USNRET Posted March 30, 2013 Share Posted March 30, 2013 I finally got all three front Belles configured alike with drivers, horns, crossovers, etc. I started setting the levels and noticed that the left has to be set about 4dB hotter than the other two to achieve equal output. Hummm, I know I need to check wiring but asuming that all wires had good connections and are in phase, what would cause this? After wiring checks I think I will swap amp channels and take a look at that (Emo XPA-5) Quote Link to comment Share on other sites More sharing options...
Schu Posted March 30, 2013 Share Posted March 30, 2013 4db's spunds like a lot... mine are within 1-1.5 of each other. Have you looked at the phase yet? My cornwalls WERE OOP Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted March 30, 2013 Share Posted March 30, 2013 Could also be the room. Both mine measure equal SPL with pink at the baffle and at the same voltage, but at the listening position the left channel consistently measures 1.5 dB low. Quote Link to comment Share on other sites More sharing options...
garyrc Posted March 30, 2013 Share Posted March 30, 2013 Could also be the room. Yes, could be. What kind of signal are you using to balance? I think there is no ideal choice. Many use band limited pink noise, e.g., 500 - 2K. Others use music. Don't use a single tone. Don't use bass because the position in the room can make a big difference. Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 30, 2013 Share Posted March 30, 2013 I started setting the levels and noticed that the left has to be set about 4dB hotter than the other two to achieve equal output. Hummm, ...what would cause this?A picture of your room might help. I've also found that being off-axis in measurement position (microphone) can make a 1 dB difference, easy. If the room and room placement happens to also decrease the SPL from that side, I can understand 4 dB difference. Are you averaging more than one microphone position? Chris Quote Link to comment Share on other sites More sharing options...
philipbarrett Posted March 31, 2013 Share Posted March 31, 2013 Swap the wiring starting from the source through to the connections into the power amp. If the problem moves to the right channel you have a problem with the source to amp chain, if it doesn't you have a problem post amplifier. Quote Link to comment Share on other sites More sharing options...
USNRET Posted April 1, 2013 Author Share Posted April 1, 2013 Edit: no test tonight; all kiddos down with the stomach bug so no 'loud noises'. I will investigate further tonight. I am using an analog RS meter mounted at ear level on a tripod at one location. Onkyo PR-SC5507 pre/pro self generated tone (noise). I set volume to achieve 85 dB at the SPL meter with 0 correction to the center speaker and then set left and right to match. I will jot down the numbers tonight and try to get a better picture of the room assuming that trying the suggested remedies does not reveal the problem. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted April 2, 2013 Share Posted April 2, 2013 You could do a nearfield test to eliminate the room as an issue also. Wouldn't have to be loud. Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted April 2, 2013 Share Posted April 2, 2013 I will jot down the numbers tonight If you can also sample the AC voltage across each channel while your measuring respective SPL, the numbers would prove even more insightful. Not mission critical, just a better snapshot of whats going on. Quote Link to comment Share on other sites More sharing options...
USNRET Posted April 2, 2013 Author Share Posted April 2, 2013 sample the AC voltage across each channelAt crossover input from amp using True RMS DVM at the reference level volume (or any volume as long as the amplitude and frequency 'should be' equal to the other speakers measured?) Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted April 2, 2013 Share Posted April 2, 2013 At crossover input from amp using True RMS DVM at the reference level volume ^^^This ..at the crossover input or at the amp terminals. Which ever spot proves more convenient for measurement at the time. Quote Link to comment Share on other sites More sharing options...
USNRET Posted April 2, 2013 Author Share Posted April 2, 2013 Voltage measuring will have to wait but here is some info. Analog RS meter "C" weighted and slow using pre/pro built in test. Meter on coffee table (mic up) at a height between top of bass bin and bottom of squawker. L & R slightly toed in but left more so (make my couch comfy spot better in 2 channel). As you can see I was off in my first post's levels (old memory cells). Speaker: L C R Distance: 89" 72" 93" Meter at 82dB -9.0 -12.0 -6.5 I will next swap L&R Pre > Amp cables, re-measure and if nothing proven proceed with the voltage checks. Later Quote Link to comment Share on other sites More sharing options...
Dr Morbius Posted April 10, 2013 Share Posted April 10, 2013 Did you do the swap? How did it turn out? Quote Link to comment Share on other sites More sharing options...
USNRET Posted April 20, 2013 Author Share Posted April 20, 2013 This took a little bit before I stumbled across the error of my ways. I still don't know WHY this would cause the issued but......... After measuring, swapping cables, etc with inconclusive results I found that somehow my pre/pro had an in-correct setting. The fronts were set to "Bi-Amp". Changing this to the correct setting resolved the issue. Only minor PIA is that I found that this pre/pro doesn't let you change the tone volume with the master volume knob so with my speakers I have to set the center at -12 which is the minimum and adjust the others to it to get 85 dB at the couch. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted April 20, 2013 Share Posted April 20, 2013 Why not set the speakers to be 75 db at the listening position. This is the standard setting for HT. The accurracy of the setting is in question when speakers are setup at the extreme of the calibration program. What is the max/min. speaker settings for the calibration program? Quote Link to comment Share on other sites More sharing options...
Arkytype Posted April 23, 2013 Share Posted April 23, 2013 I've found that setting my center Belle 6 dB lower (using SPL meter at listening position) than the combined output of my two flanking Klipschorns is just about right. If you have a helper, try sitting at the sweet spot and while listening to a well-recorded vocal (e.g. James Taylor), have helper raise the volume of the center Belle until it is just noticeable. Shift your listening position left and right of center and note that the vocal image seems to stay more centered than with the center Belle off. You will probably discover that raising the center Belle level to match each of the flanking loudspeakers (i.e. 85 dBL 85 dBC 85 dBR) is too much center fill. Lee Quote Link to comment Share on other sites More sharing options...
Mongo171 Posted April 23, 2013 Share Posted April 23, 2013 I've found that setting my center Belle 6 dB lower (using SPL meter at listening position) than the combined output of my two flanking Klipschorns is just about right. That's because at the main LP, the center speaker is probably a shorter distance to you than the mains (assuming that the mains are equidistant from the center). In my setup, all 4 speakers are at different distances to the main LP. I set the center to 75db at 0 trim. Then I set the rest of the speakers accordingly. You also have to account for sensitivity of the speakers. USNRET doesn't have that problem since his LCR are the same. Quote Link to comment Share on other sites More sharing options...
garyrc Posted April 23, 2013 Share Posted April 23, 2013 My Belle Klipsch center is set at the same SPL as each of my flanking Klipschorns, but the signals are being sent through an AV preamp that adjusts for the fact that the Belle is closer to the sweet spot seat (automatic time/distance adjustment in the pre-pro). It sounds just right for movies and many music CDs/SACDs, etc., BUT it is not right for some music disks. I think it depends on the kind of microphone placement the recordists were using. Before I had an AV pre-pro the Belle needed to be softer, which is consistant with the wide stage stereo articles in the Klipsch Audio Papers, written decades before AV pre-pros. Quote Link to comment Share on other sites More sharing options...
USNRET Posted April 23, 2013 Author Share Posted April 23, 2013 Note: I only use the front three in HT 5.1 mode while using the same L&R with a completely different, discrete 2 channel rig. The center is not active in 2 channel even though I win a few bets with folks believing the center is playing. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted April 23, 2013 Share Posted April 23, 2013 A phantom center can be really effective when setup right Quote Link to comment Share on other sites More sharing options...
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