The compression ratio in the initial portion of a tapped horn does not make a lot of difference as far as "tuning". Keeping it high allows more path length in less cubic feet.
Too high of a compression ratio with too much power might tear up the cone.
looks good, and easy,
ill see if i can find a $120 driver somewhere with similar specs to replace the $300 one. 😛
ill see if i can find a $120 driver somewhere with similar specs to replace the $300 one. 😛
I ran a sim of that design. The Lab12 does stay within Xmax @400W. Did you measure Fb though? I expected the output @40 Hz to be a bit more than what you measured, if the Fb is indeed 36 Hz. Or maybe your measurements are showing the effects of vent compression.
The 16% distortion @50 Hz for the TH design is a bit of a curiousity, particularly as it appears to spike at that frequency - it's lower at nearby frequencies, and if it wasn't for that spike, the TH would look like the better performer. Panel flex perhaps? I ran into a similar issue when measuring distortion with my POC #2. Turned out to be a small stone below the box that was preventing the bottom from being in full contact with the ground.
Look in the SS15 thread for drivers that also work in the SS15, I think there is a dayton PA driver that sims similar.
Your Paypal in the form of a donation at the address of Don Snyder and this beautiful forum are more than welcome! 😀
is this
Dayton Audio PA380-8 15" Pro Woofer
an ok substitute for this in this horn?
specs look close
Eminence Kappalite 3015LF Neo 15" Driver
Dayton Audio PA380-8 15" Pro Woofer
an ok substitute for this in this horn?
specs look close
Eminence Kappalite 3015LF Neo 15" Driver
Thrift store score, parts/driver *blowse*
$7.50 🙂
http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=0NBTA5E9ZKDF5K2YRDJA
driver is a dvc 6.5" with a big capacitor and big coil thing + electronics.
ill probably only use the driver, if anyone has any interest in the rest you can pm me.
An externally hosted image should be here but it was not working when we last tested it.
$7.50 🙂
http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=0NBTA5E9ZKDF5K2YRDJA
driver is a dvc 6.5" with a big capacitor and big coil thing + electronics.
ill probably only use the driver, if anyone has any interest in the rest you can pm me.
Nice score.
If it's a powered speaker is there a reason you don't want to use the amp?
That big coil thing is a toroid. It's a type of transformer.
If it's a powered speaker is there a reason you don't want to use the amp?
That big coil thing is a toroid. It's a type of transformer.
it requires a special plug in multifunction cable that i cant seem to find/buy on the www, and reviews suggest the cable is prone to failure.
ive also heard blowse uses a lot of eq-ing in their subs.
im a pure-ist 🙂
i also cant seem to get it to work 😀 with my normal cables and wires.
ive also heard blowse uses a lot of eq-ing in their subs.
im a pure-ist 🙂
i also cant seem to get it to work 😀 with my normal cables and wires.
That's too bad. Can you contact a Bose dealer?
Yes, that's a trademark of their stuff.
Then put the woofer down and run far far away. Pure is not a word oft used in conjunction with Bose.
Another "feature" of Bose stuff.
You should be able to figure out how to bypass the input plug. Dual voice-coil + 2 sats means 4 amp channels & an XO. Some close-ups?
1st thing you do is check to see the config of the toroid... that is the single priciest part of a chip amp.
dave
1st thing you do is check to see the config of the toroid... that is the single priciest part of a chip amp.
dave
Spikes in a horns response will amplifiy distortion harmonics that fall in that range. Tapped horns almost always have a large spike in response at the 5th and 7th harmonics of the horn fundamental.
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oh, its a chip amp? thought it looked a bit weak/small.
ill take some close ups, but electronics is not my strong point.
ill take some close ups, but electronics is not my strong point.
It is likely a chip amp, but may not be... what i was suggesting that the toroid might be usable with a chipamp kit such as from chipamp.com or audiosector. Might be more effort than it is worth to use the existing amp for anything but parts.
dave
dave
I must admit to being skeptical of the results posted by weltersys, because they do not jive with what I've measured. It also doesn't fit the trends of measurements of similar subwoofer loudspeaker systems. Some are better than others, of course, but you can count on most to be in the same general scale, for similarly configured and sized devices with similar passbands and power handling capacity. For example, look at the measurement results of various subwoofer systems on the Home Theater forum:
I guess to be as open minded as I can be, I will just view at the weltersys data as having distortion figures that are about ~10dB lower than what I would expect. Maybe it is because of the two different methods we are using. Where he shows 5% (-25dB), for example, I will consider that to be roughly equivalent to what I might measure as around 15% (-15dB). That makes a sort of conversion factor between weltersys data and mine and other trends.
If I apply this conversion factor, his data makes sense to me. The BR values come in line, as do the TH levels, slightly higher because of the high-order spikes. Those always tend to bump up the THD.
From what I can see, weltersys was using a fixed sine through an amplifier, and probably the level was set with a meter. A microphone was positioned 2 meters away from the front baffle, and connected to an RTA. The fundamental and the lower harmonics appeared on the screen, which gave a visual indication of the relative SPL of the harmonics.
I was using an LMS 4.5 with the M51 calibrated precision microphone. The distortion measurements were done using a using a stepped sine, and the LMS system tracks the fundamental and bandstops it out, forming a THD+N chart. I always measure the noise floor, so any time the chart dips below that level, you don't know know what level is there, only that it was below the noise floor. That limits my view to about 1% THD, in this mode.
