Help Using Calibration Mic on Denon 3808CI

**veajt00** · **11-10-08, 07:59 PM**

I'm experienced with home theater, but have very little experience with mics and calibration (outside of using auto calibration mics and a RadioShack SPL meter), so I was hoping to get some help from this forum.

I've had a Denon 3808CI for a little over a year. This receiver comes with a mic for Audyssey auto calibration to be plugged into a 3.5mm "MIC SETUP" port, but also allows you to use a third party mic plugged into the left audio-in RCA jack of an auxilary input on the front of the receiver. I've never got good results using the Audyssey mic (speaker distances and levels were always WAY off). I've been working with Denon customer support and have tried multiple Denon mics, and now they want me to mail in the receiver for repair.

Before doing that, I decided to try experimenting with the third party mic option. I purchased a Behringer ECM8000 calibration mic and a Behringer PS400 power supply to supply phantom power to the mic. I also got the necessary cables, including an XLR female to RCA male to connect the "mic thru" on the power supply to the V.AUX-L RCA input on the front of the Denon.

My initial results were very promising - no issues in my first three measurement positions. Unfortunately, the receiver did not "hear" my rear speakers, or the mic was not sensitive enough, when I moved the mic to the front of my listening area. However, after compressing my measurement area so the set-up could complete, I actually got distance and level measurements that were accurate for the first time ever! The EQ curves seem reasonable, and the receiver sounds much better then it ever has before, so I'm currently using this set-up.

However, since I'm learning as I go, I can't help but think I did something wrong. From reading a little bit on these forums, the mic I got appears to be sensitive enough, so why couldn't the receiver detect the rear speakers when I moved the mic three feet away? There might be a problem with impedence matching, but once again, I'm not sure how to tell if this is an issue or how to fix it.

Thanks a lot for any help you can provide!

**bjs** · **11-10-08, 08:24 PM**

If I understand you correctly, you are trying to connect the ECM 8000 to your line level auxilary input.

This will not work since the ECM8000 doesn't output line levels. You will need to use a mic preamplifier. I use a Xenyx 802 for example (but any solid state mic-preamplifier should do).

**veajt00** · **11-11-08, 01:57 AM**

Thanks a lot for the reply. I did some research, and it looks like two of the best mic preamp options for my use are the Behringer XENYX 802 and the M-Audio Audio Buddy. Both are available for around $60. Any comments as to which is better for my application? I like the simplicity of the Audio Buddy, but it appears that the Behringer has got slightly better reviews.

Thanks again for your help...

**bjs** · **11-11-08, 01:54 PM**

As mentioned I use the 802 and it works fine. Brucek has posted setup info (do a search).

I've never used the M-Audio Buddy so can't comment although, based on a quick look, I didn't see any reason for it not to work.

**tonyvdb** · **11-11-08, 02:00 PM**

Just out of curiosity when your using the Denon's supplied mic are you placing it on a trypod? alot of people dont and this will cause all sorts of problems.

**veajt00** · **11-11-08, 02:12 PM**

Quote:

tonyvdb wrote:

Just out of curiosity when your using the Denon's supplied mic are you placing it on a trypod? alot of people dont and this will cause all sorts of problems.

Yes I am. I'm anxious to try the replacment mic Denon has sent me - it should arrive any day. Although I am enjoying learning more about mic and room calibration - I may end up getting REW and diving deeper once I have the right equipment.

After reading more reviews and info, including the guide available on this site, I'm leaning toward the Behringer 802 unit. It looks like it would work for my application, and give me the flexibility for more detailed room calibration down the road if needed.

Thanks again for the help.

**Kal Rubinson** · **11-11-08, 03:22 PM**

Quote:

veajt00 wrote:

Thanks a lot for the reply. I did some research, and it looks like two of the best mic preamp options for my use are the Behringer XENYX 802 and the M-Audio Audio Buddy. Both are available for around $60. Any comments as to which is better for my application? I like the simplicity of the Audio Buddy, but it appears that the Behringer has got slightly better reviews.

Thanks again for your help...

How can you get the calibrations for either of these into the Denon?

Kal

**veajt00** · **11-11-08, 07:43 PM**

Quote:

Kal Rubinson wrote:

How can you get the calibrations for either of these into the Denon?...

