 04-28-08, 03:24 PM
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#109 (Link) |
Shack Administrator
Platinum Supporter Alias: Wayne Loc: Katy, Texas | User: #8 Since: Apr 2006 Posts: 2,185 |
| | Re: Is there a real benefit to preamps or two channel amps in HT?
brucek,
I see blaser sent you over here - hee hee!
Quote:
I don't think anyone can argue that this filter is also operating in the time domain?
| Sure we can. It’s impossible to make a case from an electronically generated, faux "room" mode that displays amplitude only but has no time domain element from reflections, boundary interference, etc. For instance, is it going to look different if you install some bass traps in the room?  It's merely a computer-generated loop that has no real-world significance.
Since I unfortunately did not save the REW files I used when I ran this experiment a while back, I decided to do it over and this time use a longer window for the waterfall. This time I let REW do the filtering and two modal filters (i.e. optimized for time domain) for my 42 Hz room mode were crafted, the primary one being centered at 42 Hz with a 10/60 bandwidth and cut 12 dB.
As before, a 300 ms window showed the same short-term reduction in ringing with modal filtering. But at 600 ms – different story. Here are the results with the 42 Hz peak level matched after equalization (as described in the linked thread). (Hitting F11 should get them both on-screen for easier comparision).
In fact, even with no level matching, we can see that modal filters made only a minor difference in reducing the 42 Hz mode's long-term ringing:
If you want to convince us otherwise, show us your in-room waterfalls (long window, please). IMO Ethan’s Audyssey report puts the matter to bed, unless someone can show a fundamental problem with his methods or procedures. As his chart above shows, Audyssey did not reduce ringing. I'm sure my experiments aren't as sophisticated as his, but I'm getting the same results every time.
Regards,
Wayne
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