Try to avoid total failure before hand
Hi,
Given they may not totally suited for dipoles, but will the 4 of them drivers at least has half a chance to be in 2 dipoles with 2 drivers in series for 8 ohm? I would like to force them to handle up to 70 to 80hz or so with active filtering.
Power==175W RMS
PEAK==350WATT
Imp==4 ohm
RDC==2.8 ohm
Fs==25Hz
Qes==0.62
Qms==2.9
Qts==0.51
Vas==248L(8.75cu.ft.)
Xmas==+/-6mm(0.24”)
Travel==1.1”
No%==0.627
BI=6.8TM
Mms==64G
Sd sq.M.==0.0531
MAGNET==56oz
SIZE==12”
Features
2" 2 layer voice-coil on aluminum bobbin
chrome ion deposited polypropylene cone with stress relief rings
Rubber surround
Regards,
Chris
Hi,
Given they may not totally suited for dipoles, but will the 4 of them drivers at least has half a chance to be in 2 dipoles with 2 drivers in series for 8 ohm? I would like to force them to handle up to 70 to 80hz or so with active filtering.
Power==175W RMS
PEAK==350WATT
Imp==4 ohm
RDC==2.8 ohm
Fs==25Hz
Qes==0.62
Qms==2.9
Qts==0.51
Vas==248L(8.75cu.ft.)
Xmas==+/-6mm(0.24”)
Travel==1.1”
No%==0.627
BI=6.8TM
Mms==64G
Sd sq.M.==0.0531
MAGNET==56oz
SIZE==12”
Features
2" 2 layer voice-coil on aluminum bobbin
chrome ion deposited polypropylene cone with stress relief rings
Rubber surround
Regards,
Chris
Re: Try to avoid total failure before hand
Given those specs, you should befine using them in a dipole. However, since the Qts falls a tad bit short, you may find the need to use a little EQ'ing.
😉
chris ma said:
Given those specs, you should befine using them in a dipole. However, since the Qts falls a tad bit short, you may find the need to use a little EQ'ing.
😉
Just jumping in at the end of this long and good thread, but efficiency doesn't matter in terms of depth or volume.
And in a sense, the Qts doesn't matter. If you have high Qts drivers you may not need active EQ, as you've found, although you may up higher. A low Qts driver, as the Peerless users have found, will need more EQ. But that's just to get flat response. An efficient driver will simply require less amplification, as will a driver that needs less EQ.
The speaker itself doesn't care.
In absolute terms you still need a certain amount of displacement for a certain volume.
If the drivers you currently use provide what you need, that's great. But if you like louder low bass you are going to need either bigger drivers, or smaller drivers with longer Xmax.
Or a wider baffle.
Cheers
And in a sense, the Qts doesn't matter. If you have high Qts drivers you may not need active EQ, as you've found, although you may up higher. A low Qts driver, as the Peerless users have found, will need more EQ. But that's just to get flat response. An efficient driver will simply require less amplification, as will a driver that needs less EQ.
The speaker itself doesn't care.
In absolute terms you still need a certain amount of displacement for a certain volume.
If the drivers you currently use provide what you need, that's great. But if you like louder low bass you are going to need either bigger drivers, or smaller drivers with longer Xmax.
Or a wider baffle.
Cheers
sfdoddsy said:
Hate to say it, but that's not nessisarily true.
My current driver choice and baffle size is more than enough to play as loud and as low as anyone might want. I tend to play my system very very loud, and not once have these subs ever fallen short. I've played many music CDs with heavy bass in them at volumes so high, you can feel the bass all the way out in my driveway. I've played DVD movies like "Lord of the Ring" and other great box office hits that have such extremely low bass content, everything in the house rattles like crazy.
Still, at these volume levels, these drivers have never bottomed out, distorted, or started compressing under any amount of time or anything.
Has anyone here ever heard the Sunfire Subwoofers in person? Just imagine putting about 3 or 4 of those in your listening room full blast, and that's what you get with my subs with the added bonus of being completely tunefull and musical without any boom at all.
My point was that the efficiency and Q effect how much amplifier power and EQ you might need, not the absolute level bass, which is a function of driver size, xmax and baffle width.
Your twin 15s should provide slightly more bass at 20Hz than my twin 12s do.
Steve
Your twin 15s should provide slightly more bass at 20Hz than my twin 12s do.
Steve
sfdoddsy said:
I just wish there was some way I could measure my dipoles and get some graphs like the ones of yours on your site.
I would really like to see the exact in-room responce of these babies. 😉
If you have an RS meter, just download the free demo of ETF from www.etfacoustic.com . It has a correction file for the meter. A proper mic would be even better such as the Behringer ECM8000.
Steve
Steve
I do have a digital RS meter. But don't they loose sensitivity below a certain frequency? I heard they only "hear" down to something in the 30-40Hz range...
They start to roll off in the bass (and the treble) but a compensation file in ETF corrects for this. As I said, a proper mic would be better, but if you have the RS meter and download ETF it won't cost you anything.
There is a bit of a learning curve, but it is not too bad.
You won't be able to print out or save the results, but you can use Print Screen to do screen dumps.
Steve
There is a bit of a learning curve, but it is not too bad.
You won't be able to print out or save the results, but you can use Print Screen to do screen dumps.
