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John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
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Old 29th September 2012, 01:23 AM   #27901
fas42 is offline fas42  Australia
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Originally Posted by Wavebourn View Post
Distortions, obviously.
I've just looked at the spec's and reviews of the subwoofer used, an EP600, flat response in an anechoic chamber to 19Hz, looks pretty impressive to me. How would you go one better?

Frank
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Old 29th September 2012, 01:34 AM   #27902
Wavebourn is offline Wavebourn  United States
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John Curl's Blowtorch preamplifier part II
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Originally Posted by fas42 View Post
I've just looked at the spec's and reviews of the subwoofer used, an EP600, flat response in an anechoic chamber to 19Hz, looks pretty impressive to me. How would you go one better?
Probably with something with less excursion needed than for a single 12" driver. I have a pair of 12" drivers in a concrete horn under my floor, but watching movies anyway I hear them when they suppose to cause shaking of stomachs and sofas only. It is not the problem to get something down to 19 Hertz and below. The problem is to get it with low distortions.
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Old 29th September 2012, 01:54 AM   #27903
Kindhornman is offline Kindhornman  United States
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John Curl's Blowtorch preamplifier part II
Wavebourne,
So are you saying that you hear the 12" cones mechanically or in distortion mode?
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Old 29th September 2012, 01:59 AM   #27904
fas42 is offline fas42  Australia
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Originally Posted by Wavebourn View Post
It is not the problem to get something down to 19 Hertz and below. The problem is to get it with low distortions.
Agreed, achieving truly low distortion bass is a difficult exercise. But, in the context of that listening test if those speakers were producing excess distortion then the results would have been skewed to make the distortion per frequency slope less extreme than it came out. They found the higher the frequency, harmonics, the easier it was for the subjects to pick that something was out of kilter, so if the subwoofer was producing excess distortion they wouldn't have needed to run it at volumes louder than the music for a difference to be heard ...

Frank

Last edited by fas42; 29th September 2012 at 02:01 AM.
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Old 29th September 2012, 02:03 AM   #27905
Wavebourn is offline Wavebourn  United States
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John Curl's Blowtorch preamplifier part II
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Wavebourne,
So are you saying that you hear the 12" cones mechanically or in distortion mode?
I am saying that I hear pair of 12" in concrete horn when they produce something on about 10 Hz frequency. If I hear them I obviously hear distortions.
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Old 29th September 2012, 02:08 AM   #27906
Kindhornman is offline Kindhornman  United States
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John Curl's Blowtorch preamplifier part II
Wavebourne,
At anything like that low frequency of 10hz I would expect you would unless your whole room and more was the mouth of the waveguide. I can't imagine anyone having the room for even a 25hz mouth size, that is gigantic at 1/4 wavelength. I would expect the 12" to rattle fairly hard at that frequency.
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Old 29th September 2012, 02:29 AM   #27907
Wavebourn is offline Wavebourn  United States
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John Curl's Blowtorch preamplifier part II
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Wavebourne,
At anything like that low frequency of 10hz I would expect you would unless your whole room and more was the mouth of the waveguide. I can't imagine anyone having the room for even a 25hz mouth size, that is gigantic at 1/4 wavelength. I would expect the 12" to rattle fairly hard at that frequency.
Rattling in the room is rattling in the room, it is no problem to tell the difference. However, when I covered the opening by fabric to protect it from dust and garbage I heard rattling of the fabric. But if I hear distortions I hear distortions.

It was only an example. I did not want to complain that my system is bad. What I mean, it is hard to get low distortions on low frequencies, especially from a single 12" driver in a wooden bass reflex enclosure.
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Old 29th September 2012, 03:08 AM   #27908
RNMarsh is offline RNMarsh  United States
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John Curl's Blowtorch preamplifier part II
It is very hard to get low distortion in the bass/deep bass and do it at high spl needed for hearing it as being loud. I have to use 4 - high effeciency 15 inch bass drivers which can handle high power as well. And, I dont think it is the greatest. But compared to a two way it is great. but compared to real sounds, it still is marginal. So I picked up a pair of 18 inch subs to make enclosures and crossovers (active) for. This system will produce prodigous output at very low freqs and do it accurately. It takes a large total radiating cone area to do this right or big horns.
There are quit a few very low freqs recorded on music CD and movie DVD. Many bass players now also play a 5 sting bass as opposed to standard 4 string (40Hz). The 5-string bass is subterranion. Try to hear the powerful first two notes of the opening of Chris Isaak "Baby Did a Bad, Bad Thing' from "Best of Chris Isaak" (remastered). -RNM

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Old 29th September 2012, 03:10 AM   #27909
Kindhornman is offline Kindhornman  United States
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John Curl's Blowtorch preamplifier part II
Okay Wavebourn,
I thought that you had the two 12's on a horn per side, not a BR enclosure. Never mind....
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Old 29th September 2012, 02:50 PM   #27910
john curl is offline john curl  United States
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I must admit that Wavebourn has a better subwolfer than I have. My problem is that I live in an apartment, and I have neighbors. There is no way that I can generate 'gut pushing' bass, and still remain a tenant, so it is a moot point.
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