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Speaker Asylum General speaker questions for audio and home theater. |
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Speaker Asylum General speaker questions for audio and home theater. |
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In Reply to: RE: Dynamics posted by hahax@verizon.net on April 2, 2024 at 06:06:09:
It would seem that dynamics and what does reproducing the whole signal mean is confusing .
For Example, people tend to look at the SPL they measure or an RMS drive voltage as an indicator of what's going on and so far as the amount of heating or work being done over a period of time, that is true.What is terrifically different is the steady heating value of a sine wave and a random signal who's average heating value is identical, BUT the peak values may be (+20dB) 100 times or more greater than the average BUT that not shown in an RMS averaged measurement like a Voltmeter or sound level meter (unless it has a peak hold function like some fancy ones do have).
How does this matter? Well Music IS such a signal, even the most compressed FM radio rock usually has around a +10dB crest factor or peaks that are 10X the average power. Most "Audiophile" level recordings are at least +20dB to 30dB crest factor meaning the short peaks are 100 to 1000 times larger than the average power.
So lets say you had a 85dB 1W/1M sensitive speaker and a 100Wrms amplifier and you sat 4 meters away.Ok how loud can one be assuming free field radiation? 100W is +20dB over 1W so 105dB at 1M or 93dB at the chair (assuming no power compression). OK so what about other signals like flat pink noise which is easy repetitive and (usually) has a +10dB crest factor like compressed music?
Well to produce that dynamic signal in it's entirety without instantaneous clipping (inaudible as "clipping if short enough), the peaks can only be 100W so the average level can be no greater than 83dB. For music that has a 20 or 30dB crest factor, then take 10 and 20dB away from that max average SPL of 83dB.
The upside is unless clipping lasts long enough, it's not detectable as "clipping" BUT when one can switch back and forth between those peaks being clipped and reproduced, the subjective impression is it has more dynamic (as it does).
Remember the home hifi market is shaped by what people expect and have been marketed and a great deal is appearances and materials expectations.
Recording and playback rooms are a different set of needs, looks matter less, you MUST have the low end represented in proportion all the way down, in the home, that's usually a subwoofer added as a separate source to fill in what's missing (present in the signal but not reproduced).
Soffit mounted horns and direct radiating woofers were often used in studio's but then the lack of room interactions of meter bridge speakers became the thing as they preserved the stereo image better being simpler sources (part of the secret to speakers that disappear in the phantom image).
These are not home hifi speakers but the horns in this studio video are a 3 way speaker we make at work for recording studio's at home where above 250Hz a single 2 way synergy horn is a single source. ( The musicians were very happy with the album they recorded with the Baltic birch speakers, i was taken back by the video they made). These are about as small as i could make something that would do the whole signal albeit they use them at about 6 to 8 feet.
Tom Danley
https://www.youtube.com/watch?v=5NWp0BAG2ss
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Follow Ups
- RE: Dynamics - tomservo 04/5/2406:52:57 04/5/24 (2)
- RE: Dynamics - hahax@verizon.net 19:25:30 04/5/24 (1)
- RE: Dynamics - cawson@onetel.com 13:48:43 04/11/24 (0)
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