Zilch's AK Design Collaborative - Econowave Speaker
- Thread starter Zilch
- Start date
Hard to say without any porting or tuning of the low end enclosure. Overall I dig what I'm hearing and was happy it worked the first time
.Edit: I've been running the system for a while now and find that the low end is a bit better than first thought. Once these boxes get tuned correctly this is gonna be a monster set of speakers. I may be selling some others soon
Paratima
E'Wavin'
Thank you, Kegger :ntwrthy: JackGiff :ntwrthy: Zilch :ntwrthy: and anyone else in there that I may have missed.
Lets hope these explanations clear it all up. Maybe one of us could summarize this and include a note somewhere in the base notes / diagrams / instructions so future E'Wavers won't get confused all over again. I have no idea whether "absolute polarity" is a real thing, I just want to get the dang wires on right. I lucked out. It seems I mis-interpreted Jack's original PM and still got the wires hooked up correctly. Both my wire sets were 180 degrees out = all OK. Ran a curve on my ZLH's & got no dropout at crossover.
All's well that ends well. Thanks again to everyone for helping out. What a great place AK is!
Lets hope these explanations clear it all up. Maybe one of us could summarize this and include a note somewhere in the base notes / diagrams / instructions so future E'Wavers won't get confused all over again. I have no idea whether "absolute polarity" is a real thing, I just want to get the dang wires on right. I lucked out. It seems I mis-interpreted Jack's original PM and still got the wires hooked up correctly. Both my wire sets were 180 degrees out = all OK. Ran a curve on my ZLH's & got no dropout at crossover.
All's well that ends well. Thanks again to everyone for helping out. What a great place AK is!
Russellc
Addicted Member
Hard to say without any porting or tuning of the low end enclosure. Overall I dig what I'm hearing and was happy it worked the first time
Edit: I've been running the system for a while now and find that the low end is a bit better than first thought. Once these boxes get tuned correctly this is gonna be a monster set of speakers. I may be selling some others soon
Great. Glad to hear I didnt mis-lead you, I was sure you'd like. I believe we are the only 2 from Jays shindig that are E'waving. At the next meet, we'll have to demonstrate E'wave. I've been trying to get Jay to listen to them for a while, but holidays are busy times, maybe now that can get accomplished. We really need to get that midwest audio club thing going!:thmbsp:
Russellc
most speakers have non-symmetric bl and tend to be a little stronger on outward drive, so an impulse response with polarity reversed will produce a different sound. as to whether this is audible, who knows...who cares.
I'll second that.
I'm thinking once I get this box tuned or move onto something better I'm going to be a very happy guy.
If all goes well the next KC meet should only be about 3 months off.
Rex, you could tune the box by ears. Do as Zilch suggested in order to fit a length of plastic pipe in there. I used to use the paper rolls from fabric or drafting paper rolls. You could use a longer length such as 10-12" at first and if the bass is not right, cut of an inch or 2 and try again. I think you know how drums are supposed to sound much more so than many of us here.
Also, IIRC, the Model 14 woofer is not really considered high-efficiency so there's a chance that you might need to change the crossover to the normal efficiency version.
Also, IIRC, the Model 14 woofer is not really considered high-efficiency so there's a chance that you might need to change the crossover to the normal efficiency version.
hey folks, given that there is a lot of discussion about the suitability of various woofers to pair up with econowave and this inevitably leads to looking at distortion measurements, i thought that i would conduct a little experiment in order to see how much distortion would actually be audible.
design
fundamental is sine wave at 261.626hz, which is the frequency of middle c on piano. i chose this frequency because it has harmonics that run right through the midrange, which is where our ears tend to be most sensitive to distortion.
second harmonic is 523.252hz
third harmonic is 784.878hz
fifth harmonic is 1308.130hz
the program i used was audacity
tones were played over sony headphones
my best guess for fundamental level spl is about 80db or so
i claim not to be a golden ear and i surely have some hearing damage. i can hear from about 18hz to 17khz on the test headphones (i'm not sure if the bounds are determined by my ears or the headphones).
test of audibility of second harmonic
subjective analysis:
-0db 100% distortion; clearly audible, distortion sound overwhelms the fundamental
-10db, 30% distortion; still clearly audible, distortion sounds about even with fundamental
-20db, 10% distortion; low enough that if i wasn't listening for it, i could miss it, however a/b switching reveals it easily
-30db, 3% distortion; i can only hear a difference when focusing very, very hard in an a/b switching.
-36db (as low as audacity can decrease spl), 1.6% distortion; i 'think' i might here something, but i'd probably fail a blind a-b test, so i'm calling this level inaudible.
test of audibility of third harmonic
subjective analysis:
-0db 100% distortion; clearly audible, distortion sound overwhelms the fundamental
-10db, 30% distortion; still clearly audible, distortion sounds about even with fundamental
-20db, 10% distortion; unlike the second harmonic, third harmonic still audible at this level. tone sounds "wrong" like an annoying buzz.
