...in need of enclosure advice regarding 15-inch woofer

**Tattz** · **06-08-09, 04:10 PM**

Hi all, this is my first post on these forums.

I have recently purchased a 15 inch subwoofer from The Source (formerly RadioShack) which of course came with no thiele/small parameters or anything that would help me determine what kind of enclosure would best work for it. I called both customer service and their distributors, and nobody had any information on even a user manual for this thing.

As a musician, i require good spl at 24hz and up...ideally if I can achieve good volume at 20hz then I'd be happy. Also I'm aiming for a good flat response across the bass frequency spectrum.

Here's what information i can provide about the driver. It's rated at 100watts of RMS power at 8 ohms impedance. It has 29.9oz magnet, it's supposed frequency response is 25hz-2khz (though i've tested it with a full frequency sweep and it goes down to 1hz without any distortion or clipping problems). Oh yeah, and the cone material is polypropylene.

On the Source's website, a user suggested a 7 cubic foot enclosure (though he didn't specify whether it should be ported or sealed), and my original plan was to go for a sealed enclosure since those tend to provide the flattest bass response.

Also, if it helps, the room it'll be in (my studio) is very small, about the size of a small apartment's bedroom.

Any help or advice would be deeply appreciated. Thank you in advance for you time.

**fredm** · **06-08-09, 04:16 PM**

I don't think 100RMS is going to get you flat to 20Hz or even 25Hz. My advice is another driver or bolt it into a box and go from there.

This looks like the same specs

http://support.radioshack.com/suppor...oc60/60539.htm

Found it here

http://support.radioshack.com/produc...5&Name=speaker components&Reuse=N

**Tattz** · **06-08-09, 04:26 PM**

I see. what driver would you suggest I look into. Any examples you can recommend? I bought this driver dirt cheap, and I'm selling quite a few speakers, so I'm open to the idea of buying a new driver anyway.

**Tattz** · **06-11-09, 10:44 PM**

wow...thanks for the help, everyone. 43 visits to this thread and counting and nobody else has anything to contribute

**Mike P.** · **06-11-09, 11:03 PM**

Been busy. What would you be willing to spend for a sub and an amp?

**Tattz** · **06-11-09, 11:09 PM**

What is the least expensive option, I suppose. I'll save up if I need to, and like I said, my room is very small and i'm gonna be here for a few years, but I'm still attending university, so i doubt I'll really need that much power to fill up the room with sound. i just need to reach that 24 hz . My instruments are tuned low since I have 7-string guitars and equivalent basses. my G flat translates into 24 hz.

**Mike P.** · **06-12-09, 10:05 AM**

What guitar amp do you have? Subs are usually 80hz and down, is that what you're after?

**dgilme** · **06-12-09, 10:50 AM**

I'd suggest this 15" woofer:

[img]http://www.pdphoto.org/jons/pictures..._bg_111701.jpg[img]

**Mike P.** · **06-12-09, 11:12 AM**

Quote:

http://www.pdphoto.org/jons/pictures..._bg_111701.jpg

Bad link.

**SteveCallas** · **06-12-09, 01:03 PM**

Quote:

Tattz wrote:

though i've tested it with a full frequency sweep and it goes down to 1hz without any distortion

No.

What specifically is your budget? Exodus 15" for $140 is probably one of the better deals out there at the moment.

**Tattz** · **06-12-09, 04:46 PM**

I can certainly swing $140. Exodus brand, you say?

and Mike P, my system is a home studio. I have the bass hooked up directly into the mixing board post FX. Basses can get as high as 125hz or so, but mine, as I said is tuned to a low G, which is equivalent to 24hz.

**fredm** · **06-12-09, 06:24 PM**

i think Mike was talking about you claiming the driver goes to 1 Hz distortion free.

Off-topic (but I guess it is what you want to talk about) I play guitar and don't see any reason to tune that low. Bass amps cannot reproduce that at all. A 5 string bass tuned 2 full steps down seems over the top. You are never going to get the volume for anyone to hear anything you are doing with that, especially at a concert. They will hear the high frequencies from the string if you pop it, but that is about it.

**Tattz** · **06-13-09, 12:59 AM**

my appologies in advance for any spelling/grammar/logic hiccups in the following reply, i'm running on little sleep at the moment.

