adjustble phase?

[CHUCKmfnNORRIS 10+ year member]

im getting a mb quart dsc 1500.1d amp and it has a "phase" dial. i've never seen a dial for the phase i have only seen the phase switch. what does it do and how do i tune it?

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[JimJ 5,000+ posts]

Instead of simply inverting the phase like a switch would do, it's adjustable across the range from 0 to 180 degrees.

 

[CHUCKmfnNORRIS 10+ year member]

still don't know how to tune it or what to listen for.

 

[CHUCKmfnNORRIS 10+ year member]

is there anyone who can explain it to me?

 

[ciaonzo 5,000+ posts]

Let me google that for you

 

[Pauliesnite93 10+ year member]

hay i just got the same amp and dont know what that is ether and what is the level is it like a gain on a amp

 

[ciaonzo 5,000+ posts]

lulz

 

[thch 10+ year member]

Adjustable phase is intended to aid in blending the subs to the midrange speakers, or act as a crude "delay" element.

first, you might like to understand phase. phase can apply to any periodic waveform or sequence. eg:

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 ...

a 180deg phase shift would be:

5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 ...

but in this case there are other possible phase shifts, like 36deg:

1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 ...

notice that the phase shift doesn't seem to matter. indeed, in most cases it doesn't. but the issue arises when you want two waves to combine correctly.

with most audio systems, there is a strong filter on the front midwoofers, and on the subwoofers. so the only bandwidth that the two compete are near the crossover. the adjustable phase acts as a small delay element over this bandwidth to try to allow them to blend.

the actual adjustable phase shift circuit isn't really constant over all the audio range -- it really is just based on an "all-pass" filter. as such, you should only expect to adjust the phase for one frequency.

this should be suitable for steep crossovers as well as any fine phase shifts for single tones.

 

[thch 10+ year member]

oh, and the listening, the phase shift will be the most difficult thing to listen for.

basically, most people don't set the crossovers up very well, nor the gains. this leads to a bit of a difficulty in even finding a case where the benefits are obvious.

if you didn't understand the above posts, you can just fiddle with it. just don't expect a huge change in the sound.