After a year resisting, I finally gave up and got a 15" Magnum to run in my daily driver. Should have done it a long time ago, but you know how that can be. After the Magnums I've heard lately, I can't wait to get this put in this weekend and rocking in the Stratus. It's going in a little different box than most, so we'll see how it works out, but based on the specs, this flared slot chambered transmission line should work absolutely flawlessly, and be a low end monster while not giving up too much on the top end either.

I'll have to ride up to Mooresville and let Nick check it out and tell me what he thinks once I get everything worked out, and I'm happy with the enclosure.

That sounds very promising, cant really go wrong with the Mags from what ive heard period.

Very interested in the box design.

Hey man, glad to see you on the forum! (PS: your stickers are going out on Saturday) Definitely let the forum know how the enclosure works out with the Mag 15. Mag 15's are fantastic drivers, and when put in the correct enclosures can make for a wicked combination.

Here's what I was thinking on the box, small chambered transmission line, doing it in birch with some Stain and Poly, I think I'm going to do a grey stain and a lot of poly on this one, since it'll match my car well.

Flared slot chambered transmission line?

No offense meant to you at all, but who have you been talking to?

Do I need to break it down for you a little, so you can understand?

It's a flared slot port, that you can see in the picture, correct?

It is a transmission line, I will tell you that, since you can't see the inside of it, and it incorporates a small compression chamber, which changes the way it responds, quite favorably at that. I have been building these for quite a few friends for a while now, experimenting with the chamber size and line area and length, and have had very favorable results.

I think Jim's point (if he doesn't mind me speaking for him) was that one should be cautious to avoid over-adjectiving things. Some choose to over-complicate the title of every enclosure they make when the general function can be described very succintly with, say, the term "Transmission Line."

It'll be interesting to see the progress. The Mag is a very solid driver and when paired with a quality enclosure, I'm sure you'll have a very favourable experience.

KOO! Maggies are for pimps and hustlas!

And for those with superior taste and knowledge.

I think Jim's point (if he doesn't mind me speaking for him) was that one should be cautious to avoid over-adjectiving things. Some choose to over-complicate the title of every enclosure they make when the general function can be described very succintly with, say, the term "Transmission Line."

It'll be interesting to see the progress. The Mag is a very solid driver and when paired with a quality enclosure, I'm sure you'll have a very favourable experience.

I understand your point, but on some other forum (I know this one is a bit more knowledgeable), I tried to do that, and was rudely responded to that "That's not a Transmission Line", so I tried to describe what I was doing a little more, but I guess I failed miserably at that.....lol

I think Jim's point (if he doesn't mind me speaking for him) was that one should be cautious to avoid over-adjectiving things. Some choose to over-complicate the title of every enclosure they make when the general function can be described very succintly with, say, the term "Transmission Line."

It'll be interesting to see the progress. The Mag is a very solid driver and when paired with a quality enclosure, I'm sure you'll have a very favourable experience.

I understand your point, but on some other forum (I know this one is a bit more knowledgeable), I tried to do that, and was rudely responded to that "That's not a Transmission Line", so I tried to describe what I was doing a little more, but I guess I failed miserably at that.....lol

You just have a string of bad luck then...lol. F em...just build it and let us know how you like the sound.

devildriver, since I've seen you post around, and know you know what you're talking about, here's a quick sketch of what I'm planning, the dimensions and scale aren't right, this is just a sketch to give you an idea of what I'm playing with. I've done them for other subs before, and they sounded great, just have to play around with the specs for the Mag tonight, so I can build it tomorrow.(MDF first, until I'm happy with the sound and tuning), Tell me what you think of the concept. To me it seems that compared to a ported box, you get a much wider range of useable frequencies without the nasty peak associated with a ported box, and you get increased power handling as compared to a standard transmission line, and by using a small compression chamber, you can keep the enclosure to a more manageable size. Of course, every corner will have a 45 in it to maintain the line area all the way through.

Edited September 28, 200717 yr by stratusrt01

I'm at work so I can't see any pictures except from an extremely limited number of servers, but I can make some guesses and confirm some things you've mentioned.

