Oliver,
No, I have not measured the distortion of the DSL TH-118, but have measured the distortion of my Keystone sub using a BC18SW115-4, which has nearly the same frequency and phase response of the DSL TH-118. I would expect them to have similar distortion, loaded with the same drivers.
You simulations show a single 15" TH of 379L and a BR of 90L, my compact sub uses 2 x 15" in a net 77L chamber.
I would expect the much larger enclosures to have less distortion for a given SPL output, and a TH of the same size as the PPSL "ShoeHorn" to have more distortion.
Art
Josh Ricci has tested a wider variety of subs for output and distortion, his website is a treasure trove of comparative information:
Data-Bass
All the designs I have tested are primarily for PA use, since no one likes to lug around more cabinets than needed, usually PA subs are used near their limits, so I have never bothered with one watt measurements, but one can assume distortion would be far less than my tests carried out at (or above) full rated power.
The tests include a variety of speakers, used in both TH and BR, (examples of the actual measurements are in the OP) and although the larger TH have as much as six dB more output, the distortion has always been higher than a BR with the equivalent SPL, so a pair of the BR would have similar output but lower distortion.
As you can see below, the B&C18SW115-4 output goes up around 6 dB from the BR to the Keystone TH, and distortion almost exactly doubles, though to tell the truth, I can't hear the difference between 2.7 % and 5.4% distortion. When <100 Hz distortion gets above around 10%, it may start to impinge on the quality of "clean" music sources.
Art
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Ahhh, Mr. McBean, I had my yearly physical last week, and my doctor definitely wasn't confused. HaHa, he is actually a friend of mine, the poor guy. And the way he examined my PROSTATE I would have noticed even if I was PROSTRATE!
My typo was probably due to my impeding arthritis, which is getting increasingly ridiculous. I am due to retire this year and finally "enjoy" life, but now I am worried I will get shipped off to an old folks home and left to slowly rot away.
By the way, I am really surprised how my "older men" there are here in this forum. When I first came here I just assumed it was a bunch of teenage bass hungry homeboys with there there pants falling off their ***** and their baseball caps on backwards, blasting rap music.
So Gentlemen, I hereby propose we develop a "subwoofer therapy" technique to heals all our ills. We need to find some way to incorporate low frequency vibrations into a new health craze. Then we can make tons of $$$ making custom subwoofers that can cure any ill - the new miracle health cure!!!!
Weltersys,
Thanks for the info on distortion and link - I have seen that already and wondered of there were other studies.
So keeping distortion below 10% when at max SPL is considered acceptable then? When listening to subs at home for instance where you do not max out SPL what kind of HD levels are considered good in the bass region for hifi? Are people looking for sub 1% distortion at average SPL's of under 85 dB? Is there an audible improvement from 3% to sub 1% distortion or is it not worth pursuing in a sub?
Thanks for the info on distortion and link - I have seen that already and wondered of there were other studies.
So keeping distortion below 10% when at max SPL is considered acceptable then? When listening to subs at home for instance where you do not max out SPL what kind of HD levels are considered good in the bass region for hifi? Are people looking for sub 1% distortion at average SPL's of under 85 dB? Is there an audible improvement from 3% to sub 1% distortion or is it not worth pursuing in a sub?
Hi Y'all,
Just a quick follow-up on my medical situation: the external plastic plumbing is gone, and all the cancer is gone, none in the extracted tissue or lymph nodes, none in the surgical margins, none in the bone scan. so it looks like it was prudent to take rapid and radical action. Don't let anyone talk you into bypassing PSA tests or check-ups.
Thanks for all the good wishes.
Regards,
Just a quick follow-up on my medical situation: the external plastic plumbing is gone, and all the cancer is gone, none in the extracted tissue or lymph nodes, none in the surgical margins, none in the bone scan. so it looks like it was prudent to take rapid and radical action. Don't let anyone talk you into bypassing PSA tests or check-ups.
Thanks for all the good wishes.
Regards,
1. Since with most music sources I find it hard to detect less than 10% harmonic distortion (harmonics 20 dB lower than the fundamental), I consider less than 10% THD "acceptable".
2. THD levels that do not materially change the music presentation would probably be considered good by most listeners, who would probably be surprised at the level of distortion they find OK.
3. I don't know what other people are looking for, but most don't seem to write much about distortion. At very low frequencies, and low SPL, 1% (harmonics 40 dB down from the fundamental) distortion could be detectable in some circumstances, for instance if a 20 Hz sine wave is played at 85 dB,(a level so low it is near the threshold of audibility for most people) and it generates a -40 dB 5th harmonic (100 Hz), the harmonic would be perceived by most as sounding only 5 dB lower in level, sounding more than half as loud. However, in most bass musical instruments, harmonics are higher in level than the fundamental tone, so speaker distortion often can be hard to distinguish from the instrument's existing overtone structure. That said, even order distortion, being octaves, does not change the musical composition regardless of level, but odd order distortion can create notes that musically alter the composition, so can be more easily detected.
