Nikkoholic
Active Member
Lots of threads about servo's but I'd like to post my findings today and see if anyone can chime on if this is normal or if you've had a similar experience.
A little history:
I've had my Beta's nearly a year. Like the sound but found the bass to be a bit overwehlming, and I like bass. I had to cut the bass on the servo about -6 to -9 db to get it to my liking.
So shared this with a few AKr's and recently another AKr experienced a similar situation on his newly acquired Gamma's. In the end when set up properly with the servo cables in place his "large" bass went away and he then he actually had to boost the bass to get it to his liking. So he called and challenged me to look over my system for proper connections. Well I was certain all was connected right. However he mentioned that when he had the servo "on" and pulled out the servo cable; the servo green light went off and then would reset just like when you turn it on. Mine didn't do that. I pull my servo cables in and out and no effect on the servo. Of course this is just with the servo on; not the entire system.
So checked my servo cables (which I think were remade due to lost cables from the prior owner). Pulled back the black cover and sure enough the 2 wires were indeed connected to the wrong pins on the 4 pin DIN connector. I verified this by pulling out the DIN female on the speaker and took the Servo top off and looked at the DIN connector inside and my cables were wired wrong. So even when my servo cables were connected; they really weren't.
So I fixed those this morning; after verifying it a million times, because I couldn't believe my eyes.
So went to hook everything back up and was anxious to hear the "real" IRS Betas. And got a Low Frequency feedback (line outs on my amp were down so brought them up slowly; no damaging sounds). So I checked, double checked and triple... all was right. Still oscillating / feedback. I thought this was the 60hz blast everyone describes. So I though maybe I have an inverting amp as infinity described (although it would be ullikely). So I switched to the "inverted phase" outputs on the servo. Then I got the classic 60Hz blast. Scary sound; but only for a split second. So I was convinced all external connections were correct.
So I spent the day tracing wires and making sure all was "in phase". Pulled all woofers out verified all wiring, verified accelarometer wiring.
Read some more in the Infinity literature and it Infinity mentions in the manual that even when everything is hooked up properly (which it was) you can experience a low frequency oscillation between 5 and 20 Hz. It sounds like turntable feedback to me. However this occurs even with all equipment off and just the servo and LF amp on. I have line output controls on my amp so I was able to "ease" into the range where the feedback started to experiment as to the causes. They state some amps have higher outputs and thus the Open Loop Feedback switch on the back of the servo can be switch to help eliminate this. So I lowered it to -6db and problem disappeared with no inputs on and now only showed up while music was playing (very dangerous) since it is unpredictable. So I switched it to -12db and that seems to have solved the problem. I played some songs with strong deep bass and all was fine. Bass does sound a little better with the servo working properly (assuming it is) however I now have to run my servo LF gain at +4 (on the front panel) to get good balance between the LF and HF towers.
This does make sense though, since previously I had to reduce the LF gain on the front of the servo by 6-9db and now running at +4-5 so about a 10-14db difference. Not sure why the -12db Open Gain Loop on the back reacts / eliminates the feedback vs. on the front controls.
Sorry for the lengthy comment. But I wanted to share the details in hopes of finding some other IRS owners that may have experienced similar Low Freq Oscillation / Feedback.
I know some other Beta owners who run much larger amps on the LF towers, I never understood that because my bass was too strong with both HF and LF amps the same output. Now I likely need more power on the low end or need to cut the line level controls on the HF tower to get a better balance.
SOOOO... can some IRS people chime in with their Open Loop Gain settings on the back. And is it there to eliminate the 5-20 Hz Oscillation that Infinity describes in the manual.
Thanks for reading and listening.
A little history:
I've had my Beta's nearly a year. Like the sound but found the bass to be a bit overwehlming, and I like bass. I had to cut the bass on the servo about -6 to -9 db to get it to my liking.
So shared this with a few AKr's and recently another AKr experienced a similar situation on his newly acquired Gamma's. In the end when set up properly with the servo cables in place his "large" bass went away and he then he actually had to boost the bass to get it to his liking. So he called and challenged me to look over my system for proper connections. Well I was certain all was connected right. However he mentioned that when he had the servo "on" and pulled out the servo cable; the servo green light went off and then would reset just like when you turn it on. Mine didn't do that. I pull my servo cables in and out and no effect on the servo. Of course this is just with the servo on; not the entire system.
So checked my servo cables (which I think were remade due to lost cables from the prior owner). Pulled back the black cover and sure enough the 2 wires were indeed connected to the wrong pins on the 4 pin DIN connector. I verified this by pulling out the DIN female on the speaker and took the Servo top off and looked at the DIN connector inside and my cables were wired wrong. So even when my servo cables were connected; they really weren't.
So I fixed those this morning; after verifying it a million times, because I couldn't believe my eyes.
So went to hook everything back up and was anxious to hear the "real" IRS Betas. And got a Low Frequency feedback (line outs on my amp were down so brought them up slowly; no damaging sounds). So I checked, double checked and triple... all was right. Still oscillating / feedback. I thought this was the 60hz blast everyone describes. So I though maybe I have an inverting amp as infinity described (although it would be ullikely). So I switched to the "inverted phase" outputs on the servo. Then I got the classic 60Hz blast. Scary sound; but only for a split second. So I was convinced all external connections were correct.
So I spent the day tracing wires and making sure all was "in phase". Pulled all woofers out verified all wiring, verified accelarometer wiring.
Read some more in the Infinity literature and it Infinity mentions in the manual that even when everything is hooked up properly (which it was) you can experience a low frequency oscillation between 5 and 20 Hz. It sounds like turntable feedback to me. However this occurs even with all equipment off and just the servo and LF amp on. I have line output controls on my amp so I was able to "ease" into the range where the feedback started to experiment as to the causes. They state some amps have higher outputs and thus the Open Loop Feedback switch on the back of the servo can be switch to help eliminate this. So I lowered it to -6db and problem disappeared with no inputs on and now only showed up while music was playing (very dangerous) since it is unpredictable. So I switched it to -12db and that seems to have solved the problem. I played some songs with strong deep bass and all was fine. Bass does sound a little better with the servo working properly (assuming it is) however I now have to run my servo LF gain at +4 (on the front panel) to get good balance between the LF and HF towers.
This does make sense though, since previously I had to reduce the LF gain on the front of the servo by 6-9db and now running at +4-5 so about a 10-14db difference. Not sure why the -12db Open Gain Loop on the back reacts / eliminates the feedback vs. on the front controls.
Sorry for the lengthy comment. But I wanted to share the details in hopes of finding some other IRS owners that may have experienced similar Low Freq Oscillation / Feedback.
I know some other Beta owners who run much larger amps on the LF towers, I never understood that because my bass was too strong with both HF and LF amps the same output. Now I likely need more power on the low end or need to cut the line level controls on the HF tower to get a better balance.
SOOOO... can some IRS people chime in with their Open Loop Gain settings on the back. And is it there to eliminate the 5-20 Hz Oscillation that Infinity describes in the manual.
Thanks for reading and listening.