Recommendations for a cerwin vega 12" box

[tonydahose]

i recently found my old sub which was in the corner behind my big projection TV had dry-rotted and sounded like crap. i tossed the speaker but the box looks pretty good and is solid. it has a passover and is ported. the dimensions are 16.25" X 10" X 25" the port is 7" long 2 & 3/4" inside diameter. it is probably close to 20 years old. IIRC it is a dual voice coil speaker. as far as ohms i am clueless. i am probably going to be buying a STF-1 sub for my main room, i am going to put this box in my garage. i am looking for a cheap but decent sub woofer for this box...any thoughts? thanks

 

[lsiberian]

The box is approx 1.7 cu ft with a 35hz tune.

It would be good for either sealing up or a nice music sub. You won't get the really low stuff like many other subs. But I can take a crack at a few 12" options and see if something models alright in it.

I suggest you seal up the port. For simplicity's sake

for this you'll need to cut a circle that fits perfectly. Seal it up

Sealing a port is tricky business but I've done it before. So If you want any pointers feel free to ask.

I know a lot of the folks here will find this whole idea crazy, but I'd be willing to give it a go design wise.

I'll need more details on the box to further help you. Like the thickness of the material used.

For fun I modeled the Simple 12.1 Infinity Perfect subwoofer driver in a sealed 1.7 cuft box and it actually does pretty well considering the limitations of the design. And with some EQ applied you can do pretty well for a little home theater setup.

What's your budget?

 

[tonydahose]

3/4" mdf with a laminate on the outside. as far as filling the hole, i can handle it, I dabble in woodworking. my budget is cheap..lol i just spent $275 on the STF-1, plus a 58" plasma and the TV stand..i was thinking of a rebuilt infinity on ebay or something like that. i just didnt know about the port. thanks for the reply.

 

[lsiberian]

3/4" mdf with a laminate on the outside. as far as filling the hole, i can handle it, I dabble in woodworking. my budget is cheap..lol i just spent $275 on the STF-1, plus a 58" plasma and the TV stand..i was thinking of a rebuilt infinity on ebay or something like that. i just didnt know about the port. thanks for the reply.

too bad you don't have the 275 it would open a lot of options.

Most cheap drivers are that way for a reason.

http://www.diycable.com/main/product_info.php?cPath=24_93&products_id=653 would be an excellent driver and is capable of 115db in it's major range

You'd need an EQ if you want to use it for home theater.

You'll need to seal the port as always, but you could get some nice output with it.

 

[highfigh]

3/4" mdf with a laminate on the outside. as far as filling the hole, i can handle it, I dabble in woodworking. my budget is cheap..lol i just spent $275 on the STF-1, plus a 58" plasma and the TV stand..i was thinking of a rebuilt infinity on ebay or something like that. i just didnt know about the port. thanks for the reply.

What is the port made of? If it's a cardboard or plastic tube, you should be able to remove it. If you have a router, you could use a rabbet bit with a smaller bearing to create a shoulder and with a circle cutting jig, make a disc that will fit flush. If you find a driver that needs a slightly smaller enclosure and you won't be using the port at all, you can remove internal volume by attaching MDF to the inside.

 

[lsiberian]

What is the port made of? If it's a cardboard or plastic tube, you should be able to remove it. If you have a router, you could use a rabbet bit with a smaller bearing to create a shoulder and with a circle cutting jig, make a disc that will fit flush. If you find a driver that needs a slightly smaller enclosure and you won't be using the port at all, you can remove internal volume by attaching MDF to the inside.

If it's plastic I usually can pop it out pretty easy, but be careful I've had some launch off on me.

 

[tonydahose]

thanks for the hints with the router jig, i have made 2 of them, one for big circles and one for small. this box has some nice stury legs and the bottom is shallower than the sides so i was just going to use some gorilla glue and a scrap a few inches arger than the hole and srew it in. the speaker was too much for me right now and this is going in the garage so it doesnt need to be high end. i plan on building the infinity kappa plan that is in the forum when i do my addition. with the plans it should be simple to build..the eq part i will ask about when the time comes. now back to this one. i called cerwin vega to ask what type of impendance the old sub was and they couldn't tell me. it isn't anywhere on the speaker itself. i grabbed it out of the garbage and checked. since this is a passive passover and it puts the rest of the signal out the left and right channel speakers does it matter if the sub is 2, 4, or 8 ohms? will it mess up the receiver or the speakers if it isn't the correct one ?

i know these are cheap POS but for where it is located it will be more than good enough.

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=Emerson+Mobile+12

which one should i get?

