help building my box! my brain is exploding!

[torval]

so i ordered a "Peerless 835017"
Peerless 835017 12" Aluminum Cone XXLS Subwoofer


i heard a lot about this sub, but trying to enter the t/s parameters and getting them to work has been a pain (there is 1 version of the t/s parameters listed on the parts express page and another listed on the pdf gotten from that same page).. i've read a 3.6 cubic foot box tuned to 22 hz would be perfect for this sub. yet when i model it in winisd it is 6db down at 20hz with both profiles of the peerless sub i created using the given t/s parameters. is the room gain in a 12x10 room going to make up for the steep drop off aftter 40hz i see in my calculations?

i modeled a 7 cubic foot box tuned to 21hz and got + or - 1 db from 20 to 200 hz. if that is wrong tell me. i want a musical sub that will play down to a REAL 20hz.

i am using a dayton 250w rms plate amp btw.
Dayton Audio SPA250 250 Watt Subwoofer Plate Amplifier

so tell me, am i right about the large 7 cubic foot box? i have room and i want this to be the last sub i build for 10 years or so. i'm very new to all this and probably should have just ordered an svs pb2000 but i wanted something custom that i built, and to save a bit of money over the svs.

 

[torval]

well someone erased everything i wrote. basically i bought a peerless 12 inch 835017 Peerless 835017 12" Aluminum Cone XXLS Subwoofer

i want to build a nice box for it that will play down to 20hz. i used winisd to model a box recommended to me at 3.6 cubic feet and 22 hz tuned port but i got fall off starting at 40hz and 6 db down at 20hz.

i modeled a 7 cubic foot box tuned to 20hz and got pretty darn flat response within 1 db from 20 to 200hz.

my question is will the 3.6 cu foot boxes roll off from 40 to 20 hz be made up for by room gain? is my 7 cubic foot box going to be a realistically good sounding sub considering i do have room to build that big of a box?

my friend is a great woodworker and he will help me i just need to know some ideas of what to build. i want something that will play + to - 3db down to 20hz. that is my only requirement.

 

[wintermute]

Hi torval, your first post disappeared because if you edit a post whilst under moderation it goes back onto the queue for approval. There haven't been any mods around this morning so it sat for quite a while in the queue. It's back now.

Tony.

 

[GM]

Yes, this is a problematic driver and why it's normally in a small cab tuned low using a PR since it needs a large, long vent to handle high power.

Its Qts is close enough to spec a Vb = Vas, so 7 ft is a little large unless a high enough aspect ratio cab is used [MLTL], but ~6.1 ft^3 is large enough, though in both cases using a 60" high cab still ideally requires a much too long vent.

That said, assuming a typical room, like a bedroom, it's room gain will begin around ~565/12 = ~47 Hz, so figure 3-4 dB/octave gain below this point unless it's a really massive construction to increase it to near its 6 dB/octave limit.

This would theoretically allow a leaky sealed cab to work, i.e. start sealed, then if it rolls off too much drill A 1/4" hole in it where a vent would go and tape a coffee filer or other piece of damping over it and keep doing this until you're getting the desired roll-off. Worst case you wind up using Peerless's PR.

GM

 

[Inductor]

so i ordered a "Peerless 835017"
Peerless 835017 12" Aluminum Cone XXLS Subwoofer


i heard a lot about this sub, but trying to enter the t/s parameters and getting them to work has been a pain (there is 1 version of the t/s parameters listed on the parts express page and another listed on the pdf gotten from that same page)..

The preliminary reference (pdf) is usually wrong/outdated. In the one on Parts Express website, you can read the date of 24/Jan/2009.
The other data should be fine, belonging to 12/Apr/2010 of same driver with reference #XXLS-P835017.
You can also find a different data/reference of same driver here in Germany but any of them should be fine. Just be careful when using/looking at preliminary T/S parameters for simulation that go trough different phases of manufacturing.

 

[GM]

FWIW, I simmed them and they overlaid almost perfectly, certainly an audibly imperceptible difference.

GM

 

[Inductor]

i want a musical sub...

Use a KEELE & HOGE alignment with PEERLESS XXLS-P835017, VB = 153.9 L, FB = 20.3 Hz.
You will need the extra space for ports, reinforcements and driver.
AES Papers -- Official website of D.B.Keele
For room gain consider +3dB@LF.
For a ruler flat driver to 20Hz +/-1dB consider instead the 15" DAYTON TS400D-4 TITANIC MK 4, that I know is out of question, just for your thoughts.

 

[torval]

i'm open to using a 15 i can always return the peerless. i'd like good suggestions for what box to use for the peerless also though.

