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Old 6th November 2012, 10:45 AM   #28971
bcarso is offline bcarso  United States
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Originally Posted by kgrlee View Post
Actually another surprising finding is that the most important performance factor in Blind Listening Tests is accurate midrange especially on voices. This holds for headbanging pop teenager as much as the guy who insists on using only his own recordings made with his own mikes. Believable voices are essential for suspension of belief. Hyped speakers do badly in Blind Listening Tests.
For several years I did the electronics for small powered speakers. Although the first conscious and enunciated response of a typical listener was related to how much bass was perceived, the relative flatness of the midrange, even if not noted as such, was indeed paramount in distinguishing the given product from comparable ones. And the equalization required was sometimes as simple as a passive or bootstrapped bridged-T network ahead of the power amp.

Once in a while the industrial design married well with the acoustical, and actually resulted in decent dispersion/directivity and absence of prominent diffraction effects. That really helped a lot, and with frequency-dependent compression/limiting resulted in some fairly credible near-field listening possibilities. And all of this for a parts cost well below someone's fancy film cap, and reliability based on customer complaints and returns at the few-hundred parts-per-million level.
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Old 6th November 2012, 11:27 AM   #28972
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Originally Posted by bcarso View Post
For several years I did the electronics for small powered speakers. .. and with frequency-dependent compression/limiting resulted in some fairly credible near-field listening possibilities. And all of this for a parts cost well below someone's fancy film cap, and reliability based on customer complaints and returns at the few-hundred parts-per-million level.
Brad, did you by any chance do the JBL LSR25p?

A friend of mine has 8 for a surround sound system. He needs to repair the electronics for some.

I called my version of dis Powered Integrated Super Sub technology but for some reason, Marketing never liked the name.

Last edited by kgrlee; 6th November 2012 at 11:31 AM.
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Old 6th November 2012, 11:38 AM   #28973
fas42 is online now fas42  Australia
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Frank, I'd be interested in these $20 speakers as that's all I can afford as a beach bum. I'm hoping you won't tell me they were made by Sydney virgins.
Sydney ... virgins ... why does the term "oxymoron" seem to flit into my consciousness ... ,

Nah, they're nothing special, made by a huge Taiwanese speaker factory, name escapes me at the moment. They sound pretty rough and somewhat dull when cold; have to be hammered hard for a hour or two at least with serious pub rock or equivalent to come to life, suspensions are pretty ordinary until thoroughly warmed up ...

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Following Ludwig's score means an accurate piano recording played at home at the correct level will clip a 1000W amp even with a speaker of 94dB/W @ 1m sens. It justs clips less often compared to 50W.
Huh?!! Forgetting about stereo setups, doubling the power gives you an extra 3dB from the speaker: so 1W, 94db; 2W; 97; 4W, 100; 8W; 103; 16W, 106; 32W, 109; 64W, 112; 128W, 115; 256W; 118. We're now at a level just below the maximum that can be experienced by a player in an orchestra, seated immediately in front of the brass section. A solo piano is not as loud as that, the amp's power is not a problem!

We do have a upright piano at home, in the listening area; using that as a reference, four clicks below maximum volume on a typical classical recording, say Brendel sonatas, gives me equivalent SPLs, with considerably better tone from the recording, as it should with a top notch Steinway, etc, at his service ...

I am aware that most hifi playback of piano is rather insipid and pedestrian, but it doesn't need to be ...

Frank
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Old 6th November 2012, 02:06 PM   #28974
RNMarsh is offline RNMarsh  United States
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There is a huge difference between liking and enjoy the music and realistic sounding systems. I listen to a lot of junk equipment at home.... Sat. radio box, mono iPOD player, car audio and thoroughly enjoy listening thru them to the music I love. Only my main rig sounds a lot closer to real than the others. Its the one system I turn to when I want max performance with my music. And, that isnt even most of the time. It's just good to know i have the choice.

Last edited by RNMarsh; 6th November 2012 at 02:09 PM.
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Old 6th November 2012, 02:08 PM   #28975
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Originally Posted by Tom Danley View Post
Hi

Fwiw, sound does not ďheatĒ air with the exception of what ever energy is absorbed. At the same time, air behaves following gas law and so if you compress it momentarily, itís pressure rises but so does itís temperature as you have the same heat energy confined into a smaller space, an important detail.
As I stated, the energy density will heat the air as it passes through. But it is a transient condition of course, it will track the frequency but will remain on average, the same as the rest of the room.

During the rarefaction and compression, the temperature will be varying. My question was, given for example, 4 acoustic watts travelling through a 1 square inch column of air, how much of a rise could one expect, therefore how much of a modulation of velocity.

Your first sentence is with respect to absorbtion. I was not speaking of that. Your second is more aligned with my statements.

jn
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Old 6th November 2012, 02:16 PM   #28976
RNMarsh is offline RNMarsh  United States
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Originally Posted by fas42 View Post
Huh?!! Forgetting about stereo setups, doubling the power gives you an extra 3dB from the speaker: so 1W, 94db; 2W; 97; 4W, 100; 8W; 103; 16W, 106; 32W, 109; 64W, 112; 128W, 115; 256W; 118. We're now at a level just below the maximum that can be experienced by a player in an orchestra, seated immediately in front of the brass section. A solo piano is not as loud as that, the amp's power is not a problem!

I am aware that most hifi playback of piano is rather insipid and pedestrian, but it doesn't need to be ...

Frank
256W but at 1 meter from the speaker. Depending on room volume/size and speaker directivity, distance to the listening position, room characteristic et al, the power needs will be greater than this minimum number. And, most speakers are much lower than 94db. Lots more power needed.
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Old 6th November 2012, 02:18 PM   #28977
SY is offline SY  United States
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As I stated, the energy density will heat the air as it passes through. But it is a transient condition of course, it will track the frequency but will remain on average, the same as the rest of the room.
Is that actually true? We are adding energy, after all...
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Old 6th November 2012, 02:22 PM   #28978
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Is that actually true? We are adding energy, after all...
The vast, vast bulk of it is just passin through.

jn
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Old 6th November 2012, 02:41 PM   #28979
SY is offline SY  United States
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Well, if you want to pick nits, I thought I'd throw a few your way.
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Old 6th November 2012, 02:44 PM   #28980
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Well, if you want to pick nits, I thought I'd throw a few your way.
You were just hoping to use your tubey/speaker thingies to keep your keester warm in that god-forsakin part of the country you now call home..

'twas 20 degrees F this mornin here.. sheesh.

jn
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