internal sub cabinet design

[Fr3ak]

Hey all, just built my first sub cabinet:

8 cubic feet (20 x 20x 35) a1 birch
2x Dayton 15 inch drivers (4 ohm, 300 rms-700 peak)
2x 4 inch flared ports tuned to 45 Hz

is there any internal modifications i can make to the cab to get better spl / sound quality?


also, I'm thinking of returning the Dayton drivers and going with a pair of JBL 2226g (4 ohm) any thoughts?

Thanks for any help!

 

[WmAx]

Hey all, just built my first sub cabinet:

8 cubic feet (20 x 20x 35) a1 birch
2x Dayton 15 inch drivers (4 ohm, 300 rms-700 peak)
2x 4 inch flared ports tuned to 45 Hz

is there any internal modifications i can make to the cab to get better spl / sound quality?


also, I'm thinking of returning the Dayton drivers and going with a pair of JBL 2226g (4 ohm) any thoughts?

Thanks for any help!

For one thing, the ports are next to useless. You need to have a far higher cross sectional area to prevent port compression. Normally, folded slot ports must be used in order to get sufficient length practically (to in turn get the correct cross sectional area).

Which Dayton subs are you using? If you are using the 15" RS (Reference) series, these are a fine quality 'conventional' subwoofer. If you want much better performance, you need to go to significantly superior drivers and have a lot of power available. Even 12" drivers will outperform the 15" conventional subs, say, if you used high performance 12" such as JL Audio 12w7 and used a properly designed cabinet and port system. Also, you need to build seperate cabinet for each driver for optimal SQ. You get superior SQ by using a sub on each side of the room as opposed to a single point, unless you are crossing extremely low (say 50-55Hz with 4th order xover rate).

If you are serious about wanting killer subs, you need to build proper ports and use high performance drivers. The ultimate 15" would be TC Sounds AXIS or TC Sounds LMS drivers. But these cost considerably more than Dayton drivers, of course.

-Chris

 

[Fr3ak]

ok, im looking into returning the Dayton quartos and getting the rs's. How many cubic feet should i take out of the box?

 

[lsiberian]

Hey all, just built my first sub cabinet:

8 cubic feet (20 x 20x 35) a1 birch
2x Dayton 15 inch drivers (4 ohm, 300 rms-700 peak)
2x 4 inch flared ports tuned to 45 Hz

is there any internal modifications i can make to the cab to get better spl / sound quality?


also, I'm thinking of returning the Dayton drivers and going with a pair of JBL 2226g (4 ohm) any thoughts?

Thanks for any help!

Your approach is a bit unconventional, but I think you can get there. however i suggest you look at JL Audio or TC Sounds drivers. Exodus Audio is also acceptable.

You can model drivers using winISD. I suggest you ensure a port air velocity below 20 m/s at the most. It should be noted the cabinet size variance(within reason) doesn't effect performance as much as the port does. However if your cabinet is too large for the driver you may be more likely to blow it.

 

[highfigh]

Hey all, just built my first sub cabinet:

8 cubic feet (20 x 20x 35) a1 birch
2x Dayton 15 inch drivers (4 ohm, 300 rms-700 peak)
2x 4 inch flared ports tuned to 45 Hz

is there any internal modifications i can make to the cab to get better spl / sound quality?


also, I'm thinking of returning the Dayton drivers and going with a pair of JBL 2226g (4 ohm) any thoughts?

Thanks for any help!

How are you using this sub- music at high volumes or home theater, mainly for special effects? What are you using fro amplification, what main speakers are you using and what is the power output of the main amplifier? If you only need a narrow frequency band, you need to make the box and speaker so a resonant peak occurs in that range and falls off rapidly around it, and the system needs to have a high Q factor for this. A sensitive speaker driver is needed if you really want to reach high SPL and don't want to break the bank. Also, if your main speakers aren't very sensitive and your main amp isn't capable of high power, having monstrous bass from your sub just won't sound good. Blending the sub to the rest of the system seems to be ignored here but we don't know what you have for the rest of the system so it's impossible to say.

A box of that size needs a lot of bracing- what have you done about this?

