Turbodawg,
"Impressive" is a useless metric for describing a sub.
"Accurate" is hearsay without frequency response (and some would argue, distortion) measurements.
"Practicality" is meaningless without some size limit.
My home theater uses a pair of Pioneer 12" woofers (under $50 used) in a 28" x 20" x 19" sealed enclosure made from a 2" thick particle board door found in an alley.
My girlfriend and I have often been "impressed" by LF sound effects in movies that the sub does, yet it is only capable of around 105 dB before distortion is objectionable.
The Tub Sub in post #8 can do 114 dB at 40 Hz using only 15 watts or so with distortion under 10%.
If 105 dB is "impressive", is 114 dB "supercalifragilisticexpialidocious"?
Seriously, put in a "X dB at X frequency, or this thread is useless- otherwise the next post could be a speaker mounted on an open baffle that is actually capable of only an "impressive" 75 dB at 40 Hz
Art
Fair enough. "People" find the bass produced by the Bose Acoustimass 5 system to be "impressive", the cost is compariable, and most normal people would agree that they are very practical for use in a normal living area:
An externally hosted image should be here but it was not working when we last tested it.
Bose Acoustimass 5 Home Speaker System - Surround Speaker System ? Home Theater Speaker Systems
http://products.bose.com/pdf/customer_service/owners/og_am5iii.pdf
intellexual net · m k i v
From what I can gather and calculate from the information available, the "sub" produces, roughly, at lowest extension and peak output, 109 db @ 1m 4pi @ 45hz. (when powered at the max rated input of 2 x 200w, given a 85 db/w/m/4pi sensitivity, -2db @ 45hz, not accounting for power compression, not sure if the drivers are being pushed to x-mech in that senario, but whatever)
So, figure a sustained sine wave output capablity of 106 db @ 1m 4pi @ 45hz.
Please note the unit's size is 14"H x 19"W x 7.5"D @ 18.8 lbs. That should not be taken as criteria, just a baseline as to what the public typically finds acceptable.
Feel free to make your own tradeoffs of performance vs. size, but you have to beat the bose overall. If you build a sub larger,
it should certainly have the performance to justify it - increase output 3db for each doubling of size or by a comparable improvement in extension.
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If "People" find the bass produced by the Bose Acoustimass 5 system to be "impressive", they have never heard a real subwoofer
.I have heard them, and under every parameter you have referenced other than size, they are an epic FAIL.
Also, I seriously doubt that the two 5.25" speakers could sustain a sustained sine wave output at 106 dB for more than a few seconds without smoke emitting from the 6th order boombox port.
Although the Tub Sub can go an octave lower, and (at least) 6 dB louder with a tiny fraction of the power, it is 10.93 times larger (12.57 cubic feet compared to the toy sub 1.15 cubic feet).
If you want to penalize 3 dB for doubling of size, it would need to do 138.79 dB, that ain't going to happen for $500.
Does your OP sub pass the +3 dB per doubling of size parameter ?
Art
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If "People" find the bass produced by the Bose Acoustimass 5 system to be "impressive", they have never heard a real subwoofer
I have heard them, and under every parameter you have referenced other than size, they are an epic FAIL.
Also, I seriously doubt that the two 5.25" speakers could sustain a sustained sine wave output at 106 dB for more than a few seconds without smoke emitting from the 6th order boombox port.
Well, you asked for criteria and I gave it to you. In summary:
- Sine wave output capablity of 106 db @ 1m 4pi @ 45hz
- Reference size of 14"H x 19"W x 7.5"D @ 18.8 lbs
- For each doubling of size, increase output 3db or improve low extension by 1/2 octave
Thus, if you were to double size twice to build a sub 75lb & 14"x19"x30", it should be capable of 109 db 1m 4pi @ 34 hz or 112 db 1m 4pi @ 45 hz or 106 db 1m 4pi @ 22 hz.
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What is the time frame that you give us for building the sub?
