Limiting/compressing solution for AT4073a at DVinfo.net

Nathan Taylor · January 19th, 2005, 05:52 AM

Hi guys,

I really need your advice......

I have a sony dsr250 camera and recently purchased an AT4073a mic for it. The AT sounds great (huge improvement over the standard sony mic!) at low to mid levels but overloads on very high levels.
Whats the best solution for this?
I mainly shoot weddings so im shooting indoor and outdoor and recording loud and quiet passages without warning.
I need a solution that is permanent (ie - i dont have to fiddle with manual levels every second shot) and doesnt compromise the sound quality of the AT.
Ive looked at several products on the net like the beachtek's for example but its all left me a bit confused.

Any help here would be greatly apreciated :)

Regards, Nathan.

Matt Gettemeier · January 19th, 2005, 06:28 AM

You have two choices... you need a good limiter in the signal path... either built-in to the camera or provided by a mixer / Beachtek type device... OR you need to set both in-cam channels to run off the same mic and set ch1 for the desired level under "normal" conditions and set ch2 lower so you have a track to go to in post...

Jay Massengill · January 19th, 2005, 09:08 AM

You'll first need to determine whether the overload is occuring at the mic input or afterwards at the recording level controls.
Experiment at a loud event. Turn the recording levels down until the meters are indicating a mid-range level during loud sounds. If you can still hear distortion when monitoring from the camera, then the mic is overloading the input and you'll have to use either a small amount of attenuation or a limiter in an external device like a SoundDevices MixPre. Studio1 now makes a "BeachTek" type of box that outputs on an XLR connector. (Actually they make two, but only the Pro version passes phantom power.)
You could use that as a variable attenuator depending on the loudness of your situation.
If you're not hearing distortion on loud sounds when the meters are reading mid-range, but only when they peak too high because the controls are set for a quieter passage of your event, then you could employ an internal limiter if that camera has one. I don't remember, and you may only be able to choose manual or full auto. If that's the case, then you're back to using an external limiter or set your controls for a safety channel like Matt suggested.

David Ennis · January 19th, 2005, 10:54 AM

What's no doubt confusing you can be cleared up by a lesson I previously learned from Jay and have come to understand pretty well with my GL2. Its that the level meters on cams that have them don't indicate what's happening at the input. They indicate the amplitude of the signal that's being applied to the cam's analog to digital converter. That's an important thing to monitor also, because there is no "headroom" above 0 dB at that point.

I'd bet serious money that the mic is overloading the cam. The 4073 is a very hot mic, with a stronger output than other mics (e.g., the Senn ME66) already known for their ability to overload camcorder input circuits. Check the specs page in your manual and you'll probably find that the mic input expects voltage levels somewhere between -30 and -50 dB (while you're at it, see if this is adjustable at all). Anyway, the 4073's voltage is -23 dB at sound pressure levels of 94 dB (less loud than a rock band)!

The BeachTek DXA-8 with its limiters may be your best solution because it mounts to the bottom of the camera and then you can either rove around or mount the combination to a tripod. Either way, once you set it you can forget about input levels and concentrate on filming. The DXA-8 offers addtional features and benefits as well.

One more thing, though. You will need an in line attenuator like the AT8202 to bring the 4073's output down to the working input level of the DXA-8, or else you'll have the DXA-8 itself clipping loud passages and be REALLY frustrated.

Don Bloom · January 19th, 2005, 12:10 PM

I use a Senn ME66 so it's slightly different but I also use a PROCO -10db attenuator on the mic during the reception and it makes a hugh difference. The built in 20db attenuator is too much (IMO) and NOT using 1 can cause clipping that is beyond control. Another thing to try is set your shotgun to AGC (on that camera its really a soft limiter) on channel 1 with the 10db attenuator, and set channel 2 to manual, drop the level to about 35-50% and now you've got 2 tracks to work with. Granted while I'm using pd150's not the 250, the audio circuitry is pretty much the same and I've been using this setup for about 2 years now and the audio works very well. Prior to that I was "riding the wheel" and it was a major PITA!

