Dayton UM 18-22 clipping issue with sealed cabs and crown amps.

[moves]

I'd set gain to where it barely clipped at full output (e.g. the loudest you'll listen at, I use reference level), and I'd leave sensitivity at 1.4V unless I actually needed to move it to .775V. Pre-out level varies with pre-amp but looked back at your first post to get an answer, a Pioneer avr which likely has sufficient pre-out level for 1.4V setting in any case.

Reference level i.e. 0 db on the AVR? I never listen that loud... I'll look into the sensitivity but I did look into it last Feb and

 

[moves]

I looked back on my emails and this is what Crown said:

At .775V it will be louder.
Input sensitivity is the amount of voltage RMS it takes to drive the amplifier to peak output, so the lower the number the quicker it gets louder.
The .775V setting is for cases where the output of the device sending the signal to the amplifier doesn’t have anymore headroom, the disadvantage of this is it’s more noisy than the higher setting.

It’s safe as long as you don’t overdrive the input and clip the amp.

 

[moves]

I'd set gain to where it barely clipped at full output (e.g. the loudest you'll listen at, I use reference level), and I'd leave sensitivity at 1.4V unless I actually needed to move it to .775V. Pre-out level varies with pre-amp but looked back at your first post to get an answer, a Pioneer avr which likely has sufficient pre-out level for 1.4V setting in any case.

I looked to see when the need for .775V should be set but I couldn't find any info on it. What does your AVR have to output in order to be considered too low for 1.4V on the crown?

My PIONEER is as follows:

Audio Section
Input (Sensitivity/Impedance)
PHONOMM.......................... 4.2mV/47kΩ
LINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 mV/47 kΩ

Output (Level/Impedance)
REC ................................ 335mV/2.2kΩ
Signal-to-Noise Ratio (IHF, short circuited, A network)
LINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 dB
Signal-to-Noise Ratio [EIA, at 1 W (1 kHz)]
LINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 dB

 

[lovinthehd]

I looked to see when the need for .775V should be set but I couldn't find any info on it. What does your AVR have to output in order to be considered too low for 1.4V on the crown?

My PIONEER is as follows:

Audio Section
Input (Sensitivity/Impedance)
PHONOMM.......................... 4.2mV/47kΩ
LINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335 mV/47 kΩ

Output (Level/Impedance)
REC ................................ 335mV/2.2kΩ
Signal-to-Noise Ratio (IHF, short circuited, A network)
LINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 dB
Signal-to-Noise Ratio [EIA, at 1 W (1 kHz)]
LINE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 dB

Well those aren't the specs regarding your pre-out voltage, which Pioneer avr model do you have? Many avrs only list a nominal output level (often they just show 1.0 or 1.2 V but that isn't the max output they're capable of.....but less than 1.4V would be when you use .775V. You're clipping so early it just seems your signal is too hot, so either dial back the gain on the amp and/or change the sensitivity level on the amp.

ps What is the setting for your sub level in the avr set at?

 

[moves]

Well those aren't the specs regarding your pre-out voltage, which Pioneer avr model do you have? Many avrs only list a nominal output level (often they just show 1.0 or 1.2 V but that isn't the max output they're capable of.....but less than 1.4V would be when you use .775V. You're clipping so early it just seems your signal is too hot, so either dial back the gain on the amp and/or change the sensitivity level on the amp.

ps What is the setting for your sub level in the avr set at?

I have the Pioneer SC 27 Elite....

I am assuming that setting the Crown to 1.4V would be safer? it is obviously less bass heavy on 1.4V. I think Crown said there is about 5.4 db difference in the two settings. I turned the gain up 2 notches and it seems to sound good.

In the minidsp... should there be any boost at all? I am pretty sure I have +5 db boost on the input 1 coming from the AVR on the minidsp... that doesn't seem right.

 

[Irvrobinson]

I have the UMIK that I can use to test the sound level but I haven't tested it when clipping. The room is quote large... LWH = 30 X 13 X 7 feet.

30x13x7 feet is not large by subwoofer standards, especially for a pair of 18" subs, even sealed ones. That's only 2730 cubic feet, which falls into AH's "Medium" sized room category. The Extreme rating would be for a room about twice the volume of yours or greater (>5000 cubic feet).

So I'm smelling something fishy. Your observation of amp clipping and two 18" sealed subs driven by 1500 watts each can't handle a 2730 cubic foot room just doesn't make sense.

 

[lovinthehd]

I have the Pioneer SC 27 Elite....

I am assuming that setting the Crown to 1.4V would be safer? it is obviously less bass heavy on 1.4V. I think Crown said there is about 5.4 db difference in the two settings. I turned the gain up 2 notches and it seems to sound good.

In the minidsp... should there be any boost at all? I am pretty sure I have +5 db boost on the input 1 coming from the AVR on the minidsp... that doesn't seem right.

Yes, moving it to 1.4V should be safer in that it will be harder to clip, same for the gain adjustment (i.e. turning it down)....did you already change it and then turned the gain up after? I don't know what you did in the minidsp, but it has voltage output limit of 2.0V for unbalanced outputs (rca) according to the info for the 2x4HD, but if you're boosting/eq'g with it it will have an effect. I don't see in your avr manual any pre-out spec particularly. You might check this thread, maybe its been discussed/measured. Do you use MCACC at all?

 

[moves]

Yes, moving it to 1.4V should be safer in that it will be harder to clip, same for the gain adjustment (i.e. turning it down)....did you already change it and then turned the gain up after? I don't know what you did in the minidsp, but it has voltage output limit of 2.0V for unbalanced outputs (rca) according to the info for the 2x4HD, but if you're boosting/eq'g with it it will have an effect. I don't see in your avr manual any pre-out spec particularly. You might check this thread, maybe its been discussed/measured. Do you use MCACC at all?

Yes I switched it to 1.4 and turned the gain up two notches because there wasn't enough bass. I use mcacc with the 7.0 speakers but not with the sub. After the AVR calibrates, I enable the subwoofer so the mcacc doesn't calibrate it. I will check the thread you linked tomorrow. Thanks for your input though I appreciate all the help.

 

[lovinthehd]

Not sure what you mean by there wasn't enough bass....are you still clipping at low volume levels?

You might try having the avr adjust the sub level via MCACC....and having it eq and match to your mains isn't a bad thing necessarily (altho MCACC of that age didn't correct very low frequencies on subs, think it stops at 31hz).

 

[moves]

Not sure what you mean by there wasn't enough bass....are you still clipping at low volume levels?

You might try having the avr adjust the sub level via MCACC....and having it eq and match to your mains isn't a bad thing necessarily (altho MCACC of that age didn't correct very low frequencies on subs, think it stops at 31hz).

When I switched it from .775 to 1.4 the amount of bass wasn't strong enough to my liking so I turned the gain up two notches and it sounds good. I haven't had it clip but even on .775 it was only clipping once in a blue moon.