Newbie Sub Questions

[demondo]

Hi folks.

The fact that this is my first thread here probably means your all way ahead of me at speaker design. I will get right to the point.

Obvously I am building a subwoofer.I am using components I picked up fairly rock bottom, but which should suffice for my purposes if I can somewhat optimize the configuration.

I picked up a mission 10" part # LF-21083/M7 sub driver. Reviews were not scathing , but for a meagre 30 bucks, hey, I figure it's worth a try. This link gives an idea of the item itself.

http://cgi.ebay.ca/ws/eBayISAPI.dll...EWN:IT&viewitem=&item=170095821355&rd=1&rd=1.

(Sorry for that, my posting skills are somewhat lacking.)

I also corralled a Cerwin-Vega CT-10D subwoofer crossover which supposedly has a range of 120Hz and below. I would like to port this, and drive it with a Pioneer SX-950 receiver on the B channel.

What do you think? Here is a pic of the crossover, any suggestions as to cabinet configuration and size would be extremely helpful.

The crossover has two sets of wires which puzzles me, thinking perhaps they are meant to run parallel drivers?)

I look forward to any and all responses, even good-natured ridicule will suffice. LOL

Regards,
Demondo

 

[MJL21193]

Hi. Are you able to test it to determine the T/S specs.? Without this it will be difficult to design a proper sized box.

 

[demondo]

I don't have any test equipment available, the only spec on the eBay listing was a DC resistance of 3.2 ohms. After that, I know less than nothing. I'm flying by the seat of my pants here I'm afraid. LOL

 

[djn]

Hi Demon, you should contact the manufacture for the T/S specs. That will allow you to design the proper cab for your sub. Here is their website. Cheers..

http://www.mission.co.uk/

 

[demondo]

I will do what I can, thanks for the link.

 

[demondo]

I had said I posted a pic of the crossover, just so you know I know the differemce , LOL, here's the proper pic.

 

[demondo]

Still no word from mission. Is there any way to build the box a bit larger than a 10 inch driver would dictate, and then add material to the inside of the box in some form or another to "tune" it?

I know it sounds hokey , but without specs, or equipment to acquire same specs, this project is at a standstill.

Trial and error vs science?

Demondo

 

[richie00boy]

That's a passive crossover. Really it's not going to give you very good results with your drive unit and box. Build something and have fun but next time try and do some research before you buy

As for the drive unit, best best would be to copy the box design that Mission did.

 

[MJL21193]

Still no word from mission. Is there any way to build the box a bit larger than a 10 inch driver would dictate, and then add material to the inside of the box in some form or another to "tune" it?

I know it sounds hokey , but without specs, or equipment to acquire same specs, this project is at a standstill.

Trial and error vs science?

Demondo

You could start with a 30 litre box, with a removable back. If you find it's too big, you could reduce the box size by cutting the box smaller (as in not as deep from front to back). This would work ok for sealed box, but you want ported, right? That would be more difficult, as without the specs, the port length and diameter can't be accurately determined. You could go with 2" PVC pipe cut to different lengths to try to find the best bass response in the 30 litre box.
If you knew the size of the box the driver came out of in the first place, that would help.
If it were me, I'd build a transmission line box for it, ballpark the Fs at around 40Hz. This would give good results, as the TL is not as picky about driver specs.

 

[demondo]

Moving right along. Sort of.

I have built my box; I based it on the box that the actual driver came out of. At least the driver looked the same; same size, same appearance. Shouldn't be too much of a shot in the dark. It is a downward firing box, 400x365x416. I did not port it as I originally had planned, the Mission sub did not seem to be ported.
I have mounted the crossover, which came from a Cerwin Vega HT-10D subwoofer. It has two pairs of wires, which I am not quite sure how to deal with. I also have a Kenwood KA-5700 integrated amp which I am thinking of using in conjunction with the Pioneer SX-950 reciever (pre-out function) to drive the sub.

Will this even work? I don't know, that's what I am asking you fine folks.

Any wiring schematics, set-up for the amp and reciever, etc., would be greatly appreciated.

So far the biggest revelation after all of this for me would be the fact I really need a router. In-laws are quite handy in times of need.

Looking forward to your replies.
Demondo.

 

[richie00boy]

As you are using a dedicated amp for the sub, your best bet by far would be to put an active low-pass filter between the pre-out and amp. The passive filter you have will be not much more than useless and rubbish.

 

[demondo]

Can you be a little more specific, perhaps a diagram or an appropriate link?

Remember, before you say demondo, say greenhorn, newbie, or audio diy defficient.

 

[demondo]

Complete?

I went with my original plan, and used the B channel of the pioneer sx-950 receiver to drive the thing. Sounds pretty good to me. I may experiment a bit, if anything it sounds a bit "loose". Perhaps some foam in there for damping purposes? Anyway folks thanks for all suggestions, all food for thought, and for future endeavours, valuable input.

Regards.

 

[Sonusthree]

Re: Complete?

I went with my original plan .......... if anything it sounds a bit "loose".

Hi,
Did you use the passive crossover? That may account (partly) for the looseness you mention. Passive crossovers also eat up valuable power. An active crossover/ low pass filter would be a step in the right direction and as a bonus your amp will effectively present more power to the driver, have more control and be easily tweakable to blend with your system!

You could just buy an 'off the shelf' filter but they are quite easy to DIY if you're up for the challenge.

I'll dig out some links if you're interested.

Regards,
Martin.

 

[demondo]

I was actually thinking of installing this.....

http://cgi.ebay.ca/EOSONE-POLK-1RF0...yZ67786QQssPageNameZWDVWQQrdZ1QQcmdZViewItem.

I had a whack of DAT tapes, and it seems like suddenly I have a bit of extra cash. This would probably be a good way to go, or at least better, correct?

 

[demondo]

There is also a 215 watt version. Whaddya think?

 

[Sonusthree]

That link shows "Page Not Responding" for me.

Is it a plate amp (specially for subs with integral crossover and possibly phase adjustment) or a regular amp (you would still need a crossover)?

 

[demondo]

It is a plate amp , apparently designed by eosone for a polk audio sub. The link I sent was for a 95 watt unit, but I am entertaining the 215 watt option. My reciever is 85 watts/channel.

The link seems to work from this end, not sure why it does not there.