Copying older Polk Design

vinkalmann

Hey guys,

I'm hoping some of you Polk people here may be familiar with a Polk sub design from yesteryear. I purchased the sub around 10 years ago but I don't remember the model name other than it had C4 components and I *think* may have been "ex". The sub was driven by four 6x9 speakers. It had to a total of four chambers inside, with the 6x9's being driven opposed in pairs. Each of the pairs was wired out of phase in a push/pull design. The sub was recently stolen and I am really sad because I loved that thing. TIGHT bass and didn't take a lot of room. Does anyone know what it was? The pic below is how the design looked (yes picture is ugly!)



My second question is this. If I wanted to build a sub this time, I know that they volume of the space on the outer chambers needs to be precise, but does the volume of the inner chambers indicated by the arrows matter as much since it's closed off?

Thanks in Advance!!

Matt

ben62670

I remember that sub. It was more like 15-18 years ago! I wanted one for my 80 RX7 in the worst way. With the newer subs you are better off just building with a new single driver. There is a reason why it didn't last too long. Not trying to pick on you here, but those may have had a good punch, but were lacking down low.
Keep us posted on your new design.
Ben

vinkalmann

Cool man, thanks for the response. I would bet you're right about the lacking low end. I think it was enough for me since I wasn't really trying to blow the doors off. I do indeed want a bit more now though .

Do you think that making a dual band pass design from the Polk site with 2 10in subs will give me good/enough low-end? I'm looking for a compromise between sound and the space that the box will consume.

This would be run using an Alpine PDX amp (150Wx4) with two channels being bridged for the sub. The fronts are MB Quart components.

Thanks for your time!

ben62670

vinkalmann wrote: »

Cool man, thanks for the response. I would bet you're right about the lacking low end. I think it was enough for me since I wasn't really trying to blow the doors off. I do indeed want a bit more now though .

Do you think that making a dual band pass design from the Polk site with 2 10in subs will give me good/enough low-end? I'm looking for a compromise between sound and the space that the box will consume.

This would be run using an Alpine PDX amp (150Wx4) with two channels being bridged for the sub. The fronts are MB Quart components.

Thanks for your time!

I am guessing by the age of your old woofer you are at least 30. I have heard plenty of subs around. You are probably more interested in good tight base in a small space. We need to know if your amp is 2 ohm stable when bridged. One of the best sounding(as in tight punchy base)was a pair of 10" Polk's sealed with 220 watts of Nakamichi power going to them.

Keep us posted.
More info is more replies.
Ben

neomagus00

if you're concerned about space, you do not want to go bandpass... they're huge and, as a rule of thumb, sound bad. sealed is the smallest, ported next, and depending on what you put in it, either can work very well (my sub is in a sealed box right now, but i can just feel its desire to have a port...)

since your amp is not likely to be stable to 2 ohms bridged, that means you have 300 watts to play with. the momo 10 fits that bill quite well, and fits in a rather small sealed box to boot.

i presume you're looking for good quality, rather than high volume?

Jstas

The sub was the Polk Audio C-4. That was the sub and IIRC, the 6x9 woofers were the woofers from the Mobile Monitor series.

I should honestly go look. I have one.

You can find them too, on eBay. Mine is being used in a home theater because it fit neatly under the couch.

neomagus00

Jstas wrote: »

Mine is being used in a home theater because it fit neatly under the couch.

curiosity: can it get low enough for 'real' HT, or does your situation (budget, environment, personal preference) not allow that?

Jstas

What do you mean "low enough"? The thing digs down into the low 20 Hz range and has resonances into about 17-19 Hz so it'll still shake your butt. How much lower do you need it to go?

neomagus00

Jstas wrote: »

What do you mean "low enough"? The thing digs down into the low 20 Hz range and has resonances into about 17-19 Hz so it'll still shake your butt. How much lower do you need it to go?

none... that answers my question

(16 Hz would be nice...)