The really big advantage of a TL, to me, is that unlike a bass reflex enclosure, a TL will perform very well and consistently in many situations. Any bass reflex enclosure is very sensitive to mistuning. This directly relates to power compression: when you apply power to the coil, the resistance increases. If you've got it warm enough to double DC Re (which isn't at all uncommon), you've also doubled Qes and Qts and, thus, your bass reflex (or virtually any ported enclosure) is considerably out of tune. This can be a bad thing, particularly when we're talking about a sub in a car where most users tend to want to put every watt possible through the coil even if there's no real output being gained.

So naturally, it tends to be less peaky, which means the usable bandwidth is extended by interpretation (if there is no peak from which to judge upper and lower extension, then it sounds to us as if great extension exists). Also, excursion tends to be a little more controlled in a TL, so you naturally have more mechanical power handling. I, personally, have never cared about dumping a lot of power into a coil: it usually sounds much less pleasant than staying well within thermal limits, particularly if the other aspects of power compression (BL and Cms) are accounted for in the design of the sub. Not everyone subscribes to this, mind you.

As far as compression chambers go, I've never used one in a subwoofer before for any enclosure design. The advantage is that you can typically cut down line length and total size by a bit, but the disadvantage may be that you have frequency response aberrations to deal with. I would guess that in a subwoofer, their impact would be relatively slim by comparison to the great power your transfer function holds over the final result.

very informative, you just gave me a logical explaination to what I experienced real world with testing and playing around. Kind of gives credibility to what I was thinking was going on.

Looking great again Rich keep up that great work. One day maybe I can design enclosures as good as you.

Do I need to break it down for you a little, so you can understand?

It's a flared slot port, that you can see in the picture, correct?

It is a transmission line, I will tell you that, since you can't see the inside of it, and it incorporates a small compression chamber, which changes the way it responds, quite favorably at that. I have been building these for quite a few friends for a while now, experimenting with the chamber size and line area and length, and have had very favorable results.

Are you mass loading the line at all?

Just seems awfully short for a non-loaded line...considering you're looking at 14 feet or so of length, easy.

But I know nothing about these things

OK, here's the quick calculations I came up with.

chamber size - 1.65 cubic ft before displacements

line length - around 94"

line area - around 70"

quick guesstimate is that it should be tuned to around 32-33hz

by all conventional thinking, anyone looking would think I'm crazy, it's going to sound like crap, etc etc. I will let others decide when it's done.

Edited September 29, 200717 yr by stratusrt01

You're using that TTB design you for THE 3515/9515?

THE version you build looks absolutely amazing.. fyi.

No, the calculations don't quite work out right for the Mag, so I had to recalculate it. The chamber had to be enlarged a little, and the line length extended to lower the tuning. I don't want the Mag tuned to 37hz, it deserves better than that......lol

Edited September 29, 200717 yr by stratusrt01

No, the calculations don't quite work out right for the Mag, so I had to recalculate it. The chamber had to be enlarged a little, and the line length extended to lower the tuning. I don't want the Mag tuned to 37hz, it deserves better than that......lol

True ****.

Nice sub & box.. throw some vids up of that thing smashing lows.. you know it's good for it.

How much will those take daily?

Edited September 29, 200717 yr by J31Rob

They're rated at 950rms, but I'll be giving it an SAZ-1500 daily. I'm not really hard on subs, and from what I've heard, if you're not an idiot about it, 1500rms is no problem on it.

They're rated at 950rms, but I'll be giving it an SAZ-1500 daily. I'm not really hard on subs, and from what I've heard, if you're not an idiot about it, 1500rms is no problem on it.

Yeah.

Can't wait to see it go in.

Got the box built and the Mag in the car, had to go get a few things, so I couldn't hook up the SAZ-1500D, but we wanted to hear whether the box was worth anything, so we fired it up on the rear channels of the SAX-100.4. Wasn't expecting too much, seeing it was only getting 320 watts, but we both kind of just looked at each other and said "What the Hell?" Much more output than we expected at that power level, so I went and got the few things I needed, and I'm going to hook up the 1500D here in a few minutes, but from the initial listening on low power, it seems like it's going to be what I wanted, a low end monster and very smooth sounding.

More updates later tonight.

When you're done and satisfied with the results, please get with me about specifics about the enclosure. I'd be interested in adapting it for a 12" mag to try.

that looks exactly like a box i built for a friend. not quite as pretty but it was 1.4 cubes for 2 12's with something like a port length of ~68 and a port size of almost 50 sq in.