I don't think you can. The Denon manual states "Only a professionally certified installer should ever connect a professionally-calibrated microphone to the V.AUX L input on the front panel." So I'm assuming that a custom installer might have the properly calibrated mic? However, I've had success with the ECM8000, and I haven't even used it properly yet (with a mic preamp). The issue with the Denon is that in order to use Audyssey Dynamic Equilization and Dynamic Volume, you have to run the auto set-up. So I can either use the Denon supplied mic that gives VERY poor results, or experiment with a third party mic (which has shown some promise so far).

Eventually I'll probably send the receiver in for repair before it's out of warranty, but if I can get the third party mic to work, it could be a good temporary solution - plus I'm having fun learning about all this room EQ stuff...

**Hakka** · **11-13-08, 09:32 PM**

As Kal said there's no way to get a cal file into the denon. The aux mic connector is intended for the mic that comes with the audyssey pro kit, with the cal file on the connected pc running the audyssey software.
Posted via Mobile Device

**Kal Rubinson** · **11-13-08, 11:42 PM**

Quote:

veajt00 wrote:

However, I've had success with the ECM8000, and I haven't even used it properly yet (with a mic preamp).

How are you assessing success? Are you measuring it or are you just happy with it subjectively.

Kal

**veajt00** · **11-13-08, 11:44 PM**

Quote:

Hakka wrote:

As Kal said there's no way to get a cal file into the denon. The aux mic connector is intended for the mic that comes with the audyssey pro kit, with the cal file on the connected pc running the audyssey software.
Posted via Mobile Device

Thanks for the tip. I'm going to look around to see if there are any installers in the Pittsburgh, PA area that might be able to help me out. I checked the Audyssey website, but unfortunately they didn't any that were local.

**veajt00** · **11-14-08, 12:53 AM**

Quote:

Kal Rubinson wrote:

How are you assessing success? Are you measuring it or are you just happy with it subjectively.

Kal

Compared to the supplied Denon Audyssey mic, which never calculated correct speaker distances or levels, calibration performed with the EMC8000 results in accurate speaker distances and levels. However, because the EMC8000 is not calibrated for Audyssey, I suspect that the EQ curves resulting from this calibration are not "accurate", even though it sounds good.

Is it possible to use REW to measure how well Audyssey is improving my room EQ? I've already got the EMC8000 and I have a Behringer 802 preamp on order, so I think the only remaining equipment I would need is a sound card for my laptop and some more cables. What do you think?

**brucek** · **11-14-08, 07:05 AM**

Quote:

Is it possible to use REW to measure how well Audyssey is improving my room EQ?

Yes, read the REW HELP files and also REW Cabling Basics.

brucek

**RollsRoyce** · **11-22-08, 11:10 AM**

Some Denon receivers have a known issue with the Audyssey mic setup, and this may be why Denon has asked you to return it for repair. One indicator is speaker distances being way off, usually showing distances of 2 feet or less. The sub is an exception, since Audyssey will modify its delay/reported distance to fix phase issues, so reported sub distance being different from actual distance is common for Audyssey-equipped systems. Another indicator to the problem is lightly scratching a fingernail across the top of the Audyssey mic while it's connected. If you hear any sound from the speakers while doing this, the receiver needs to be repaired.

**veajt00** · **11-22-08, 11:45 PM**

Thanks. I read similar things over in the AVS forums. I tried scratching the mic, and didn't hear anything unless I turned the volume up to the maximum, then I thought I heard something. Regardless, I'm going to send the receiver in for repair when I can find a good time to be without my home theater for two-three weeks.

On a slightly different topic, I just got started with REW and would like to use it to measure all my speakers and adjust them with the manual EQ in the receiver. Does anyone have any tips to do this on the 3808? I've tried sending the test signal from REW to each speaker via the external analog inputs on the Denon. This seems to work, but the Denon can't apply any EQ or bass management to the external inputs. So I can measure my speaker levels, but can't measure the impact I might make with the manual EQ. I'm just getting started, so any help would be appreciated. Thanks!

