So I decided on the Peerless 831858 that is on sale at madisound. Using Winisd, I have decided to put it in a 32L box tune to 28Hz using two 1 in diameter 4in length ports.
The curve looks pretty flat and the extension and group seems good for music as far as I can tell with my limited knowledge. So how is this setup? Does it look alright? Any comment is appreciated. Thanks!
PS. This is a sub that will be eventually use with a pair of super elf or elf 1.5 as my computer sound system.
The curve looks pretty flat and the extension and group seems good for music as far as I can tell with my limited knowledge. So how is this setup? Does it look alright? Any comment is appreciated. Thanks!
PS. This is a sub that will be eventually use with a pair of super elf or elf 1.5 as my computer sound system.
Hi,
I don't have specs of this particular driver to model it in my copy of Lspcad, however 1" diameter ports seems a little on the small side to eliminate air speed noises. May be better to use 2" or 3" ports and make them longer to get required tuning.
Cheers
I don't have specs of this particular driver to model it in my copy of Lspcad, however 1" diameter ports seems a little on the small side to eliminate air speed noises. May be better to use 2" or 3" ports and make them longer to get required tuning.
Cheers
I calculated the port diameter and length via isd online and this give a vent mach less than 0.16 which should not give me any port noise.
never used the winisd online version--i suggest u download the alpha pro and use that.. possibly the online version is estimating at 1w of power---did you enter in the max power you will be deliving to the sub as a parameter as well??
-chris
-chris
Driver specs?
BTW, WINISD has errors in it, so be forewarned! Also, <5% mach vent speed (0.05) is where you need to be for best performance as long as the pipe doesn't get too long for the sub's intended BW. 16% will be audible unless some means is used to damp it, though I've had folks tell me that subs with a 20% calculated vent mach sound fine to them, so YMMV.
GM
BTW, WINISD has errors in it, so be forewarned! Also, <5% mach vent speed (0.05) is where you need to be for best performance as long as the pipe doesn't get too long for the sub's intended BW. 16% will be audible unless some means is used to damp it, though I've had folks tell me that subs with a 20% calculated vent mach sound fine to them, so YMMV.
GM
yes i must compare sub sim,dosbox,winisd old,new and any other i can find...see what teh diff is
my winisd 33hz box turned out just how winisd said-=also a mate with a good spreadsheet double checked it
my winisd 33hz box turned out just how winisd said-=also a mate with a good spreadsheet double checked it
Unixbox tells me I will have problems with that port size 🙁 Guess its back to the drawing board. Thanks for pointing that out.
OK
Found some specs on this driver. Lspcad shows for this box size & tuning minimum 2 ports 50mm dia (2") by 310mm long (12") - better would be 2 50mm ports 280mm long in a 49.8 litre box - tuning point would be 22.7Hz.
Cheers
Found some specs on this driver. Lspcad shows for this box size & tuning minimum 2 ports 50mm dia (2") by 310mm long (12") - better would be 2 50mm ports 280mm long in a 49.8 litre box - tuning point would be 22.7Hz.
Cheers
Ok, let me run some more simulations with those numbers. Can anyone explain to me why Madisound recommends a 15L box tuned to 45Hz? I ran the simulation on that and the frequency response curve doesn't look so good. It has a bump in the frequency.
Oh I forgot to say that this is the Peerless driver that is on sale at Madisound. specs:
High-end 8" subwoofer. Peerless CC line. Double voice coil. Rubber surround, thick poly cone, extra-heavy magnet system. Great in small bass reflex or band-pass sub.
8 + 8 ohms; Fs 22 Hz; Qts .23, Vas 79.8, 90.5 db, 200 watts
x-max 7 mm
15 liters ported
Port size 1.5" x 5.4" or 2" x 10"
F3=45 Hz
Oh I forgot to say that this is the Peerless driver that is on sale at Madisound. specs:
High-end 8" subwoofer. Peerless CC line. Double voice coil. Rubber surround, thick poly cone, extra-heavy magnet system. Great in small bass reflex or band-pass sub.