Steve
I just remembered, I have a couple of Sure SM81-LC mics sitting around and a dbx mic preamp with 49 volt phantom power!!
If it's possible, can I use that setup with my computer?
My soundcard is a SoundBlaster Audigy2 with the front mounted break-out box. I use the fiber optic output for playing mp3's through my system. I assume I can use it as is.
Any thought?
Thanks in advance!! 😀
If it's possible, can I use that setup with my computer?
My soundcard is a SoundBlaster Audigy2 with the front mounted break-out box. I use the fiber optic output for playing mp3's through my system. I assume I can use it as is.
Any thought?
Thanks in advance!! 😀
All you need is a full duplex sound with ins and outs, which I assume the Audigy is. You use one output channel to play tones through your system and one input channel from your mic preamp.
The other out and in channel are used to play a check tone through the soundcard to calibrate.
Just check the ETF site and it will explain all.
The demo lets you do two tests at a time, then you have to start open the program again ut it isn't too much of a hassle.
If the Shure mics are of reasonable quality you should be fine.
And test one speaker at a time.
Cheers
Steve
The other out and in channel are used to play a check tone through the soundcard to calibrate.
Just check the ETF site and it will explain all.
The demo lets you do two tests at a time, then you have to start open the program again ut it isn't too much of a hassle.
If the Shure mics are of reasonable quality you should be fine.
And test one speaker at a time.
Cheers
Steve
chops said:
As far as i can see, Shure SM81-LC is a cardioid microphone. You should not use cardioid mics for measurement purposes. In short this is because cardioid microphones do not measure sound pressure only. This leads to a proximity effect (bass boost) which cannot be compensated for, reliably.
I had a presentation about this last summer on a conference for voice scientists.
http://www.speech.kth.se/~svante/pevoc5/GranqvistMicrophonesWorkshopPevoc5.ppt
Look for an omnidirectional mic instead, you can find good electret omnis for less than $30.
I think I have a couple of them hanging around, too. I'm not going to worry about it right now though.
I just pulled everything out of my old computer case and reinstalled all of it in a large server tower. Now for some reason, the sound card isn't working. I'll have to play around with it some tomorrow when I take some breaks from working on my new Linux site. 😀
I just pulled everything out of my old computer case and reinstalled all of it in a large server tower. Now for some reason, the sound card isn't working. I'll have to play around with it some tomorrow when I take some breaks from working on my new Linux site. 😀
W Baffle Dipole Sube w/PPA15s
I bough a quad of Pyle PPA15s to build a pair of W baffle subs (scaled up version of Linkwitz's Phoenix sub) and a pair of the Parts Express 250W subs amps (the ones with the bass boost capabiity). I've only completed one, but I'm very impressed by the sound quality & quantity. I've got the sub amps running flat right now (they come that way according to the docs) and the bass extension is quite good. I was a little dissapointed in the PPA15 build quality, I've never seen such a flimsy basket, even on much smaller drivers. Also, mine had spade terminals rather than the fancy gold binding posts that Chops got on his, but I think I prefer that, kinda hard to solder to a binding post😉
I was surprised how well they integrated with a full horn system...
After I get the second one built, I'm gonna put my Altec 755Es on open baffles, and see how a complete open baffle system sounds in my room...
Peace
I bough a quad of Pyle PPA15s to build a pair of W baffle subs (scaled up version of Linkwitz's Phoenix sub) and a pair of the Parts Express 250W subs amps (the ones with the bass boost capabiity). I've only completed one, but I'm very impressed by the sound quality & quantity. I've got the sub amps running flat right now (they come that way according to the docs) and the bass extension is quite good. I was a little dissapointed in the PPA15 build quality, I've never seen such a flimsy basket, even on much smaller drivers. Also, mine had spade terminals rather than the fancy gold binding posts that Chops got on his, but I think I prefer that, kinda hard to solder to a binding post😉
I was surprised how well they integrated with a full horn system...
After I get the second one built, I'm gonna put my Altec 755Es on open baffles, and see how a complete open baffle system sounds in my room...
Peace
Re: W Baffle Dipole Sube w/PPA15s
I don't think the baskets are THAT flimsy. Sure, they're not cast aluminum, but I've definantly seen (and had) worse. I'm still not too sure as to why some of them come with spade terminals and others like mine come with binding posts. 😕
I believe I speak for everyone here when I say that I would like to see some pictures of your dipole subs, both complete and in the progress of building them.
I am glad to see that someone else has finally decided on buying some of these 15s and trying them out in an open baffle design. At least now, people will have the advantage of hearing the opinions of someone else with the same drivers, and in a different type of open baffle!! 😀
Roscoe Primrose said:
I don't think the baskets are THAT flimsy. Sure, they're not cast aluminum, but I've definantly seen (and had) worse. I'm still not too sure as to why some of them come with spade terminals and others like mine come with binding posts. 😕
I believe I speak for everyone here when I say that I would like to see some pictures of your dipole subs, both complete and in the progress of building them.
I am glad to see that someone else has finally decided on buying some of these 15s and trying them out in an open baffle design. At least now, people will have the advantage of hearing the opinions of someone else with the same drivers, and in a different type of open baffle!! 😀
Well I tried that RTA software and couldn't get anything to show up. It worked twice, then after that, everything kept coming up blank. No numbers, no graphs, nothing. The heck with it. I know it sounds good and that's all that matters to me.
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