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Old 28th August 2013, 09:33 AM   #1591
AllenB is offline AllenB  Australia
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Quote:
Originally Posted by bentoronto View Post
heterogeneous subs. The idea is to have a single (mixed) bass but to drive subs as different in type and location as possible,
This looks like two issues so, with regard to location it would seem to need more subs to make it work than other ways, what does it offer?. And with regard to type, what do you do with the differing responses between them?
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Old 28th August 2013, 10:28 AM   #1592
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This looks like two issues so, with regard to location it would seem to need more subs to make it work than other ways, what does it offer?. And with regard to type, what do you do with the differing responses between them?
In your room, each woofer and each location has a distinct sound. You want to mix-and-match.

Ben
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Old 28th August 2013, 10:31 AM   #1593
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snip
I tested the effect of an auxiliary sub. Both in simulation and IRL. Simulation suggested that best placement was the opposite wall
snip
What kind of simulation provides that kind of intelligence?

Ben
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Old 28th August 2013, 12:50 PM   #1594
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Quote:
Originally Posted by bentoronto View Post
In your room, each woofer and each location has a distinct sound. You want to mix-and-match.

Ben
You want that mix to produce the flattest response with the lowest ringing. Simply mixing different subs won't get you there. A good method seems to be Welti's SFM. Please see http://www.aes.org/e-lib/download.cf...80&name=harman

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What kind of simulation provides that kind of intelligence?

Ben
The latest REW beta 17 has a room simulator. Also check out New program for Room Response Simulation
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Old 30th August 2013, 05:27 PM   #1595
Juhazi is offline Juhazi  Finland
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Quote:
Originally Posted by bentoronto View Post
What kind of simulation provides that kind of intelligence?

Ben
hunecke.de | Loudspeakers Calculator

enable Java application

You can simulate mains and up to 4 subs. Each speaker can be positioned in 3D and mic too. Nice! Choose speakers from the list (ones that have performance closely to your own)

Actually the program does not make any suggestions.. But by moving the sub #2 around I just watched how the summed response behaves.
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Old 30th August 2013, 07:31 PM   #1596
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Very interesting. Thanks for the education. Very interesting. Much to think about.

Lucky me, I've only fussed with a single good seat over the past 56 years of my HiFi set-ups (granted, the first 10 years were mono).

These room models (and the CABS research too) are geometry calculators intended to address what for many must be the most basic issue: flat frequency response (esp. over a broad listening area). Yet all my life (till now?), i've been thinking about speaker placement considerations which only partly intersect with eigentone matters.

It would be really nice to have a room with more than 50% of the wall area fitting the model (not my over-furnished heavily draperied rooms). And speakers in small boxes that can be put anywhere you want (not like my large bipolar ESLs, Klipschorn corner horn, and giant OB sub screwed to the wall under a table).

Final thought: a mic will reveal the terrible dirty secret of room modes. Horrible to see the curves. But how come we don't hear them on music*? Just me or is it like cameras (and optical theory) being influenced by fluorescent or narrow-band lights but human eyes not the same way?

Ben
*the AR music room in Grand Central Station used to play that extended organ pedal in the second half of the Saint Saens 3rd Sym (Munch, Boston) and the walls shook just for that note played on AR3 speakers - so there are some revealing tests using music... but rare.
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Last edited by bentoronto; 30th August 2013 at 07:38 PM.
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Old 31st August 2013, 05:07 AM   #1597
AllenB is offline AllenB  Australia
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Horrible to see the curves. But how come we don't hear them on music*?
We can hear them until they're below some level. Even when not, they don't always sound bad after setup.
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Old 31st August 2013, 03:50 PM   #1598
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We can hear them until they're below some level. Even when not, they don't always sound bad after setup.
Toole points out you can hear broad envelopes but not narrow bumps in the freq compass. And by the way, people can't tell a lower-band bump from an upper-band cut.

So we need to look again at the traditional examination of eigentones that examines the distribution of room modes. When you have bunch of loudness in a somewhat broad band, say 50-65 Hz, we say "the speaker" has an awful boomy bass.

But as "broad" gets narrower, nobody notices. Which is what I said before.

Ben
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Last edited by bentoronto; 31st August 2013 at 03:53 PM.
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Old 1st September 2013, 01:50 AM   #1599
AllenB is offline AllenB  Australia
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Haven't you heard a bass guitarist playing a down a scale, and each note is obviously in balance until just one jumps out at a higher level (back down for the next one)?
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Old 1st September 2013, 03:05 AM   #1600
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Haven't you heard a bass guitarist playing a down a scale, and each note is obviously in balance until just one jumps out at a higher level (back down for the next one)?
I think my own example from the AR Music Room was actually more relevant because there are a quite a few ways for synthetic sound to be distorted from finger-tip to fold-back speakers (is that the right term?) to recording board, to speaker resonances etc.

There are any number of hearing "phenomena" that can only be demonstrated using hand-picked stimuli. I'm not saying narrow-band effects* can't be heard under certain conditions (and I gave an example) - just not usual to hear it with music.

Ben
*I suspect narrow-band cuts are twice as hard to "hear" as narrow-band boosts, except with hand-picked stimuli.
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