-30db, 3% distortion; this is sort of like the experience with 10% distortion on the second fundamental, if i was not listening for it, i could miss it. however, it is there in a/b switching, but i have to be focusing to hear it.
-36db (as low as audacity can decrease spl), 1.6% distortion; i can hear this only when focusing very closely in a-b switching. if blinded, i think that i would fail to hear the tone as it is removed, but i suspect that i could pick it up when it is added.
test of audibility of fifth harmonic
subjective analysis:
-0db 100% distortion; clearly audible, distortion sound overwhelms the fundamental
-10db, 30% distortion; still clearly audible, distortion sounds about even with fundamental
-20db, 10% distortion; as with third harmonic, fifth harmonic still audible at this level. tone sounds "wrong" like an annoying buzz. subjectively, it is worse then the third and *much* worse than the second; when played by itself, the tone sound smooth, just at a higher frequency, but in combination with the fundamental, the sound turns very harsh.
-30db, 3% distortion; still audible even without a-b switching.
-36db (as low as audacity can decrease spl), 1.6% distortion; at this level it is audible even without a-b switching.
back in business...
i created a second fifth harmonic distortion, but at 10% of power, this has the effect of reducing the level by 20db, so i can test further down than -36db. as a check i played the third harmonic which was created at 100% power at -20db, and it is the same subjective spl as the 10% power tone, played at 0db.
-40db, 1% distortion, if you know what you are listening for, it can be heard without a-b, also a-b reveals it pretty easily
-50db, 0.3% distortion, i can barely hear it, but it's there in a-b comparison.
-56db, 0.16% distortion, i can just barely hear it in a-b comparison. however, at -56db, i can just barely heat it even without playing the fundamental tone.
my conclusion is that similar to other reports, second harmonic distortion is not as bad as the third and certainly no where near as bad as fifth. i wouldn't be surprised if music masks distortion by 10db or more, so that should be considered. in other words, 3% second harmonic distortion is barely audible in this experiment, so a woofer with 10% second harmonic distortion would probably be okay, even though that seems like a lot of distortion. for third harmonic distortion, i would look for about 10db lower distortion than the second fundamental as the maximum. so, for test tones, i would want to keep 3rd harmonic distortion to about 2% or so, and with a 10db masking effect in music, 5% is probably about where third harmonic distortion starts to become audible.
it's too bad that most companies don't report fifth harmonic distortion. in this experiment, it was by far the greatest offender, being audible down to below -50db. i would like to see a driver with less than 0.3% fifth harmonic distortion for test tones and with 10db of masking, i think 1% would be the level where it would become audible.
design
fundamental is sine wave at 261.626hz, which is the frequency of middle c on piano. i chose this frequency because it has harmonics that run right through the midrange, which is where our ears tend to be most sensitive to distortion.
second harmonic is 523.252hz
third harmonic is 784.878hz
fifth harmonic is 1308.130hz
the program i used was audacity
tones were played over sony headphones
my best guess for fundamental level spl is about 80db or so
i claim not to be a golden ear and i surely have some hearing damage. i can hear from about 18hz to 17khz on the test headphones (i'm not sure if the bounds are determined by my ears or the headphones).
test of audibility of second harmonic
subjective analysis:
-0db 100% distortion; clearly audible, distortion sound overwhelms the fundamental
-10db, 30% distortion; still clearly audible, distortion sounds about even with fundamental
-20db, 10% distortion; low enough that if i wasn't listening for it, i could miss it, however a/b switching reveals it easily
-30db, 3% distortion; i can only hear a difference when focusing very, very hard in an a/b switching.
-36db (as low as audacity can decrease spl), 1.6% distortion; i 'think' i might here something, but i'd probably fail a blind a-b test, so i'm calling this level inaudible.
test of audibility of third harmonic
subjective analysis:
-0db 100% distortion; clearly audible, distortion sound overwhelms the fundamental
-10db, 30% distortion; still clearly audible, distortion sounds about even with fundamental
-20db, 10% distortion; unlike the second harmonic, third harmonic still audible at this level. tone sounds "wrong" like an annoying buzz.
-30db, 3% distortion; this is sort of like the experience with 10% distortion on the second fundamental, if i was not listening for it, i could miss it. however, it is there in a/b switching, but i have to be focusing to hear it.
-36db (as low as audacity can decrease spl), 1.6% distortion; i can hear this only when focusing very closely in a-b switching. if blinded, i think that i would fail to hear the tone as it is removed, but i suspect that i could pick it up when it is added.
test of audibility of fifth harmonic
subjective analysis:
-0db 100% distortion; clearly audible, distortion sound overwhelms the fundamental
-10db, 30% distortion; still clearly audible, distortion sounds about even with fundamental
-20db, 10% distortion; as with third harmonic, fifth harmonic still audible at this level. tone sounds "wrong" like an annoying buzz. subjectively, it is worse then the third and *much* worse than the second; when played by itself, the tone sound smooth, just at a higher frequency, but in combination with the fundamental, the sound turns very harsh.