 

[highfigh]

thanks for the hints with the router jig, i have made 2 of them, one for big circles and one for small. this box has some nice stury legs and the bottom is shallower than the sides so i was just going to use some gorilla glue and a scrap a few inches arger than the hole and srew it in. the speaker was too much for me right now and this is going in the garage so it doesnt need to be high end. i plan on building the infinity kappa plan that is in the forum when i do my addition. with the plans it should be simple to build..the eq part i will ask about when the time comes. now back to this one. i called cerwin vega to ask what type of impendance the old sub was and they couldn't tell me. it isn't anywhere on the speaker itself. i grabbed it out of the garbage and checked. since this is a passive passover and it puts the rest of the signal out the left and right channel speakers does it matter if the sub is 2, 4, or 8 ohms? will it mess up the receiver or the speakers if it isn't the correct one ?

i know these are cheap POS but for where it is located it will be more than good enough.

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=Emerson+Mobile+12

which one should i get?

I doubt it's 2 Ohms. If you have access to a multi-meter, set it to Ohms and measure from one terminal to the other. If it's about 3.2 Ohms, it's a 4 Ohm speaker and if it's about 6.4 Ohms, it's an 8 Ohm speaker.

It has a red surround, right? If not, either it was repaired or the dust cap from a C-V was used on a different speaker. Look on the frame for a 6 digit number. That will be hte date code and hte first three digits are the manufacturer code.

Here's a link for some common ones. If it has one of these, they have them made for them, to their spec. Eminence still makes a lot of speakers for other manufacturers and it could easily be one of theirs.

http://www.triodeel.com/eiacode.htm#speakers
and
http://www.unclespot.com/speakerEIAcodes.html

If the crossover is passive (inside the sub and handles routing the bass to the woofer and the highs to the main speakers), the impedance does matter. If you can get to the crossover, look at the capacitor for the highs- of it's about 330uF, it's for 4 Ohm speakers and if the woofer has a coil and cap, post the values here (you may not see anything on the coil).

If the impedance is 4 Ohms and the crossover is designed for 8 Ohms, the crossover point will shift up 100% (double the frequency) and if it was designed for 4 Ohms and you connect it to an 8 Ohm speaker, it will go down to half of what it's supposed to be.

 

[tonydahose]

thanks for all your help with this. when i called CV the tech said it wasn't listed in his computer. i had emailed the tech support the previous nite. i got a response from someone who could look up the right info:

SW-12B Specifications



WOOFER: 12” Dual Voice-Coil (RW-12D or 122D2)

POWER HANDLING: 125 Watts/Coil

FREQUENCY RESPONSE: 29-100Hz

SENSITIVITY: 92 dB

IMPEDANCE: 8 Ohms/Coil

CROSSOVER FREQ: 100Hz with High-Pass Outputs

WEIGHT: 48 lbs.

DIMENSIONS: 13¼” X 25½” X 16¼”

MSRP: $320

CIRCA: 1990


so i NEED to find an 8 ohm 12 dual voice coil sub to make this work properly, correct?

 

[lsiberian]

thanks for all your help with this. when i called CV the tech said it wasn't listed in his computer. i had emailed the tech support the previous nite. i got a response from someone who could look up the right info:

SW-12B Specifications



WOOFER: 12” Dual Voice-Coil (RW-12D or 122D2)

POWER HANDLING: 125 Watts/Coil

FREQUENCY RESPONSE: 29-100Hz

SENSITIVITY: 92 dB

IMPEDANCE: 8 Ohms/Coil

CROSSOVER FREQ: 100Hz with High-Pass Outputs

WEIGHT: 48 lbs.

DIMENSIONS: 13¼” X 25½” X 16¼”

MSRP: $320

CIRCA: 1990


so i NEED to find an 8 ohm 12 dual voice coil sub to make this work properly, correct?

That's hard to say. I'd first have to test the amp to see what load it could truly handle. I suspect you'd be okay with a 4ohm sub. But since your budget is low I'll need to look at budget drivers. What is your actual budget?

FYI you can sometimes get a 12.1 Infinity driver for around 50 bucks if you look hard enough.

 

[tonydahose]

That's hard to say. I'd first have to test the amp to see what load it could truly handle. I suspect you'd be okay with a 4ohm sub. But since your budget is low I'll need to look at budget drivers. What is your actual budget?

