Anyone know of a way to reduce the level of the signal from the main L and R outputs whilst maintaining the main fader at or about unity level? Have the console in a local theatre where the amps are normally run with the gains fully open but this only allows me to raise the main fader to about -50 before reaching the required audio level in the auditorium. To reach a situation where I can work with the main output fader at unity level I have had to turn the amp gains down by about 60%. If there was a way to attenuate the output level at the desk without having to adjust the house P.A. amps that would be most helpful. Any suggestions?
Midas M32 Output Level
- Thread starter Bob Main
- Start date
Re: Midas M32 Output Level
The better way is what you have done, turn the amp attenuation down. This gives better signal to noise ratio.
The better way is what you have done, turn the amp attenuation down. This gives better signal to noise ratio.
Re: Midas M32 Output Level
50dB is quite a bit of gain reduction. Are you sure you're connected to a line level input and not a mic level input on the house system?
50dB is quite a bit of gain reduction. Are you sure you're connected to a line level input and not a mic level input on the house system?
Re: Midas M32 Output Level
That caught my eye, too. 50dB is a significant amount of gain. The frequent problem when going from analog to digital mixing is understanding the difference between 0 dBvu is NOT 0 DBFS. Folks that use the old analog trim method of "PFL the input, turn up the trim until the signal hits "0" on the meter" are adding about 20dB of gain if they do this hitting 0 DBFS (and making for some bad sound if the signal gets louder).
That caught my eye, too. 50dB is a significant amount of gain. The frequent problem when going from analog to digital mixing is understanding the difference between 0 dBvu is NOT 0 DBFS. Folks that use the old analog trim method of "PFL the input, turn up the trim until the signal hits "0" on the meter" are adding about 20dB of gain if they do this hitting 0 DBFS (and making for some bad sound if the signal gets louder).
Re: Midas M32 Output Level
To answer your question, you can run everything through a DCA and then adjust the level of the DCA to whatever level you need be at unity for your amps.
Art
To answer your question, you can run everything through a DCA and then adjust the level of the DCA to whatever level you need be at unity for your amps.
Art
Re: Midas M32 Output Level
Hi Guys
Many thanks for your responses to date. House amps are Yamaha XP3500's and as I previously indicated are normally run with the gains fully open. I have worked in this particular theatre on and off for about 10 years, firstly with a Yamaha DM1000 and latterly with a Presonus 24.4.2 and have always just hooked the desks up to the main house L and R returns, ran the respective main output fader at unity level and achieved an ideal sound pressure level in the auditorium. (Amps are installed in a remote room and never before have I had to make any adjustment to them. House techs confirm that the gains have not been altered since my last visit so all should be "as normal").
Today I go in with the new M32, set the individual channel input trims to hit about -6 on the meter and start to push up the main output fader and hey presto we get the normal sound pressure level when the main fader reaches the -50 mark!
I know that the house amps do have an adjustable input sensitivity but as I have already indicated, it has never been necessary for me to even consider adjusting them in the past so I can only conclude that he M32 outputs a far hotter signal level than either of my previous desks. What I'm basically looking for is some form of digital trim equivalent to the output pot that exists on the main outputs of the Presonus. Any further thoughts or suggestions would be welcome. Meanwhile I'm just working away with the gains on the Yamaha amps reduced by 60%.
Hi Guys
Many thanks for your responses to date. House amps are Yamaha XP3500's and as I previously indicated are normally run with the gains fully open. I have worked in this particular theatre on and off for about 10 years, firstly with a Yamaha DM1000 and latterly with a Presonus 24.4.2 and have always just hooked the desks up to the main house L and R returns, ran the respective main output fader at unity level and achieved an ideal sound pressure level in the auditorium. (Amps are installed in a remote room and never before have I had to make any adjustment to them. House techs confirm that the gains have not been altered since my last visit so all should be "as normal").
Today I go in with the new M32, set the individual channel input trims to hit about -6 on the meter and start to push up the main output fader and hey presto we get the normal sound pressure level when the main fader reaches the -50 mark!
I know that the house amps do have an adjustable input sensitivity but as I have already indicated, it has never been necessary for me to even consider adjusting them in the past so I can only conclude that he M32 outputs a far hotter signal level than either of my previous desks. What I'm basically looking for is some form of digital trim equivalent to the output pot that exists on the main outputs of the Presonus. Any further thoughts or suggestions would be welcome. Meanwhile I'm just working away with the gains on the Yamaha amps reduced by 60%.
Re: Midas M32 Output Level
The studiolive has a max output of +24dBu while the m32 'only' have +21dBu, so the m32 is overpowered by the studiolive.
This indicates that the level control at the back of your studiolive is turned down quite a lot.
The studiolive has a max output of +24dBu while the m32 'only' have +21dBu, so the m32 is overpowered by the studiolive.
This indicates that the level control at the back of your studiolive is turned down quite a lot.
Re: Midas M32 Output Level
Hi Robert
On the contrary, I always had the level control pot on the Presonus set at about 80% of its range. I was aware from checking the manual that the maximum output of the M32 was slightly lower than that of the Presonus but had thought that 100% of the M32 output would equate (roughly) to 80% of the maximum Presonus output. However, I certainly never expected to only reach a fraction of the main fader travel on the M32 before achieving the same s.p.l. In the auditorium.
Hi Robert
On the contrary, I always had the level control pot on the Presonus set at about 80% of its range. I was aware from checking the manual that the maximum output of the M32 was slightly lower than that of the Presonus but had thought that 100% of the M32 output would equate (roughly) to 80% of the maximum Presonus output. However, I certainly never expected to only reach a fraction of the main fader travel on the M32 before achieving the same s.p.l. In the auditorium.
