Share on other sites More sharing options...
Effster Posted March 16, 2014 Share Posted March 16, 2014 What great timing! I just started doing this myself last weekend.Im using a Rane DEQ-60 to make adjustments.This was my first pass at it,I am going to try and find some time tomorrow to tune it some more.It is alittle light in the bass department,so I think I need to curve the bass end up some.Both of these attachments are 1/3 octave smoothed.Any and all comments welcomed as this is another learning curve.Jeff Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 16, 2014 Share Posted March 16, 2014 (edited) The graphs with "both speakers" look like combs in your woofer frequencies. Look into comb filters. What are the exact dimensions of your room including ceiling height? My room is 16X13.5X8 First of all, the height and length of your room may be causing you problems. It gives you an axial resonance overlap at ~70 and ~140 Hz. When one dimension is exactly double another it causes resonance issues. Your room is 16' long, which is exactly twice the ceiling height 8'. This is a tough nut to crack. It is the room you have. If the room were 16'6, or the ceiling 7'8, there wouldn't be a problem. Next. When you compare the left by itself and the right by itself in the graphs above, they are quite different. Make sure the microphone is exactly 1 meter from the speaker and do another reading. Those speakers need to be the same before you proceed. If they aren't, you may as well stop until you figure out why. They should be close to exacly alike. Once that is done, walk around with an RTA while playing pink noise, and watch the different frequencies raise and lower as you walk through your room modes. That is your enemy. You cannot get rid of them. What you can do is make a sweet spot for listening. Any other seat will be inferior. That doesn't mean bad, but it does mean not as good as the sweet spot.Since you have Khorns, this may mean moving your chair, or perhaps putting the horns in different corners. If you had Audyssey, this would be done automatically for you, and better than you could do yourself, as it will change the EQ and timing to minimize room modes in measured seating positions. That's tough to do manually. You get those front speakers right, and don't worry about the subs for now. Edited March 16, 2014 by mustang guy Quote Link to comment Share on other sites More sharing options...
garyrc Posted March 16, 2014 Share Posted March 16, 2014 (edited) What great timing! I just started doing this myself last weekend.Im using a Rane DEQ-60 to make adjustments.This was my first pass at it,I am going to try and find some time tomorrow to tune it some more.It is alittle light in the bass department,so I think I need to curve the bass end up some.Both of these attachments are 1/3 octave smoothed.Any and all comments welcomed as this is another learning curve. Jeff before.jpg after.jpg Is this with your '78 K-horns and your sub? You could turn the sub up a little?? At what frequency is the sub cutting in? Do you have your K-horns going all the way down, with a separate low pass filter on the sub, or do you have a true crossover to the sub at a certain frequency? The "after" curve looks really good, but it's a little hard to tell because you have 10 dB divisions up the side, and 5 dB ones are conventional, so your curve may appear to be a little more smooth than it would with 5 dB divisions. Also, can you adjust things so your graph goes all the way from 20 to 20K? The "before" graph has the low bass cut off, and the "after" ends before you get to the high treble. Edited March 16, 2014 by Garyrc Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 16, 2014 Author Share Posted March 16, 2014 Next. When you compare the left by itself and the right by itself in the graphs above, they are quite different. Make sure the microphone is exactly 1 meter from the speaker and do another reading. Those speakers need to be the same before you proceed. If they aren't, you may as well stop until you figure out why. They should be close to exacly alike. MG, Thanks for your advice the measurements were taken with the mic at the LP, so I am thinking the room is creating the difference in the two speakers. Also the room is 16.5X13.4X8 if that makes a difference. I am also thinking of just running the subs full range and using the EQ's to adjust the subs and the mains to see if I can improve things... Quote Link to comment Share on other sites More sharing options...
Don Richard Posted March 16, 2014 Share Posted March 16, 2014 You can use windowing to remove some of the room effects and get the true response of the speaker if you are not already doing that. It is good to run phase plots along with the frequency response plots. Frequency response plots alone don't give the complete picture of what's going on. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 16, 2014 Share Posted March 16, 2014 (edited) Next. When you compare the left by itself and the right by itself in the graphs above, they are quite different. Make sure the microphone is exactly 1 meter from the speaker and do another reading. Those speakers need to be the same before you proceed. If they aren't, you may as well stop until you figure out why. They should be close to exacly alike. MG, Thanks for your advice the measurements were taken with the mic at the LP, so I am thinking the room is creating the difference in the two speakers. Also the room is 16.5X13.4X8 if that makes a difference. I am also thinking of just running the subs full range and using the EQ's to adjust the subs and the mains to see if I can improve things... Running the subs full range is a mistake, IMHO. Have you tested each speaker individually recently? You are assuming it is the room is causing the effects, and that may be true. Don is making the point that I made earlier when I mentioned a comb filter. That is what looks like is going on in your graph with both khorns. On page 18 of your Yamaha 2006 manual it discusses [delay]. Using delay on one speaker only, you are adjusting your phase of a pair. You have the ability here to destroy the comb filtering and deal with your room modes. That is what Audyssey would do. Once that is done, you can work on the EQ. Once the mains are right, you can turn your subs on at 50 and do the rest. Edited March 16, 2014 by mustang guy Quote Link to comment Share on other sites More sharing options...
jcmusic Posted March 16, 2014 Author Share Posted March 16, 2014 I have no idea how to use the delay properly, I see it is simple to function but; I don't know the math or what to look for... Quote Link to comment Share on other sites More sharing options...
mustang guy Posted March 16, 2014 Share Posted March 16, 2014 ... Also the room is 16.5X13.4X8 if that makes a difference. ... Yes it does. Quote Link to comment Share on other sites More sharing options...
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