8 + 8 ohms; Fs 22 Hz; Qts .23, Vas 79.8, 90.5 db, 200 watts
x-max 7 mm
15 liters ported
Port size 1.5" x 5.4" or 2" x 10"
F3=45 Hz
For box size 49.8L and tuning point of 22.7hz, the sub shows extremely high group delay. This is a bad thing correct?
I assume Madisound either has more accurate specs to work from or is catering to the car boombox crowd. BTW, efficiency is closer to 87dB/W.
Group delay increases with decreasing frequency. Fortunately, if tuned low enough and there's no 'ringing' peak at Fb, it will decay away enough not to be obviously audible due to our poor LF hearing acuity. It can be lowered to near sealed values by 'critically' damping the vent, with reduced vent output being the tradeoff. With this driver though, it will roll it off enough that you might as well stick it in a sealed cab.
FWIW, based solely on the specs presented and its intended app, 20L/27Hz with a 6.35cm diameter vent seems to me to be the best tradeoff between BW, group delay (transient response), low distortion/vent mach, and power handling.
GM
Group delay increases with decreasing frequency. Fortunately, if tuned low enough and there's no 'ringing' peak at Fb, it will decay away enough not to be obviously audible due to our poor LF hearing acuity. It can be lowered to near sealed values by 'critically' damping the vent, with reduced vent output being the tradeoff. With this driver though, it will roll it off enough that you might as well stick it in a sealed cab.
FWIW, based solely on the specs presented and its intended app, 20L/27Hz with a 6.35cm diameter vent seems to me to be the best tradeoff between BW, group delay (transient response), low distortion/vent mach, and power handling.
GM
GM,
The response seems pretty good. The decay in frequency response starts off pretty early but it is going at a slow rate. I will be placing it in a small/medium type room so room gain should boost the 50-30Hz spectrum by a bit correct? This will give me a pretty decent extension.
The response seems pretty good. The decay in frequency response starts off pretty early but it is going at a slow rate. I will be placing it in a small/medium type room so room gain should boost the 50-30Hz spectrum by a bit correct? This will give me a pretty decent extension.
Should. Since it's for a computer I figured it would be close and probably on the floor against the wall so there should be enough LF to EQ it flat and still be plenty loud.
GM
GM
I just noticed that with the 20L/27Hz design, unibox indicates that the woofer will go past peak cone excursion in the 40-50Hz range. Will this be a problem?
Well, it's potentially going a little over Xmax if fed a 200W peak, but not nearly enough to cause damage or be audible. Also, assuming it's near the floor there will be a ~ +3dB boundary gain so that more than compensates it. Really, unless you sit it out in the middle of the room there should be enough boundary/room gain to allow you to attenuate some of this BW to flatten out its response down to below Fb.
GM
GM
seeing as how I am also talking about a computer sub using 8inch driver(s)... and the "having the last word" thread was closed... 
I thought I would ask here.. lol
what do ya think of these?
http://www.advanceae.com.au/car/prod4.htm
I was thinking of putting 2 in a 60litre box tuned to 35Hz... looks something like this... lol anyway.. I have no money... but I was wondering what you guys thought of these "subs" maybe I should just finish my towers first... 🙄
I thought I would ask here.. lolwhat do ya think of these?
http://www.advanceae.com.au/car/prod4.htm
I was thinking of putting 2 in a 60litre box tuned to 35Hz... looks something like this... lol anyway.. I have no money... but I was wondering what you guys thought of these "subs" maybe I should just finish my towers first... 🙄
An externally hosted image should be here but it was not working when we last tested it.
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I tried simulating with 2 of the the Peerless, which are cheaper, in a 70L/30Hz and it mimics yours frequency response except giving better extension as well as more SPL. But then I am still learning. Take my words with a grain of salt. =P
Is it just me or is that site way more expensive than others? Their Peerless XLS 10" is almost $300. You can probably find better than that venom driver, it only has 5mm of xmax but it looks like they tried to make it LOOK impressive with that big surround. Try ebay and see if there's anything decent on there with the right ts specs. I got my sub driver for $40 off on ebay and it has a return policy and full warranty and all that, there's some good deals to be had if you wait for them to pop up. To lower the Q you could try an aperiodic vent if you do a sealed box, and a bass boost could lower the f3.
Tell us how it sounds when it's all done.
Tell us how it sounds when it's all done.
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