My guitars are just one tone lower than Korn's 7-strings, and same goes for the bass. Yes, I suppose that it's pushing things, but that's part of my sound. I don't think a step lower than Korn is that extreme.

If you're referring to the physical capabilities of bass cabinets to reproduce 24hz, then I can see why you'd doubt that they can reproduce that, but then again, I never trusted speakers that come installed in any amplifier or cabinet. Call me crazy but, at least for guitars, a bunch of midrange drivers will never be able to reproduce the richness of a guitar's tone that a multi-way sound system can, especially if the drivers are microphoned. Live venue subwoofers are usually 18-inch and there's at least 8 of them (for small venues). Those would be able to create good SPL at 24hz, but not below.

But I digress:
When we're talking about bass below 90hz or "sub-bass", there is a common misconception that the human ear can actually hear any of those frequencies. What actually occurs is our eardrums stop hearing the actual frequencies, but begin to "feel" the sound. That causes a perceptive illusion of sound, which is no more than the organism's natural reverberation at best. Our love for these frequencies, thus, come from us being able to "feel" the frequencies, and their subsequent effects on the physical and emotional states of the listener, hence my specific interest in the 24hz threshold.

I do plan on doing research on a few options of drivers for this project, so any suggestions would be wonderful. Also, is there any way that a sealed box would aid the driver's performance, or do I need to become more acquainted with ported enclosure designs?

**philcav7** · **06-13-09, 08:14 PM**

If I am not mistaken, the lowest note of a naturally tuned 4 string bass is 41HZ, are you saying that you are using a 4 or 5 string bass? I just would have never imagined that a 5 string bass, tuned down two steps, would be 24Hz....Crazy.

Sorry for going off topic.

**fredm** · **06-13-09, 09:58 PM**

Quote:

Tattz wrote:

My guitars are just one tone lower than Korn's 7-strings, and same goes for the bass. Yes, I suppose that it's pushing things, but that's part of my sound. I don't think a step lower than Korn is that extreme.

If you're referring to the physical capabilities of bass cabinets to reproduce 24hz, then I can see why you'd doubt that they can reproduce that, but then again, I never trusted speakers that come installed in any amplifier or cabinet. Call me crazy but, at least for guitars, a bunch of midrange drivers will never be able to reproduce the richness of a guitar's tone that a multi-way sound system can, especially if the drivers are microphoned. Live venue subwoofers are usually 18-inch and there's at least 8 of them (for small venues). Those would be able to create good SPL at 24hz, but not below.

Korn uses it mostly for the slaps to create the treble sounds. Those 18" subs likely use a 30Hz high pass filter to avoid damage.

**GPM** · **06-14-09, 11:15 PM**

Quote:

fredm wrote:

http://support.radioshack.com/suppor...oc60/60539.htm

Greets!

400-1035 measured specs from ~ a decade ago, but have no idea if they're relevant today:

25 Hz Fs
12.25 ft^3 Vas
11.7 Qms
0.87 Qes
0.81 Qts
7 ohms Re
132.73"^2 Sd
0.19" Xmax
3.3 mH Le

Anyway, we're talking at least a ~17 ft^3 cab to get this driver to 'be all it can be' down into the 20s even with a small room's gain..........

GM

**Ricci** · **06-15-09, 09:18 AM**

Tattz,

That Radio Shack is not going to do any justice to 25hz material IMO.

Can you clarify a bit here? Are you going to be playing live bass or guitar through the proposed cabinet? Will you gig through it at all, or is it just for a music listening / studio monitoring type of set-up in which you will run your own downtuned music through and leave it in the house?

What's your budget for a different driver, does it have to be 15" and what is the intended range it will cover (related to paragraph 1)? 24-120hz, or do you need it to cover a wider range like 24-3khz? Basically will it be X-overd?

**GPM** · **06-15-09, 05:01 PM**

Quote:

Ricci wrote:

That Radio Shack is not going to do any justice to 25hz material IMO.

Greets!

You'd be surprised what it can do in a max flat impedance TL and some low end room gain, but as I said, the trade-off is a huge cab.