**brucek** · **11-23-08, 10:04 AM**

Quote:

I've tried sending the test signal from REW to each speaker via the external analog inputs on the Denon

Connect the REW signal to the AUX or CD input of the receiver with a Y-Adapter and place the receiver in stereo mode. This takes care of the two mains. Then simply disconnect the mains and connect the rears to the mains output to test them, etc.....

brucek

**RollsRoyce** · **11-23-08, 12:54 PM**

Quote:

brucek wrote:

Connect the REW signal to the AUX or CD input of the receiver with a Y-Adapter and place the receiver in stereo mode. This takes care of the two mains. Then simply disconnect the mains and connect the rears to the mains output to test them, etc.....

brucek

Wow. Excellent, idea, Bruce. I'd never have thought of that!

**veajt00** · **11-23-08, 03:19 PM**

Thanks for the advise - great idea!

This raises some more questions for me:
1. Why does REW have to be in stereo - why not direct or via the external analog inputs? Is this because stereo mode is the only way to get the Denon 3808 to manage the base?
2. If I want to calibrate each speaker individually, can I use stereo mode, but only hook up one speaker at a time? The Denon allows you to apply a different EQ curve to each speaker.
3. Do I need to recalibrate levels and the SPL reading in REW before I measure each speaker or pair of speakers?

Thanks for the help!

**brucek** · **11-24-08, 09:59 AM**

Quote:

1. Why does REW have to be in stereo - why not direct or via the external analog inputs? Is this because stereo mode is the only way to get the Denon 3808 to manage the base?

Base management isn't active using the direct inputs. REW is a mono signal, so no soundfields are allowed. That leaves stereo mode...

Quote:

2. If I want to calibrate each speaker individually, can I use stereo mode, but only hook up one speaker at a time?

Yes.

Quote:

3. Do I need to recalibrate levels and the SPL reading in REW before I measure each speaker or pair of speakers?

Yes.

brucek

**Kal Rubinson** · **11-24-08, 11:16 AM**

Quote:

brucek wrote:

Base management isn't active using the direct inputs. REW is a mono signal, so no soundfields are allowed. That leaves stereo mode...

True but surely you can feed only the L or R channel inputs and leave it in stereo mode. No?

Kal

**veajt00** · **11-24-08, 01:34 PM**

Thanks, Bruce.

Kal, I thought that was the second question I asked - am I misunderstanding something?

I started playing around with measurements last night. I have two subs - a larger Paradigm and smaller Def Tech, both placed to the front of my listenting position on each side of the TV - the larger Paradigm is in the corner on the left and the Def Tech is against the wall on the right (unfortunately I have a large, open floor plan for my home theater). I measured each sub individually using the External Analog Inputs to get a full frequency response (no bass management) and got pretty well what I expected. However, when I tested both of them together (which is how I've been running my home theater), I got about a 15 dB dip at around 60 Hz. I've read that positioning two subs can be tricky, but until I started playing with REW, had no way of measuring them. Now I feel like I should try to optimize their placement to minimize the drop at 60 Hz. Unfortunately, I'm kind of limited due to the shape of the room as to where I can place them. I'll try to post graphs of the responses as I learn that feature in REW. Any suggestions regarding placement or things to try would be appreciated. FYI, the Paradigm has a phase control that I played with, but it did not help the dip (The Def Tech does not have phase control). Thanks...

**Kal Rubinson** · **11-24-08, 01:43 PM**

Quote:

veajt00 wrote:

Thanks, Bruce.

Kal, I thought that was the second question I asked - am I misunderstanding something?

Disconnecting a speaker is not the same task as not connecting one input.

Kal

**brucek** · **11-24-08, 03:21 PM**

Quote:

True but surely you can feed only the L or R channel inputs and leave it in stereo mode. No?

Of course. I think you mis-interpret my meaning - it was two answers in one statement.

1.Bass management isn't active using the direct inputs. This is say that the direct inputs are fine, except you won't enjoy bass management.

2. REW is a mono signal, so no soundfields are allowed. That leaves stereo mode... This is to say you can connect the mono signal to the left and right AUX input to enjoy base management, but be careful not to select soundfields - stereo only. It's advantageous to run two speakers at once (both mains) since their interaction and possible cancellation is important to see and would be missed if only one speaker was used at a time.

Quote:

I've read that positioning two subs can be tricky

Solved by co-locating them. Subs aren't localizable, so stack them together.

brucek

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