Are 3dB steps too much (HT)?

JohnR · « **on:** 5 Jan 2004, 10:09 am »

Hi folks, time I got onto making my el-cheapo 6-channel attenuator. I have a 12-position switch...assuming I can calibrate 0dB to be maximum output (somewhat less than reference level

), what do you think of these steps?

0 dB
-3
-6
-9
-12
-15
-20
-25
-30
-40
-50
-infinity

peranders · « **Reply #1 on:** 5 Jan 2004, 10:54 am »

If you are going to use as a regular "pot" you should choose 1-1.5 dB at levels above - 20dB.

JohnR · « **Reply #2 on:** 5 Jan 2004, 02:22 pm »

Um.... perhaps I should rephrase the question

Given that I have a switch with only 12 stops on it, and that it will be used for HT where there is in fact a reference "0 dB" level, what's a good choice for attenuation steps?

Dan Banquer · « **Reply #3 on:** 5 Jan 2004, 02:26 pm »

It's O.K. to have 3 db steps for the first two steps, but the rest should be 2 db. This seems to work out o.k. for most folks. I would also recommend you move to a 24 position rotary switch.
d.b.

JohnR · « **Reply #4 on:** 5 Jan 2004, 02:32 pm »

OK, great, send me one!

Dan Banquer · « **Reply #5 on:** 5 Jan 2004, 03:35 pm »

If you wish I will send you a schematic. For someone who's motto is DIY or die trying I'm surprised you haven't fgured it out on your own.
d.b.

JohnR · « **Reply #6 on:** 5 Jan 2004, 03:47 pm »

Oh, puh-lease

Any chance for a cheap put-down, eh Dan?

Anyone out there interested in a sensible look at this?

Dan Banquer · « **Reply #7 on:** 5 Jan 2004, 03:50 pm »

No put down intended, just a little surprised. If you don't have ORCAD on your computer, send me a snail mail address and I will send out a copy.
d.b.

JohnR · « **Reply #8 on:** 5 Jan 2004, 04:57 pm »

In that case, I apologize.

Thanks, but I don't need a schematic for a stepped attenuator. I'm asking for opinions on attenuation steps for a 12-step attenuator for HT. I already have the switch, it cost a few bucks. Thought it might make an interesting challenge to figure out the best workable compromise using it instead of throwing dollars at the problem. No? I guess not.

So never mind!!! I'll just build it and report back later.

Dan Banquer · « **Reply #9 on:** 5 Jan 2004, 05:01 pm »

Good luck on your attempt; Don't be surprised if you find 12 steps are not enough.
d.b.

bubba966 · « **Reply #10 on:** 5 Jan 2004, 05:11 pm »

John,

I find that I usually watch moives at -15dB on my dial as reference level is just too loud.

Occasionally I run into a "quiet"movie that needs to be turned up to -12dB/-10db/-7dB.

If I need to turn it down I usually hit -18dB/-21dB/-25dB/-30dB/-40db.

Which makes my normal listening positions look like so.

-7dB
-10dB
-12dB
-15dB (standard DVD/LD viewing level)
-18dB
-21dB (standard TV viewing level)
-25dB
-30dB (standard CD/Gamecube/Xbox level)
-40dB

So I guess I usually only use about 8 or 9 different volume positions even though I have 1dB increments from +12dB over reference to -80dB below reference.

I'm sure a similar range of about 3dB for the first five or six steps is more than fine. Then 5dB for the next couple of steps. Then 10dB for the last few steps.

JohnR · « **Reply #11 on:** 5 Jan 2004, 10:54 pm »

Cool, thanks Brian

Will let you know how it works out. I guess I asked this in the wrong place.. .

bubba966 · « **Reply #12 on:** 5 Jan 2004, 11:08 pm »

You're welcome John.

And yeah, I 'spose this woulda been better asked in a different circle...

I guess you could always change it later if need be. But once you find where you usually listen to movies at, there isn't much need to go too far off the same point for most regular viewings.

And I'm sure something similar to what I listed above in your listening range will be more than adequate.