GM

**Tattz** · **06-16-09, 03:08 PM**

fredm, Korn's bassist does do a lot of slap, but he also plays the bass, and i can name tracks in which he does so all the way down to that low A tuning.

GPM, thanks for the help, much appreciated. I'll plug those parameters into Winisp and see what it gives me. also, i don't care how big the enclosure it has to be, i'll make space for it.

ricci, glad to clarify. I will not be using the woofer live, this is just for my studio monitoring/ recording. I will be touring, but until I can afford the system I need for good live results, I'll be sadly depending on the specific PA systems that'll come wiht each venue. Sad indeed, the bass will be severely damaged live, but that's what i gotta live with until my next album's release.

I'm selling a bunch of speakers, so my budget for a new driver lies within the 150 to 200 dollar range. I also have in my stash a rockford fosgate...(checking brand)...rfp3812 12'' car subwoofer. All I know is that 15 inch woofers are much better at reproducing the lowest of the low than 12 inchers, on average, thus why I went for that size, but i'm here to learn, so correct me if i'm wrong. I didn't plug the fosgate in winisp...would it be a better option for this project than the 15 inch driver? Also 24 to 120 is the perfect range I need it to cover.

**Ricci** · **06-16-09, 03:41 PM**

Do you care how big the enclosure is? Can you put a maximum external size that you would like to stay at? What will you be using for amplification?

For maximum bang for the buck and since it's relatively easy you should probably go ported. For a range of 24-120hz and your likely listening habits, a Peavey LoRider 18 would fit the bill. It's an 18" driver and you wanted a 15" but for bass more really is more. May as well go all the way. I'll have to model up a box alignment later. The plus is if you build it right you could use the same cab for gigs, practice, moderate PA subwoofer duties, etc. Multi use FTW.

**Tattz** · **06-16-09, 03:50 PM**

ideally 2ft cubed is what i can be comfortable with, but i'll handle it if it's bigger. I have a 120w woofer amplifier handy for amplification.

Multi-use is always a good thing, but i'll sacrifice that as long as it does a good job in the studio. Just for the record, my studio is about 30 feet by 10 feet.

**Ricci** · **06-16-09, 04:02 PM**

Ok. Since you have a large room and your power amp is conservative at 120w that makes me think that the LoRider 18 really is a good choice for you. It's efficient so it'll still get loud off of that 120w and it should have great SQ due to a light moving mass and very low inductance. I understand that it's right at the limit of what you wanted to spend on a driver but it's a solid piece that should last you for years.

A 2' cube is about 6cu ft of usable volume for the driver. I think with just increasing that a little bit you'll be in fine shape. I'll model something up later.

**GPM** · **06-17-09, 01:22 AM**

Quote:

Tattz wrote:

GPM, thanks for the help, much appreciated. I'll plug those parameters into Winisp and see what it gives me. also, i don't care how big the enclosure it has to be, i'll make space for it.

Greets!

You're welcome!

Hmm, my experience with this driver is that except either in a small room or possibly EQ'd ~flat in a corner, a typical BR or sealed alignment isn't going to do the 20s well as Ricci noted. TL is pretty much it IMO. Also, now that we know the room is 30 ft long, its 1st axial mode will be around 19 Hz, so no room gain of note to help the TL's sagging response in the 20s, making the LoRider in a 4th order band-pass (BP) a much more viable choice and it will be a bit smaller at only ~11 ft^3.

GM

**Ricci** · **06-17-09, 11:44 AM**

With the Low Rider 18 a vented box of 10.0cu ft net volume tuned to 25hz with an 8" port 15.7" long looks pretty good. That'd be a box of about 24"x24"x39" external to end up with that volume after driver port and bracing displacement. It is about -6db down at 27hz and should do about 110db or more from 24hz on up in your room with 120w. You'd want to use a 20hz rumble filter with it. Later on down the road you can up the power to about 350 or 400w to add about 4db more headroom.

**Tattz** · **06-22-09, 07:25 PM**

hmm it looks like I'll have to do layering of the bass response in the studio for this album. I have no way of building this kind of system for now.

Rici, this configuration, will it be usable in small live venues, or is your suggestion purely for my room's configuration? I'm asking because, if I put this project off for next album's release, i want to know how dynamic this setup will be in different indoor settings.

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