For ceremonies I use the split set up, shotgun to channel 1 on AGC, grooms wireless to channel 2 on manual and then I use the 20db attenuation on that mic because its very strong. I don't use the -10db on the shotgun during the ceremony and in the last 2 years and 121 weddings I've only had 1 audio challenge and that was where the lecturn mic wasn't turned on so for the 1st few moments of the 1st readers speaking it was virtually inaudible.
Fortunately, I clip a lav to that mic and run it to my 2nd 150 so I still had good stuff. (whew)
Play around a bit with the different settings and try the attenuator. Hey for 20 bucks the worst thing is it doesn't work for you but I think it will.
BTW, use a GOOD set of headphones to monitor and learn to trust your ears!

Don B

Nathan Taylor · February 8th, 2005, 05:26 AM

Hey thanx everyone for their input.

After much web searching ive decided to go with a sound devices mixpre.
This will cover all the requirements;
# xlr in and outs
# phantom power
# visual led monitors for future use with two crew shoots
# small (ish) size
# excellent limiting control

Only problem is i cant aford one right now lol so it will have to wait a few months.
If anyone has one up for sale second hand let me know...
I take it the mixpre is completely identical to the shure version except the badge or are there reasons to pay extra for the shure one?

In the meantime i will use an AT8202 inline barrel attenuator on the mic.

Many thanx to all who gave advice - u guys rock :)

Ty Ford · February 8th, 2005, 08:52 AM

You show rare wisdom with you choice to wait, save and buy the MixPre. I reviewed it years ago and subsequently bought the larger 442 when it came out because it does more things.

I don't think it's any different than the Shure version. Why not call or eamil the caps at Sound Devices and ask them. If you do, say "hi" for me.

Regards,

Ty Ford

January 19th, 2005, 05:52 AM	#1
Nathan Taylor New Boot Join Date: Nov 2004 Location: New Zealand Posts: 19	Limiting/compressing solution for AT4073a Hi guys, I really need your advice...... I have a sony dsr250 camera and recently purchased an AT4073a mic for it. The AT sounds great (huge improvement over the standard sony mic!) at low to mid levels but overloads on very high levels. Whats the best solution for this? I mainly shoot weddings so im shooting indoor and outdoor and recording loud and quiet passages without warning. I need a solution that is permanent (ie - i dont have to fiddle with manual levels every second shot) and doesnt compromise the sound quality of the AT. Ive looked at several products on the net like the beachtek's for example but its all left me a bit confused. Any help here would be greatly apreciated :) Regards, Nathan.

January 19th, 2005, 10:54 AM	#4
David Ennis Fred Retread Join Date: Jul 2004 Location: Hartford, CT Posts: 1,227	What's no doubt confusing you can be cleared up by a lesson I previously learned from Jay and have come to understand pretty well with my GL2. Its that the level meters on cams that have them don't indicate what's happening at the input. They indicate the amplitude of the signal that's being applied to the cam's analog to digital converter. That's an important thing to monitor also, because there is no "headroom" above 0 dB at that point. I'd bet serious money that the mic is overloading the cam. The 4073 is a very hot mic, with a stronger output than other mics (e.g., the Senn ME66) already known for their ability to overload camcorder input circuits. Check the specs page in your manual and you'll probably find that the mic input expects voltage levels somewhere between -30 and -50 dB (while you're at it, see if this is adjustable at all). Anyway, the 4073's voltage is -23 dB at sound pressure levels of 94 dB (less loud than a rock band)! The BeachTek DXA-8 with its limiters may be your best solution because it mounts to the bottom of the camera and then you can either rove around or mount the combination to a tripod. Either way, once you set it you can forget about input levels and concentrate on filming. The DXA-8 offers addtional features and benefits as well. One more thing, though. You will need an in line attenuator like the AT8202 to bring the 4073's output down to the working input level of the DXA-8, or else you'll have the DXA-8 itself clipping loud passages and be REALLY frustrated. __________________ "Nothing in the world can take the place of persistence..." - Calvin Coolidge "My brain is wired to want to know how other things are wired." - Me