-30db, 3% distortion; still audible even without a-b switching.
-36db (as low as audacity can decrease spl), 1.6% distortion; at this level it is audible even without a-b switching.
back in business...
i created a second fifth harmonic distortion, but at 10% of power, this has the effect of reducing the level by 20db, so i can test further down than -36db. as a check i played the third harmonic which was created at 100% power at -20db, and it is the same subjective spl as the 10% power tone, played at 0db.
-40db, 1% distortion, if you know what you are listening for, it can be heard without a-b, also a-b reveals it pretty easily
-50db, 0.3% distortion, i can barely hear it, but it's there in a-b comparison.
-56db, 0.16% distortion, i can just barely hear it in a-b comparison. however, at -56db, i can just barely heat it even without playing the fundamental tone.
my conclusion is that similar to other reports, second harmonic distortion is not as bad as the third and certainly no where near as bad as fifth. i wouldn't be surprised if music masks distortion by 10db or more, so that should be considered. in other words, 3% second harmonic distortion is barely audible in this experiment, so a woofer with 10% second harmonic distortion would probably be okay, even though that seems like a lot of distortion. for third harmonic distortion, i would look for about 10db lower distortion than the second fundamental as the maximum. so, for test tones, i would want to keep 3rd harmonic distortion to about 2% or so, and with a 10db masking effect in music, 5% is probably about where third harmonic distortion starts to become audible.
it's too bad that most companies don't report fifth harmonic distortion. in this experiment, it was by far the greatest offender, being audible down to below -50db. i would like to see a driver with less than 0.3% fifth harmonic distortion for test tones and with 10db of masking, i think 1% would be the level where it would become audible.
Clmrt
Just thrilled.
A little redneck assembly later...
Attachments
Sorry, it's been a few pages ago, but I have a WT3 that I could send out for you to get readings..
Glad you're diggin' them!
Now you're going to make me build a pair of Jensen Imperial cabs, aren't you??:yes:
Richard C.
Active Member
Here are the Altec Model 14 woofer specs...
Rex Everything and Zilch:
I was away from this thread for a few days, so I didn't post this sooner.
From WooferTester II.
I tested a nice example with a fresh surround, from Bill H. in Great Plains Audio. I would post the actual plot, but it's on a PC that doesn't want to bootup, today. (1st time ever!):tears:
Fs = 22.4 Hz
Qes = .1569
Qms = 6.8436
Qts = .1534
Zmax = 261.65 ohms
Le = 2.1394 mH
Vas = 380.0205 L (13.42 ft^3
Diam = 254. mm
BL = 15.8724 N/A
Cms = 1053.8339 um/N
Kms = 948.9162 N/m
Mms = 47.8789 g
Sens = 96.194 dB@1W/1m
Eff = 2.6266 %
Rms = .9849 ohms
The port is exactly the same on the Model 14 and the 9842: 2" x 4" x 3/4" which is tuned to ~38.5 Hz according to BassBox 6. (3.75 ft^3)
Richard C.
Rex Everything and Zilch:
I was away from this thread for a few days, so I didn't post this sooner.
From WooferTester II.
I tested a nice example with a fresh surround, from Bill H. in Great Plains Audio. I would post the actual plot, but it's on a PC that doesn't want to bootup, today. (1st time ever!):tears:
Fs = 22.4 Hz
Qes = .1569
Qms = 6.8436
Qts = .1534
Zmax = 261.65 ohms
Le = 2.1394 mH
Vas = 380.0205 L (13.42 ft^3
Diam = 254. mm
BL = 15.8724 N/A
Cms = 1053.8339 um/N
Kms = 948.9162 N/m
Mms = 47.8789 g
Sens = 96.194 dB@1W/1m
Eff = 2.6266 %
Rms = .9849 ohms
The port is exactly the same on the Model 14 and the 9842: 2" x 4" x 3/4" which is tuned to ~38.5 Hz according to BassBox 6. (3.75 ft^3)
Richard C.
Whoa, THANKS, Richard! That substantially simplifies this tuning exercise.
All we need now are the precise internal dimensions of Rex Everything's enclosures.... :guitar:
You guys are keeping me busy updating the "Official E'Waver" list.
Good job on your Large Advent upgrade project, Huck! :thmbsp:
[New Advent Utility, no?
]130030/3451=37.6789
Russellc
Addicted Member
I'll second that.
I'm thinking once I get this box tuned or move onto something better I'm going to be a very happy guy.
If all goes well the next KC meet should only be about 3 months off.
Good news, I'd hate to have to wait all the way to summer!
Russellc
Russellc
Addicted Member
Rex Everything, here's your chance to measure that altec driver and tell us ALL what the unknowns are! I say go for it!
Russellc
WOW! Thanks so much Richard C.
Zilch, I'll go pull the woofer and measure the internals of the madrid box.