Any idea why a 50hz tone is recommended when setting gains using a DMM?

[Flex68 10+ year member]

Another reason that a 50Hz test signal might be the signal of choice is when setting output on one's sub amp.

Fs / enclosure tuning in a general range of 25-35, with most low pass x's set at 60-80Hz----> median freq around 50ish

 

[keep_hope_alive Premium Member]

I understand the suspicion that a typical noob will try to turn the bass up as much as he possibly can, because he thinks this sounds uber cool or something. This is a good case for using DMM. However, people who are after SQ bass (e.g those into listening normal instrumental music, rock, etc, at healthy volume and without exaggerating any part of frequency range relative to the recording) can turn up the gain only up the the point where the sub stage blends well with the front stage, as suggested by ears using a good set of home speakers or headphones as a reference or by the means of RTA setup. This is how I set my gains. I suspect if I get the DMM and apply the DMM method, my subwoofer gain will be below that DMM says it could be.. I do have to try it some day. my 2c.

agreed and likewise.

 

[thorshammer1 10+ year member]

There is absolutely no way to ensure you have a clean signal when setting gains with a dmm.

 

[psych0ticnemes1 5,000+ posts]

There is absolutely no way to ensure you have a clean signal when setting gains with a dmm.

I guess close enough, is close enough.

 

[the727kid 10+ year member]

Saw a video once proving that using a DMM is actually a bad method. Showed setting gains with DMM perfect at 50hz, good on O-scope as well. Then tested in 30hz range and had significant clipping.

Using your ears and being smart with the volume knob is the best way IMO. If you can't hear clipping, you sure can smell it //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[thorshammer1 10+ year member]

Personally I use a hand held Velman Oscope. Have for yrs. I may break softparts such as surrounds from over excursion but I dont burn coils up ever lol

 

[psych0ticnemes1 5,000+ posts]

Personally I use a hand held Velman Oscope. Have for yrs. I may break softparts such as surrounds from over excursion but I dont burn coils up ever lol

Can't F up with an o-scope.

I'm in NY too. You don't have term lab by chance do you? lol

 

[thorshammer1 10+ year member]

Can't F up with an o-scope.
I'm in NY too. You don't have term lab by chance do you? lol

Sorry need to update profile lol I do indeed have a tl. I'm the turnkey promoter for dbdrag here in Nevada. I left NY about a yr and a half ago to go to work for DC fulltime.

I do however know alot of folks up there with a TL.

 

[psych0ticnemes1 5,000+ posts]

Sorry need to update profile lol I do indeed have a tl. I'm the turnkey promoter for dbdrag here in Nevada. I left NY about a yr and a half ago to go to work for DC fulltime.
I do however know alot of folks up there with a TL.

Well clear your PMs and hit me up with some names! lol.

 

[zako 10+ year member]

I got hold of a cheap DMM and tested the voltage of my woofer and subwoofer channels (both are 4ohm). At first the numbers seemed to be off. Then I realized that the test tones I used were not 0db. Got my USB key with the realmofexcursion 45Hz and 100Hz test Mp3s. I checked with foobar2000's spectrum graph to make sure they're 0dB. The subwoofer gain position was originally calibrated by ear to blend with the front speakers. The subwoofer channel returned 42 volts, which is exactly spot on, with the engine on and head unit volume at a little higher than normal position. (Amp is rated for about 450watts in bridged mode). I am a little surprised considering that I never set the gains intentionally to extract the most bass. It's good that I checked.

I also checked the voltage of the woofer channel. Got about 13V which corresponds to about 40watts. The amp is rated for 80watts. The speakers are Hybrid Audio Imagine. I listen fairly loud (for most of my friends and family member) with the high pass filter set at 60Hz, and these sound pretty good with the current setting. It's pleasing to know that you don't really need that much juice to get them to sound good. I didn't bother with taking the voltage reading of the tweeter channel. The reason is that most music content has nowhere near 0dB level in the highs anyways. I have a capacitor to protect them at lower frequencies.