February 8th, 2005, 08:52 AM	#7
Ty Ford Inner Circle Join Date: Nov 2004 Location: Baltimore, MD USA Posts: 2,337	You show rare wisdom with you choice to wait, save and buy the MixPre. I reviewed it years ago and subsequently bought the larger 442 when it came out because it does more things. I don't think it's any different than the Shure version. Why not call or eamil the caps at Sound Devices and ask them. If you do, say "hi" for me. Regards, Ty Ford __________________ Ty Ford's Audio Bootcamp Field Guide Ty Ford's Audio Video Blog

January 19th, 2005, 06:28 AM	#2
Matt Gettemeier Major Player Join Date: May 2003 Location: St. Louis, Missouri Posts: 936	You have two choices... you need a good limiter in the signal path... either built-in to the camera or provided by a mixer / Beachtek type device... OR you need to set both in-cam channels to run off the same mic and set ch1 for the desired level under "normal" conditions and set ch2 lower so you have a track to go to in post...

January 19th, 2005, 09:08 AM	#3
Jay Massengill Trustee Join Date: Jul 2003 Location: Burlington Posts: 1,976	You'll first need to determine whether the overload is occuring at the mic input or afterwards at the recording level controls. Experiment at a loud event. Turn the recording levels down until the meters are indicating a mid-range level during loud sounds. If you can still hear distortion when monitoring from the camera, then the mic is overloading the input and you'll have to use either a small amount of attenuation or a limiter in an external device like a SoundDevices MixPre. Studio1 now makes a "BeachTek" type of box that outputs on an XLR connector. (Actually they make two, but only the Pro version passes phantom power.) You could use that as a variable attenuator depending on the loudness of your situation. If you're not hearing distortion on loud sounds when the meters are reading mid-range, but only when they peak too high because the controls are set for a quieter passage of your event, then you could employ an internal limiter if that camera has one. I don't remember, and you may only be able to choose manual or full auto. If that's the case, then you're back to using an external limiter or set your controls for a safety channel like Matt suggested.

January 19th, 2005, 12:10 PM	#5
Don Bloom Inner Circle Join Date: Jan 2003 Location: Chicago, IL Posts: 6,609	I use a Senn ME66 so it's slightly different but I also use a PROCO -10db attenuator on the mic during the reception and it makes a hugh difference. The built in 20db attenuator is too much (IMO) and NOT using 1 can cause clipping that is beyond control. Another thing to try is set your shotgun to AGC (on that camera its really a soft limiter) on channel 1 with the 10db attenuator, and set channel 2 to manual, drop the level to about 35-50% and now you've got 2 tracks to work with. Granted while I'm using pd150's not the 250, the audio circuitry is pretty much the same and I've been using this setup for about 2 years now and the audio works very well. Prior to that I was "riding the wheel" and it was a major PITA! For ceremonies I use the split set up, shotgun to channel 1 on AGC, grooms wireless to channel 2 on manual and then I use the 20db attenuation on that mic because its very strong. I don't use the -10db on the shotgun during the ceremony and in the last 2 years and 121 weddings I've only had 1 audio challenge and that was where the lecturn mic wasn't turned on so for the 1st few moments of the 1st readers speaking it was virtually inaudible. Fortunately, I clip a lav to that mic and run it to my 2nd 150 so I still had good stuff. (whew) Play around a bit with the different settings and try the attenuator. Hey for 20 bucks the worst thing is it doesn't work for you but I think it will. BTW, use a GOOD set of headphones to monitor and learn to trust your ears! Don B

February 8th, 2005, 05:26 AM	#6
Nathan Taylor New Boot Join Date: Nov 2004 Location: New Zealand Posts: 19	Hey thanx everyone for their input. After much web searching ive decided to go with a sound devices mixpre. This will cover all the requirements; # xlr in and outs # phantom power # visual led monitors for future use with two crew shoots # small (ish) size # excellent limiting control Only problem is i cant aford one right now lol so it will have to wait a few months. If anyone has one up for sale second hand let me know... I take it the mixpre is completely identical to the shure version except the badge or are there reasons to pay extra for the shure one? In the meantime i will use an AT8202 inline barrel attenuator on the mic. Many thanx to all who gave advice - u guys rock :)