I am currently gathering parts for a motional feedback subwoofer build to shake things up a bit at home. I have found a nice driver from Seas with a dual voice coil, I am planning to drive one voice coil and use the other coil for the feedback signal.
The parts and costs for my sub so far are:
10" Seas driver with dual voice coil (secondhand); 50 euro
18mm MDF for enclosure: 22 euro
8mm MDF for frontpanel: 8 euro
Screws and glue: 10 euro
cloth for frontpanel: 7 euro
20cm speaker cable: 0.20 euro
Amplifier parts (passive and active parts): 88 euro
Big heatsink: free
The total money spend at the moment is 185.2 euro, or 247.28 dollar. I am still in doubt whether I want to spray paint the enclosure or use some nice wood veneer to match my speakers.
I am currently gathering parts for a motional feedback subwoofer build to shake things up a bit at home. I have found a nice driver from Seas with a dual voice coil, I am planning to drive one voice coil and use the other coil for the feedback signal.
The parts and costs for my sub so far are:
10" Seas driver with dual voice coil (secondhand); 50 euro
18mm MDF for enclosure: 22 euro
8mm MDF for frontpanel: 8 euro
Screws and glue: 10 euro
cloth for frontpanel: 7 euro
20cm speaker cable: 0.20 euro
Amplifier parts (passive and active parts): 88 euro
Big heatsink: free
The total money spend at the moment is 185.2 euro, or 247.28 dollar. I am still in doubt whether I want to spray paint the enclosure or use some nice wood veneer to match my speakers.
That's easy... the box size you state, ported to 40hz. Hits 109db in 4pi at 45hz @24v per driver
(2) mcm 55-2421 drivers - $30 each
(1) Yung 300w plate amp - $99
all done dirt cheap. Build a pair of them and enjoy.
Jbell's entry in post #25 appears to be the current winner by the new rules.
4pi is in my opinion, a poor way to rate subs, a perfect corner does not exist in reality.
Half space is the professional standard for rating subs.
You should repost the revised rules in your OP (you can edit OPs).
Sine waves contain 3 dB more power (3 dB crest factor) than an AES (6 dB crest factor compressed pink noise) rating, the Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm you use in your entry handles 800 AES, which would be 400 watts sine wave.
You may want to delete your offering, a 4.5 cubic foot speaker with 87 dB sensitivity powered by 400 watts sine wave reaches 113 dB, but is 3.9 time larger than the Bose, so needs to do 117.74 dB
.Art
Jbell's entry in post #25 appears to be the current winner by the new rules.
4pi is in my opinion, a poor way to rate subs, a perfect corner does not exist in reality.
Half space is the professional standard for rating subs.
You should repost the revised rules in your OP (you can edit OPs).
Sine waves contain 3 dB more power (3 dB crest factor) than an AES (6 dB crest factor compressed pink noise) rating, the Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm you use in your entry handles 800 AES, which would be 400 watts sine wave.
You may want to delete your offering, a 4.5 cubic foot speaker with 87 dB sensitivity powered by 400 watts sine wave reaches 113 dB, but is 3.9 time larger than the Bose, so needs to do 117.74 dB
Art
4pi space is full space, free air, anechoic.....
Criteria for doubling size twice or 4x is as I provided above:
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There are plenty of horn subs that only get down to there or so, plus I provided the criteria for increasing size vs. extension.
Sine waves contain 3 dB more power (3 dB crest factor) than an AES (6 dB crest factor compressed pink noise) rating, the Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm you use in your entry handles 800 AES, which would be 400 watts sine wave.
You may want to delete your offering, a 4.5 cubic foot speaker with 87 dB sensitivity powered by 400 watts sine wave reaches 113 dB, but is 3.9 time larger than the Bose, so needs to do 117.74 dB
Art
I think you'll find you're a bit off on the Dayton. Spec sheet calls for 800 wrms, not AES.
