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Discussion Starter · #1 ·
Hi all.


I've been playing around with the Revo and with DirectShow filters - especially with the iviaudio / auprocfx filters to get DPL2 out the revo. IMHO WinDVD's DPL2 sounds better than Revo's Circle Surround, at least my Divx files sound better (so far I've compared with Naruto and Hikaru no Go anime eps).


Previously, I have already set up my audio level using VE (playing on PowerDVD), and basically I needed to tone down my center and rear speaker levels in the Revo control panel. Everything registers at 70 dB on my Radio Shack meter - seems good, right?


However, when I play around with some DShow filter that allows amplifying the audio signal, it seems that the speaker level is capped to that particular level on the revo control panel. If the center channel is lowered -12 dB, and you use the amplification on the signal itself before rendering on the sound card, I found that the signal meter (on the revo CP) will NEVER exceed the -12 mark. I can boost all channel's volume, and my fronts would get louder and louder, but the center would not get past the -12 dB - resulting in the center channel sound to be eventually drowned out by the fronts.


Is this intentional? I thought the idea of sound leveling is that the incoming sound is reduced (by a specified dB) - so if you're reducing the center channel by 12 dB, if the signal is 80 dB at the start, it will be reduced to 68 dB. However, as the signal goes to 100 dB, the signal should still only be lowered by 12, resulting in 88 dB sound.


How does the revo reduces the volume here? I'm gonna do some more experimentation tonight and I'll see if I can get some more definite conclusion to these.
 

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Discussion Starter · #2 ·
I'm still not quite sure how the Revo is limiting stuff. I can amplify the actual wave signal (using DShow filter) and no matter how loud I play it, it won't exceed the level.


Also, if you have a signal that's playing near peak/clipping, you can still amplify the sound by increasing the master volume level on the revo CP. How is this possible? Unless the master volume control acts on the analog signal going out, it will still clip the DAC isn't it?


For those with low DVD playback volume, using Zoom Player and DC-DSP filter (a DShow filter), I can amplify all my audio channels to reference level and more. Video Essential sound level test now gives me 75 dB at 75% master volume. At first, I can only get to 70 dB with 100% volume. The DC-DSP amplification takes about 100 MHz CPU cycle (0.1 GHz). The filter can also resample to 24-bit resolution :).


And if you have a beefy enough machine, and want to do individual channel volume control (on a sound card that can't do it, like the Delta 1010), the DC-DSP filter fits the bill, since you can amplify individual channels.
 
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