 

[Fr3ak]

System= JBL JRX118sp crossed at 100hz feeding two behringer B212A's as mid and hf. for this project sub im using a BBE MaxX3 Xover feeding a QSC GX5 pushing two channels @ 700/4ohms to a bi-amp terminal with the jumpers removed on the back of the project sub (each driver gets a channel). I realize this new sub might be overkill for the behringers and JRX, but it will be use in a broad variety of systems. what im looking for is SPL at relatively low distortion that can be driven 6 hours at high power.


as far as the drivers,

I want to use it in live pa applications (parties)...has to be tough for when i haul it to locations and blast it all night.

I'm pushing this sub with a QSC GX5 (500/8ohms 700/4ohms) and i plan to use 4 ohm speakers so the amp can provide higher power to them as opposed to 8 ohms...

I was raised on JBL. all my buddies use JBL for live application and they seem pretty tough (we host music events in the mountains...lots of nasty abuse) But JBLs are pricey (666.00) for the two i was looking at. my price range is 400 for the pair.

as far as modding the box goes,

I was thinking of simply taking a skill saw at 45 degrees and trimming 4 or 5 inches off the depth all the way around and reattaching the rear panel to the newly angled cuts. this would drop the displacement to about 6 cubic feet from 8.

should i think about wave guides?...sorry for all the newb questions, I just realy want this project to turn out well. once again thanks so much.

 

[highfigh]

System= JBL JRX118sp crossed at 100hz feeding two behringer B212A's as mid and hf. for this project sub im using a BBE MaxX3 Xover feeding a QSC GX5 pushing two channels @ 700/4ohms to a bi-amp terminal with the jumpers removed on the back of the project sub (each driver gets a channel). I realize this new sub might be overkill for the behringers and JRX, but it will be use in a broad variety of systems. what im looking for is SPL at relatively low distortion that can be driven 6 hours at high power.

as far as the drivers, I want to use it in live pa applications (parties)...has to be tough for when i haul it to locations and blast it all night.

I'm pushing this sub with a QSC GX5 (500/8ohms 700/4ohms) and i plan to use 4 ohm speakers so the amp can provide higher power to them as opposed to 8 ohms...

I was raised on JBL. all my buddies use JBL for live application and they seem pretty tough (we host music events in the mountains...lots of nasty abuse) But JBLs are pricey (666.00) for the two i was looking at. my price range is 400 for the pair.

as far as modding the box goes, I was thinking of simply taking a skill saw at 45 degrees and trimming 4 or 5 inches off the depth all the way around and reattaching the rear panel to the newly angled cuts. this would drop the displacement to about 6 cubic feet from 8.

should i think about wave guides?...sorry for all the newb questions, I just realy want this project to turn out well. once again thanks so much.

Why cut at 45 degrees? I would cut it straight across with the blade at 90 degrees, install a cleat inside of the box and screw the back on. I would also consider mounting the woofers inside, but that's because I prefer not having them on the outside when I mount a grill0 I think they stick out too far. Many PA cabinets are made this way and it would be easier to make the modification.

How large is a typical space fro this use? If they're going to be used outside, I would use some kind of horn loaded design to improve directionality. There's no need for wide dispersion outside- you want the sound to go to a specific area.

 

[lsiberian]

Infinity makes some great drivers too. But you should definitely look at slot port designs with the drivers from soundsplinter or audiopulse. They are rebadged TC Sounds drivers. TC sounds makes the best drivers in the world. They will smoke the JBL's in sound quality and can take plenty of heat.

You can easily get 120 db per driver.

 

[Fr3ak]

i need five posts to post links... bare with

 

[Fr3ak]

one more...

 

[Fr3ak]

here are some pics

http://s97.photobucket.com/albums/l226/mdlsfreak/?action=view&current=IMG_0385.jpg

http://s97.photobucket.com/albums/l226/mdlsfreak/?action=view&current=IMG_0388.jpg

http://s97.photobucket.com/albums/l226/mdlsfreak/?action=view&current=IMG_0390.jpg


I cut all the edges minus the front at 45 degrees for a nice tight fit
reinforced the front baffle, recessed handles, steel corner protectors, bi amp bare wire/banana terminal

 

[highfigh]

What is the part number for those woofers? We can model them and see what it will take to get them to do what you want.