Dayton Audio RSS390HO-4 15" Reference HO Subwoofer 4 Ohm 295-469
yea I'm not sure what's up with the 4pi requirement... most interior subs are really loaded about 1pi. However the dual mcm ported cabinet satisfies the 'rules' and exceeds spl requirements by 3db... ON THE CHEAP.
Personally I'd go a bit more expensive and go passive radiator, not ported. Then you'll get some true deep HT rumbles out of it. No cheating involved.
Dayton 12" pr's are $20 each. Use a pair. Subs on the 'skinny' end, and a PR on each "side"
It's still only $200 per cabinet in parts. You could accomplish a pair under $500 and place them around the room to even out your modes.
Personally I'd go a bit more expensive and go passive radiator, not ported. Then you'll get some true deep HT rumbles out of it. No cheating involved.
Dayton 12" pr's are $20 each. Use a pair. Subs on the 'skinny' end, and a PR on each "side"
It's still only $200 per cabinet in parts. You could accomplish a pair under $500 and place them around the room to even out your modes.
I know this, and if you want to convert it, be my guest. I'm just using it because of the sensitivity measurement of the bose is anechoic, which was used to calculate the criteria.
So you want people to test their home subs suspended several hundred feet in the air or in an anechoic chamber good down to 45 Hz
?I get what you mean now for size:
1.15 cubic feet 106 dB at 45 Hz (Bose toy sub size, using inflated max SPL level)
2.3 cubic feet 109 dB at 45 Hz
4.6 cubic feet 112 dB at 45 Hz
9.2 cubic feet 115 dB at 45 Hz
18.4 cubic feet 118 dB at 45 Hz
So the Tub Sub at 12.57 cubic feet may still squeak in by that criteria, but no way am I renting a crane to prove it
.So you want people to test their home subs suspended several hundred feet in the air or in an anechoic chamber good down to 45 Hz
I get what you mean now for size:
1.15 cubic feet 106 dB at 45 Hz (Bose toy sub size, using inflated max SPL level)
2.3 cubic feet 109 dB at 45 Hz
4.6 cubic feet 112 dB at 45 Hz
9.2 cubic feet 115 dB at 45 Hz
18.4 cubic feet 118 dB at 45 Hz
So the Tub Sub at 12.57 cubic feet may still squeak in by that criteria, but no way am I renting a crane to prove it
Modeling in 4pi in hornresp will be sufficient here.
No offense intended...
And as far as real 4pi, and bose 4pi... well here's a clip from bose's own site.
Our anechoic chamber sits on springs, a room within a room, isolated from the rest of the Bose Research and Development facility. Inside, dense and meticulously arranged fiberglass wedges protrude from all angles. The 24" wedges absorb all sound above 100Hz,
I don't trust any 'chamber' results below 125hz, and in fact feel like bose 45hz measurements probably don't line up exactly with a modeling program like hornresp.
That said, +3db@45hz (minimum) from a pair of $30 drivers in the same size enclosure should flat out embarrass bose... and I think is sufficient for your 'challenge.'
To make it more compelling, you could build a quad of the subs, and add a PA amp, and still be under $500. That's 120db@45hz in 4pi space.
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I did not find any test protocol on the Dayton website, but find it hard to believe it would handle much more power than the larger voice coil Lab 15.
Like all the other Eminence product Parts Express misquotes the power rating of the Lab 15 as RMS, when Eminence clearly states the use of the EIA 426A noise source.
The EIA 426A noise source is used by most manufacturers, I'd think Dayton would use it too.
Go ahead and try putting an 800 watt sine wave in to your Dayton Audio RSS390HO-4 15" Reference HO Subwoofer and tell me what color smoke comes out
.Speaking of smoke, can you post the Bose anechoic chamber (above 100 Hz) frequency response of the toy sub?
Art
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I pulled the 85 db/w/m figure as an anechoic measurement of the sat's from a website that claimed that it was an indy test. So the figures presented are a high side educated guess, purely a nominal figure for the sake of comparison. It would be interesting to see what one of these actually does with a 400w 45hz sine wave............LOL.
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