Re: Midas M32 Output Level
Tim
Thanks for your comment and observation regarding the trim levels perhaps being set too high. The -6 that I mentioned is the figure achieved on the individual channel meters - the figures go -60, -30 (green l.e.d.'s) -18, -12, -6 (yellow l.e.d.'s) and then then Clip (red l.e.d.). Given your observation about -6 being too hot where would you recommend the input levels should be set at?
Regards.
Tim
Thanks for your comment and observation regarding the trim levels perhaps being set too high. The -6 that I mentioned is the figure achieved on the individual channel meters - the figures go -60, -30 (green l.e.d.'s) -18, -12, -6 (yellow l.e.d.'s) and then then Clip (red l.e.d.). Given your observation about -6 being too hot where would you recommend the input levels should be set at?
Regards.
Re: Midas M32 Output Level
-30 steady on, -18 occasional flash. Loud stuff, maybe tick the -12.
-30 steady on, -18 occasional flash. Loud stuff, maybe tick the -12.
Re: Midas M32 Output Level
Yes, absolutely.
You are setting your input trims much higher in comparison to what you were doing with your other consoles. Definitely cut at least 12 to 18 dB out right there and you will probably come up with a considerably more functional mix.
Of course, if you want to keep doing it the way you are currently doing it, the idea of sending the master L&R to the Matrix and throttling it back there to whatever output level you want is a fine idea too.
Either method will work fine, but by dialing back the input sensitivity (input trims) you can get more "headroom" on that input for unexpected louder noises. Personally, I don't think 6dB is enough headroom to have.
Yes, absolutely.
You are setting your input trims much higher in comparison to what you were doing with your other consoles. Definitely cut at least 12 to 18 dB out right there and you will probably come up with a considerably more functional mix.
Of course, if you want to keep doing it the way you are currently doing it, the idea of sending the master L&R to the Matrix and throttling it back there to whatever output level you want is a fine idea too.
Either method will work fine, but by dialing back the input sensitivity (input trims) you can get more "headroom" on that input for unexpected louder noises. Personally, I don't think 6dB is enough headroom to have.
Re: Midas M32 Output Level
What you are really saying here is that the amp+speaker rig is too powerful for the venue. Your best option is to reduce the input gain on the amps or use attenuation in cross-overs. External attenuators such as a pair of Shure A15AS may also do the job. You will however obtain the best S/N ratio by simply turning down the amps. All forms of amplification add some noise, so it is a simple but important rule of thumb to try your best to avoid attenuation anywhere in your signal chain. A signal going into an endless chain of analog amplifiers and attenuators will sooner or later end up as pure noise even with the best of amps.
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Re: Midas M32 Output Level
You could stick one of these between the amps and the board, and lock it up someplace where no one will bump it.
http://www.bhphotovideo.com/bnh/con...118JQpL9D7ECS2hoCdofw_wcB&Q=&is=REG&A=details
You could stick one of these between the amps and the board, and lock it up someplace where no one will bump it.
http://www.bhphotovideo.com/bnh/con...118JQpL9D7ECS2hoCdofw_wcB&Q=&is=REG&A=details
Re: Midas M32 Output Level
He's also sending the system an output signal that is easily 20dB or more greater than in the past.
He's also sending the system an output signal that is easily 20dB or more greater than in the past.
Re: Midas M32 Output Level
I agree the input levels seem a bit high (-20 to -18dbfs equates to 0db) but then you were probably running at this level on the Studiolive.
What are the Meters on the L/R reading with the Fader at unity? Again you could aim for these to average -20 to -18 dbfs. As some one else suggested to set the Faders for the L/R at unity and achieve this you could use a DCA set to control all Channel Faders.
I agree the input levels seem a bit high (-20 to -18dbfs equates to 0db) but then you were probably running at this level on the Studiolive.
What are the Meters on the L/R reading with the Fader at unity? Again you could aim for these to average -20 to -18 dbfs. As some one else suggested to set the Faders for the L/R at unity and achieve this you could use a DCA set to control all Channel Faders.
Re: Midas M32 Output Level
Hi Guys
Many thanks to you all for the invaluable advice and assistance. Was at the theatre last night for the dress rehearsal and took the chance to reduce the channel levels to those suggested by Matt and others and what a difference! I was able to get a decent range of travel on the main L/R fader with the house amps gains re-adjusted to their normal position. The sound in the auditorium was noticeably better with a more open feel and without any sign of clipping as had been happening occasionally the previous night. Headroom was also noticeably better.
The option to run the L/R output through a Matrix (as suggested by Brian) has also been confirmed by Midas as the preferred solution (I sent them a support message on Sunday evening before I posted on here) and is one that I will keep in mind for future reference.
Once again, thanks for all your help. It's great to know that there are so many fellow soundies ready and willing to help.
Hi Guys
Many thanks to you all for the invaluable advice and assistance. Was at the theatre last night for the dress rehearsal and took the chance to reduce the channel levels to those suggested by Matt and others and what a difference! I was able to get a decent range of travel on the main L/R fader with the house amps gains re-adjusted to their normal position. The sound in the auditorium was noticeably better with a more open feel and without any sign of clipping as had been happening occasionally the previous night. Headroom was also noticeably better.
The option to run the L/R output through a Matrix (as suggested by Brian) has also been confirmed by Midas as the preferred solution (I sent them a support message on Sunday evening before I posted on here) and is one that I will keep in mind for future reference.
Once again, thanks for all your help. It's great to know that there are so many fellow soundies ready and willing to help.
Re: Midas M32 Output Level
A common error is to confuse how much gain something has with how much power it can produce.
A common error is to confuse how much gain something has with how much power it can produce.