This is part of an overall test plan I often use that gets amplitude response, distortion, impulse/step response and sometimes polars (where required). In the case of many of the charts I've published, it was in connection with the 2005, 2006 and 2007 Prosound Shootouts. Several people were in attendance, including a representative of each company that manufactured or represents the device under test. That gives a little bit of warm fuzzy that the tests were unbiased and fair.
The goal was to see what the subs would do at high power levels, so a distance of 10 meters was chosen. The idea is to make sure not to overdrive the microphone, which is rated to 150dB. Safe margin there. It also helps reduce the source location distance error, i.e source at mouth or source at driver (usually a 2-3 meter difference there for horns and T-lines).
At high power levels, a reasonable S/N ratio is achieved, which allows THD measurement down to 1%. At the highest power levels, nothing gets below that. Some of the better speakers went below the noise floor on the 100 watt and 200 watt sweeps, but nothing does at the higher levels, so the 1% floor due to S/N was probably a reasonable limit. Certainly, at lower power levels, a closer distance could have been used, increasing S/N to get visibility into the lower distortion levels. But we were interested in high-power tests.
Beyond that, on a more personal level, I have put the LAB12 through its paces. I've measured on a baffle, in free air, in reflex boxes and in horns, with and without push-pull drive. I've done destructive testing of the LAB12, again, in several environments, both in free air and in systems. I've measured it in small signal mode (below a watt), and then at a lot of power levels, in 2v increments all the way up to levels far exceeding its thermal and mechanical limits.
In various loudspeaker systems, I've measured the LAB12 at 1 watt, 10 watts, 40 watts, 100 watts, 200 watts, 400 watts, 800 watts, 1000 watts and 1200 watts. I've measured it with swept sines that lasted only a few seconds, with MLS and other real-time signals, and with continuous sines (for power testing) that ran anywhere from a couple hours to a couple days. So I feel like I have a pretty good handle on that driver. I don't mean to be closed minded, but I do feel that I have what is probably the most complete picture of that driver I've seen anywhere. Much of this data is available on my website, in various references on the 12Pi hornsub page.
I guess to be as open minded as I can be, I will just view at the weltersys data as having distortion figures that are about ~10dB lower than what I would expect. Maybe it is because of the two different methods we are using. Where he shows 5% (-25dB), for example, I will consider that to be roughly equivalent to what I might measure as around 15% (-15dB). That makes a sort of conversion factor between weltersys data and mine and other trends.
If I apply this conversion factor, his data makes sense to me. The BR values come in line, as do the TH levels, slightly higher because of the high-order spikes. Those always tend to bump up the THD.
From what I can see, weltersys was using a fixed sine through an amplifier, and probably the level was set with a meter. A microphone was positioned 2 meters away from the front baffle, and connected to an RTA. The fundamental and the lower harmonics appeared on the screen, which gave a visual indication of the relative SPL of the harmonics.
I was using an LMS 4.5 with the M51 calibrated precision microphone. The distortion measurements were done using a using a stepped sine, and the LMS system tracks the fundamental and bandstops it out, forming a THD+N chart. I always measure the noise floor, so any time the chart dips below that level, you don't know know what level is there, only that it was below the noise floor. That limits my view to about 1% THD, in this mode.
This is part of an overall test plan I often use that gets amplitude response, distortion, impulse/step response and sometimes polars (where required). In the case of many of the charts I've published, it was in connection with the 2005, 2006 and 2007 Prosound Shootouts. Several people were in attendance, including a representative of each company that manufactured or represents the device under test. That gives a little bit of warm fuzzy that the tests were unbiased and fair.
The goal was to see what the subs would do at high power levels, so a distance of 10 meters was chosen. The idea is to make sure not to overdrive the microphone, which is rated to 150dB. Safe margin there. It also helps reduce the source location distance error, i.e source at mouth or source at driver (usually a 2-3 meter difference there for horns and T-lines).
At high power levels, a reasonable S/N ratio is achieved, which allows THD measurement down to 1%. At the highest power levels, nothing gets below that. Some of the better speakers went below the noise floor on the 100 watt and 200 watt sweeps, but nothing does at the higher levels, so the 1% floor due to S/N was probably a reasonable limit. Certainly, at lower power levels, a closer distance could have been used, increasing S/N to get visibility into the lower distortion levels. But we were interested in high-power tests.
Beyond that, on a more personal level, I have put the LAB12 through its paces. I've measured on a baffle, in free air, in reflex boxes and in horns, with and without push-pull drive. I've done destructive testing of the LAB12, again, in several environments, both in free air and in systems. I've measured it in small signal mode (below a watt), and then at a lot of power levels, in 2v increments all the way up to levels far exceeding its thermal and mechanical limits.
In various loudspeaker systems, I've measured the LAB12 at 1 watt, 10 watts, 40 watts, 100 watts, 200 watts, 400 watts, 800 watts, 1000 watts and 1200 watts. I've measured it with swept sines that lasted only a few seconds, with MLS and other real-time signals, and with continuous sines (for power testing) that ran anywhere from a couple hours to a couple days. So I feel like I have a pretty good handle on that driver. I don't mean to be closed minded, but I do feel that I have what is probably the most complete picture of that driver I've seen anywhere. Much of this data is available on my website, in various references on the 12Pi hornsub page.
Good point, and can be seen as a strike against THs unless those resonances are damped somehow.
It's also a good argument to aim for TH response curves like that of the SS15, which exhibits a lot less peaking.
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