 

[hollowboy]

my question is will the 3.6 cu foot boxes roll off from 40 to 20 hz be made up for by room gain?

The data-bass web site has a great page on room gain. The pic below is from there. Your room is smaller than their test room, so I'd imagine your gain would start at a higher frequency.

Note that their measured gain was very uneven, even when multiple sub locations and measuring positions were used
... so you may have a 10dB boost or a 10dB notch at 20Hz, depending on where you sit, how your room is arranged and so on. Meaning some experimentation may be needed for you to get ~6dB gain at 20Hz.

In some of my own tests, I have measured big bass notches that vanish (for the same mic and speaker position) when I simply open a side door. You might find that changing the sub's position, adding or shifting bookshelves etc makes a similarly big difference for you.

An externally hosted image should be here but it was not working when we last tested it.

is my 7 cubic foot box going to be a realistically good sounding sub considering i do have room to build that big of a box?

Bigger is better, usually. Just be 100% sure you can lift it, and get it through doors

 

[bjorno]

Peerless 835017

Hi All,

FYI: IMO: The Peerless 835017 is a great Driver..

b

 

[Inductor]

Yes very, very nice driver.
And funny thread title from OP...
Have fun.

 

[torval]

bjorno i don't understand that picture with all those charts one bit. i'm looking basically for flat as i can response from 20-100hz, i'm open to using other drivers as well but i'm gonna at least try a few boxes while i have this thing.

btw, will a bigger box sound less "tight". i've never built my own sub before.

oh and winisd recommends a 4 inch port 9.68 inches long to tune a 6.1cu foot box to 21hz. does that sound right?

 

[jf4828]

So what is your application? There are trade offs in any box recommendation so it's helpful to know... Primarily HT or music? If you want something to sound super "tight" you may have to trade 20hz extension or max SPL.... What are your thoughts on this? Also, how capable are the mains and what frequency will you cross to them?


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[torval]

well i now know what i DON'T want. i auditioned an svs pb-2000 in my room and it just has too much 'roar' and lows that sound "whooshy", additionally it seemed to be exact, and play well, it just added too much roar to where i didn't feel there should be. any. i noticed that my old sony SAWM-500 used to do this too, it was ported also.
that being said, it is still the best sounding subwoofer i have ever heard.. it is still quite fast and musical and i heard notes i'd never heard before or in a way i never had.

now im thinking sealed. as i said i'll probably try a few boxes.

btw this sub is almost strictly for nusic, but i do want awesome dubstep bass and hard hitting double bass.drum.

oh and my mains are athena point fives.

http://www.amazon.com/Athena-15345-Theater-Discontinued-Manufacturer/product-reviews/B0002H6M0S

i did not get the subwoofer just the 5 speaker set. they play relatively low. much better than i expected. it is by no means an audiophile system but they sound pretty good. i just couldn't justify shipping a 120 dollar subwoofer 1300 miles when i moved. soooo here i am.

 

[jwrisk]

Hi Torval,

As far as I can see, I think you might have different measuring units between the program and the speakers parameters, just one of them you get wrong and you'll end up building a refrigerator for a speaker box. Try winspeakerz https://www.trueaudio.com/win_abt1.htm
I have been using it for over 13 years and never screwed up a box.

Regards,

John

 

[Inductor]

Obvious, another nice project for pros (op) John. Difficult to calibrate to taste, what might take a couple of years of fun with all the basics already set, meaning the xover components and sizes of enclosures.

 

[jf4828]

3.5 - 4 cubic feet tuned to 22hz gets you an f3 in the low 20s. You will hit xmax at 30hz@175 watts and about 108db. This is maximally flat configuration.... For music, I'd go sealed 1-1.5 cubic feet. This puts your f3 in the 40s but you have room gain. This is perfect for music if you ask me. However the trade off here is you lose bottom octave. You can always use a minidsp or plate amp with a 6db bump on the bottom but you will hi excursion limits at around 100dB at 30hz sealed. Note though that you can still hit 108db in at 175 watts above 50hz... Obviously group delay for the sealed configuration is much better! Personally, I have a 12 inch HSU for home theater plus a stereo pair of peerless 10" subs sealed and crossed to bookshelf fronts! A pretty great sounding setup in my opinion. Since I'm a music guy, I'd rather have 1 od my peerless sealed subs over 1 ported HSU sub... Not to say ported can't sound great, but it's harder to get right the first time....


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[jf4828]

See attached graphs for model showing response, excursion and group delay at 175 watts for sealed 42 liter and ported 100 liter tuned to 22 hz.