Need help with louder left channel
I had another thread on this with my TT but it seems there's more going on, could even be user error...dunno.
My listening room isn't the most ideal for SDA's but it works for the most part, just under the minimums as far as width goes. Being in the sweet spot, I focus my attention to the left slightly. Some vocals are centered but the majority of playback is biased to the left.
My equipment in question is:
Technics 1200 Mk5 / Phonomena 2
Denon 2910
Yamaha CX-1000 Preamp
B&K ST-202
SDA-2B TL'd & over 500 hours on new Sonicaps
AQ Crystal 10'
I know room dimensions play a part but this is more pronounced
I originally started with my sound meter on the TT and I had about a 1.5db gain on the left. I measured just in front of the cloth in the center on both speakers and the left was always higher using the HiFi news test LP. I swapped cables everywhere and the end result was always a bias to the left.
I downloaded a few mono test tones and this time used the CD player, took more measurements on a tripod from 1' away and from 3' away. In some cases the speakers were close in db's but not all the time.
All values are 100Hz, 250Hz, 440Hz, 1kHz
L speaker: 81, 82.5, 84, 79
R speaker: 80, 82.5, 84.5, 74
Too close to call except the 1kHz tone which was substantial.
When I moved in to 1':
L speaker: 92, 90.5, 92, 87
R speaker: 91, 89.5, 92, 88
The 91 db value on the right was probably 90.7-90.8, was just under the 91 mark.
I believe I need to start from scratch and perform these tests a different way. Could be something very simple or I may need a component change, the age of the CX-1000 has me concerned. I measured the CD tones with the IC cable removed as well as the test LP.
I have a DMM with logging capability and an old Tek 465B scope that I don't know how to use very well...:cheesygrin: may not even make a difference in determining what my problems are but are avail if needed. If you need more precise measurements I can probably get them for you, I'm open to all suggestions.
My listening room isn't the most ideal for SDA's but it works for the most part, just under the minimums as far as width goes. Being in the sweet spot, I focus my attention to the left slightly. Some vocals are centered but the majority of playback is biased to the left.
My equipment in question is:
Technics 1200 Mk5 / Phonomena 2
Denon 2910
Yamaha CX-1000 Preamp
B&K ST-202
SDA-2B TL'd & over 500 hours on new Sonicaps
AQ Crystal 10'
I know room dimensions play a part but this is more pronounced
I originally started with my sound meter on the TT and I had about a 1.5db gain on the left. I measured just in front of the cloth in the center on both speakers and the left was always higher using the HiFi news test LP. I swapped cables everywhere and the end result was always a bias to the left.
I downloaded a few mono test tones and this time used the CD player, took more measurements on a tripod from 1' away and from 3' away. In some cases the speakers were close in db's but not all the time.
All values are 100Hz, 250Hz, 440Hz, 1kHz
L speaker: 81, 82.5, 84, 79
R speaker: 80, 82.5, 84.5, 74
Too close to call except the 1kHz tone which was substantial.
When I moved in to 1':
L speaker: 92, 90.5, 92, 87
R speaker: 91, 89.5, 92, 88
The 91 db value on the right was probably 90.7-90.8, was just under the 91 mark.
I believe I need to start from scratch and perform these tests a different way. Could be something very simple or I may need a component change, the age of the CX-1000 has me concerned. I measured the CD tones with the IC cable removed as well as the test LP.
I have a DMM with logging capability and an old Tek 465B scope that I don't know how to use very well...:cheesygrin: may not even make a difference in determining what my problems are but are avail if needed. If you need more precise measurements I can probably get them for you, I'm open to all suggestions.
Post edited by gmcman on
Comments
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switch the speaker cables and see if the "weak" channel follows or stays with the left channel. If it follows the speaker you know where the problem resides. If not then check the output of both the amp, and the pre-amp with a volt ohm meter. You didn't mention what sort of sound pressure meter you are using but some of them are notoriously inaccurate. You are much better off with the VOM. This is one of those areas where an audio signal generator (ASG)is so handy to have, I have a couple the one I mostly use is a nice TS-382F/U (1958) made by Telectro Industry Inc. which I picked up 10 years ago for $10 dollars. With it you can inject a frequency of your choice at what ever input level you want. With an ASG you can quickly track down these kinds of problems.
By the way have you done these measurements with the SDA interconnect cable disconnected?Radio Station W7ITC