4. I would suggest comparing the two and deciding for yourself, but for me a reduction from 3% to 1% distortion would probably not be audible even in an A/B test with any musical source I'd be inclined to listen to.
Art
Hi xrk971,
Thanks.
Art is correct it does come down to individual preference. I don't have any data on the subject, but I'm willing to bet that most people have no idea about the amount of distortion that used to be contained in music that was captured e.g.: in recording and reproducing a vinyl record. 10% distortion in the bass region does not sound like a lot.
Regards,
Thanks.
Art is correct it does come down to individual preference. I don't have any data on the subject, but I'm willing to bet that most people have no idea about the amount of distortion that used to be contained in music that was captured e.g.: in recording and reproducing a vinyl record. 10% distortion in the bass region does not sound like a lot.
Regards,
I think it is interesting how accustomed we are to hearing distortion and accepting that is part of the sound. I have a speaker that has 0.5% distortion or less from 50Hz on up and it sounds like a different recording because we are so used to normal speakers with more distortion in the bass region.
Turn up the volume, and the 0.5% distortion will increase to the level of "normal" speakers
. Distortion figures without SPL and measurement distance are useless, it is not hard to find "normal" speakers with less than 0.5% distortion from 50 Hz up if they are played at "normal" (clock radio
) levels.Our hearing is progressively less sensitive to SPL in the octaves below 50 Hz, getting loud and clean (like 20 Hz >110 dB SPL at two meters) down low does not come cheaply or in small boxes.
Hi Y'all,
Here are some links to test files that can come in handy:
Sound Tests and Audio Test Tones
Low Frequency Harmonic Distortion Subwoofer Sound Test
The Ultimate Bass Test | Ultra Low Frequency Range Test
Sine Burst Tones (20-200 Hz)
Regards,
Here are some links to test files that can come in handy:
Sound Tests and Audio Test Tones
Low Frequency Harmonic Distortion Subwoofer Sound Test
The Ultimate Bass Test | Ultra Low Frequency Range Test
Sine Burst Tones (20-200 Hz)
Regards,
It was at 85 dB at 2 m quite a bit louder than a clock radio
I'd expect just about any decent subwoofer to have very low distortion at 91 db 1 meter above 50 hz....
The PPSL ShoeHorn (not very efficient, but small for a PA sub capable of over 130 dB measured output at 1m) does 85 dB at 2 meters at 50 Hz outdoors with one watt, I tested it at about 1000 and 2200 watts, power levels in line for it's intended use.It was at 85 dB at 2 m quite a bit louder than a clock radio
Just checked my Grundig Yacht Boy 400PE clock radio in the kitchen, it does 82 dBC at 2 meters, though it sounds gnarly at that level. My voice (no amplification) can do about 105 dBC at two meters, it would sound over four times as loud as your sub
.Art
Oliver,
From the above link:
"The bottom row (10-20 Hz) consists of frequencies that are below the human hearing range (infrasound). Ideally, these frequencies should remain inaudible. Outstanding subwoofers coupled with excellent hearing will reach 18 Hz maybe 16Hz, but never 10 Hz. 10 Hz is located one octave below our lowest limit: there is no way humans can hear such a frequency."
The author evidently has never listened to a decent set of headphones or a sub that can do more than 85 dB
.I wish I could still hear 4000 Hz louder than I hear 16 Hz
...Art
Oliver,
I wish I could still hear 4000 Hz louder than I hear 16 Hz
Art
nahhhh, you never wanted 4khz anyways... its like built in eq!
Hi Art,
I never had good low frequency hearing, and most people I have known don't either. It's a real gift to be able to hear 16Hz or so. I used to have two 2'x2'x2' cubes stuffed w/ 4x10" ea., and both of those on top of each other in a corner were not audible to me @ 20Hz even when the walls were literally shaking (I could hear the walls). Nowadays I don't have any use for extreme lows or extreme levels, but it's fun to see what can be done now.
Regards,
I never had good low frequency hearing, and most people I have known don't either. It's a real gift to be able to hear 16Hz or so. I used to have two 2'x2'x2' cubes stuffed w/ 4x10" ea., and both of those on top of each other in a corner were not audible to me @ 20Hz even when the walls were literally shaking (I could hear the walls
). Nowadays I don't have any use for extreme lows or extreme levels, but it's fun to see what can be done now.Regards,
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