FYI you can sometimes get a 12.1 Infinity driver for around 50 bucks if you look hard enough.

truthfully around 50 bucks shipped..i have the stf-1 for my main room. when i do the addition i plan on making the kappa sub that is in the sticky, maybe two so the stf will go in the basement so this really is just an extra that is laying around and i thought what the heck.

edit: now you have me thinking aboout doing 2 subs for my main room. i just looked at the back of my receiver sony STR DB940 and it has an rca jack output for the sub and the other channels...if i used a rca y splitter could i send the sound to the stf-1 and the other box? would it degrade the sound to much by splitting? i could just wire it to the right positive and left negative of the bypass, right? or skip it and drill a small hole and wire it directly into the sub. or i could be completely wrong..lol

 

[lsiberian]

truthfully around 50 bucks shipped..i have the stf-1 for my main room. when i do the addition i plan on making the kappa sub that is in the sticky, maybe two so the stf will go in the basement so this really is just an extra that is laying around and i thought what the heck.

edit: now you have me thinking aboout doing 2 subs for my main room. i just looked at the back of my receiver sony STR DB940 and it has an rca jack output for the sub and the other channels...if i used a rca y splitter could i send the sound to the stf-1 and the other box? would it degrade the sound to much by splitting? i could just wire it to the right positive and left negative of the bypass, right? or skip it and drill a small hole and wire it directly into the sub. or i could be completely wrong..lol

Don't mix and match subs. It will do more harm than good.

Let's start with you searching your local craigslist. Shipping is what costs online. Look for any JL Audio, Infinity, TC Sounds, Audiopulse subs.

If you don't see anything then just see what you do have.

 

[tonydahose]

ok thanks for all the help. i just checked the amp that it will be pluged into, an old old panasonic receiver that has ribbon cable connecting it to the radio. it says 8-16 ohms. so i will be looking for an 8 ohm dual vocie coil sub. wish me luck

 

[highfigh]

thanks for all your help with this. when i called CV the tech said it wasn't listed in his computer. i had emailed the tech support the previous nite. i got a response from someone who could look up the right info:

SW-12B Specifications



WOOFER: 12” Dual Voice-Coil (RW-12D or 122D2)

POWER HANDLING: 125 Watts/Coil

FREQUENCY RESPONSE: 29-100Hz

SENSITIVITY: 92 dB

IMPEDANCE: 8 Ohms/Coil

CROSSOVER FREQ: 100Hz with High-Pass Outputs

WEIGHT: 48 lbs.

DIMENSIONS: 13¼” X 25½” X 16¼”

MSRP: $320

CIRCA: 1990


so i NEED to find an 8 ohm 12 dual voice coil sub to make this work properly, correct?

The dual VC design only uses the force from the second coil to make it work in a smaller box than using two separate woofers. As long as you find a woofer that will work in that enclosure and it's a good match for the sensitivity of your main speakers, it will be fine.

If you still have the old woofer, you may be able to have it reconed, too.

 

[tonydahose]

The dual VC design only uses the force from the second coil to make it work in a smaller box than using two separate woofers. As long as you find a woofer that will work in that enclosure and it's a good match for the sensitivity of your main speakers, it will be fine.

If you still have the old woofer, you may be able to have it reconed, too.

how would i wire it to the right and left speakers from the sub then? would i put both right and left from the amp into the passover and just not connect one of those channels to the sub? i hope i am making sense. the passover had 2 sets of positive and negative for both channels plugged into the sub. would i combine them after the passover and into the sub?

 

[highfigh]

how would i wire it to the right and left speakers from the sub then? would i put both right and left from the amp into the passover and just not connect one of those channels to the sub? i hope i am making sense. the passover had 2 sets of positive and negative for both channels plugged into the sub. would i combine them after the passover and into the sub?

Does the sub have an amplifier in it? If it does, the L & R signals are combined in the amp, so you don't need to worry about that unless the sub amp is actually stereo, which is unlikely. The general consensus for best use of dual voice coil woofers is to withe them in series or parallel and feed both voice coils the same signal. Not all stereo amps are perfectly time aligned, and if the signal from one channel is slightly delayed, phase cancellations will occur and that will cause all kinds of problems with the sound.

FYI- it's called a crossover.

 

[tonydahose]

duh, crossover..my bad, and no it is a passive crossover

 

[highfigh]

Can you post a photo of the sub's inputs?

 

[tonydahose]

Can you post a photo of the sub's inputs?

yep. so if i didnt go with a dual coil would i go right pos and left neg? or just pick one side and ignore the other?

thanks!

 

[lsiberian]

yep. so if i didnt go with a dual coil would i go right pos and left neg? or just pick one side and ignore the other?

It doesn't matter what you do as long as you run the positive power from your amp to the positive terminal on your driver. And vice-versa. You can use any wire you want in between. Though I do suggest you stick to standards and clip out the other wire for simplicity.

I'd actually wire one set to the other. In case you forget when moving or something like that.