 

[WmAx]

OP: for your specific purpose, you need to forget normal home application designs. You need to build a professional type bass cabinet. The best/most efficient is a horn sub. Refer to measurements of a DIY horn sub using a 12" XLS Peerless driver:

http://www.hometheatershack.com/forums/subwoofer-tests-archived/980-diy-pa-horn-xls-12-a.html

In open field, extreme high output is achieved down to 40Hz(perfectly fine for music). If you are using it in a house, place in corners, and you will get very strong output down to 35Hz or so. Your amp power is far more efficiently used in case of a horn sub; though cabinet size is bigger than even ported. But it is not heavy; just use a high quality 13 layer hardwood cabinet plywood. Two of these things in a house, even a large room in a house, will produce more LF output than you can use (over 130dB will be easily achieved in a house), which as you know for parties/performance, 'more bass than you can ever use' is really 'just enough'.... .

-Chris

 

[Fr3ak]

driver= Dayton QT385-4 15" Quatro (part #295-560 on parts express)

specs:

Power Handling: 300 watts RMS/600 watts max
VCdia: 2-1/2"
Le: 2.4 mH
Impedance: 4 ohms
Re: 3.5 ohms
Frequency range: 20-125 Hz
Magnet weight: 67 oz.
Fs: 23 Hz
SPL: 91.8 dB 2.83V/1m, 88.8 dB 1W/1m
Vas: 5.89 cu. ft.
Qms: 12.57
Qes: .43
Qts: .42
Xmax: 9.84 mm

Also, quick side note. I'm a full time college student which means money's really tight. im looking to find a balance between economy and quality

 

[Fr3ak]

OP: for your specific purpose, you need to forget normal home application designs. You need to build a professional type bass cabinet. The best/most efficient is a horn sub. Refer to measurements of a DIY horn sub using a 12" XLS Peerless driver:

http://www.hometheatershack.com/forums/subwoofer-tests-archived/980-diy-pa-horn-xls-12-a.html

In open field, extreme high output is achieved down to 40Hz(perfectly fine for music). If you are using it in a house, place in corners, and you will get very strong output down to 35Hz or so. Your amp power is far more efficiently used in case of a horn sub; though cabinet size is bigger than even ported. But it is not heavy; just use a high quality 13 layer hardwood cabinet plywood. Two of these things in a house, even a large room in a house, will produce more LF output than you can use (over 130dB will be easily achieved in a house), which as you know for parties/performance, 'more bass than you can ever use' is really 'just enough'.... .

-Chris

I've heard folded subs have more latency as far as from when the signal hits the driver and when the sound leaves the cabinet...is this just something to over look?

 

[WmAx]

I've heard folded subs have more latency as far as from when the signal hits the driver and when the sound leaves the cabinet...is this just something to over look?

Well, you have the physical distance difference of course, in so far as the throat length, and effect on delay/latency, in a sealed back horn sub. Simply place the sub a couple of feet in front of the mid/high cabinets, or use an active crossover with the appropriate delay settings(you should be using an active crossover anyways, if you are serious about getting the best results).

-Chris

 

[WmAx]

http://www.prosoundweb.com/article/lsp_documentation_page_drawings_photos_specs_and_more/

The above link is to the plans for the LAB 12 project. It is a high performance DIY pro audio horn sub. Two of these units will be perfect. The driver is economical, and in this cabinet, it will product staggering performance for your purposes.

-Chris

 

[highfigh]

Well, you have the physical distance difference of course, in so far as the throat length, and effect on delay/latency, in a sealed back horn sub. Simply place the sub a couple of feet in front of the mid/high cabinets, or use an active crossover with the appropriate delay settings(you should be using an active crossover anyways, if you are serious about getting the best results).

-Chris

How long do you think a passive crossover would last?

 

[highfigh]

I agree- the acoustical energy (SPL) lost from using a passive crossover would be more than compensated for by using an active crossover and for those interested in bi-or tri-amping, this is a perfect example of an application where it's most appropriate. In a home, it's really not needed. The SPL needed in a large party, club or outdoors is much higher than what's needed in a home.

Go to a large club or a live gig and look at the speakers- they aren't necessarily large but they are efficient. Smaller, horn-loaded subs and multiple mid-high frequency cabinets, often in a line-array. Easier to move, too.

 

[Fr3ak]

http://www.prosoundweb.com/article/lsp_documentation_page_drawings_photos_specs_and_more/

The above link is to the plans for the LAB 12 project. It is a high performance DIY pro audio horn sub. Two of these units will be perfect. The driver is economical, and in this cabinet, it will product staggering performance for your purposes.

-Chris

wow, that looks pretty badass. But there's no way way I would be able to do this with my experience and lack of precision tools. I think ill try to improve my recent project sub for now. Someday though, I definitely want to tackle this project! Thanks for the link.