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Discussion Starter · #1 ·
Hello,

It's been forever since I've been here! Well, I'm back and this time I'm getting serious with my sub designs. I went to the swap-meet (flea market) and picked up some more subs. I have a Phoenix Gold XMax 15" sub and a few others for cheap.

I'm trying to get the sub to play to it's Fs, 21 Hz, however, be it bandpass 4th or 6th order, sealed, bass-reflex, or horn designs, it always favors 60 to 70 Hz. Around 5 or 6 cubes is my limit, because of family acceptance factor.

At the moment, a horn design would do a lot for me as far as practice and experience goes. If I can create a decent folded horn, then that would be quite an achievement and I would learn a lot in the process.

It appears that the parameters of the driver seem to favor SPL over SQ, which I think is what this driver was built for. But that's not stopping me from making a sub that's both loud and LOW!

So an F3 in the low 20's is the goal.

Here's what I have so far...

Grey = bass reflex, 5 cubes @ 35 Hz
Yellow = sealed, 3 cubes (this sub has nearly the SAME response in 1.5 cubes and 5 cubes sealed)
Magenta = sixth order bandpass, 2.5 cubes @ 25 Hz & 2.5 cubes @ 50 Hz
Cyan = forth order bandpass, 1.5 cubes sealed & 4 cubes @ 30 Hz
capture16.jpg

And here's what I've been working on for the past few hours:
capture13.jpg
capture12.jpg

Here are the parameters for the sub:
Qes: 0.335
Qms: 6.380
Qts: 0.319
Fs: 21.81 Hz
Vas: 10.011 Ft^3
Sensitivity: 91.47 dB

Straight from the WinISD database.

So... what now? I'll keep trying but it feels like I'm going in circles with HornResp... does anybody know a different enclosure type I could try? Tips? Tricks?

Also, am I the only one who always feels like I'm forgetting something whenever I post a new thread?

Thanks in advance!
 

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Discussion Starter · #3 ·
Why yes, yes I have. I know how to use HornResp, I just, don't think this sub likes horns... either that or I need to try something else like, say, a tapped horn.

With this design I was hoping to fold the horn around the back of the throat so it looks like a traditional car audio l-ported box.

I'll try a tapped horn and see how it comes out. I've also tried a THT style horn with an offset driver, and a few others but I'll keep trying.
 

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I am still learning horns myself but I can try to help. Can you post a screen shot of the main
Hornresp page the design page?

Matt
 

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Discussion Starter · #5 ·
Here ya go!
capture14.jpg

I've changed it and experimented and this is where I am now.

Here's the response:
capture15.jpg

Not bad but the F3 is still way too high for a home theater/ground pounder. This is as low as I've been able to get it so far.
 

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Discussion Starter · #8 ·
Aww : (.

This is an SPL sub anyway, so to get the most out of it, I want high efficiency.

High efficiency = LOUD.

Loud = more headroom = SQ (or at least my logic says so).

I'm gonna try a bandpass in WinISD and fiddle with HornResp a little more.

Better yet, I could use HornResp to simulate a bandpass (I heard it's possible... not sure how though).

I'll post some results of more experimentation.
 

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I'm alittle late to the game, but - The X-Max subs work best in ported or dual passband boxes. I used to put them in 6th order boxes for insane bass in cars/ trucks when they first hit the market- I've tried a few different drivers through the years for horns and it seems the ones I have from car-fi days just don't like horns. (fs/qts should be a higher # IIRC, have to check my old notes) I too am "back at it" trying to do a horn (again) If I find anything useful I'll let ya know.
 

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Discussion Starter · #10 ·
I tried AkAbak! I'll post graphs tomorrow!

@Stereo_Dave: Nah, you're not late, I STILL haven't made a box yet. However...

I'm learning AkAbak, and trying it out is the best decision I've made for my knowledge of speakers.

Also, did you really use specifically Phoenix Gold XMax subs? I've never heard of them, when where they made? Around early 2000's I'm guessing...

Car subs aren't designed for efficiency, but for raw power. It's like comparing a high-end sports car with a semi truck. Both have exceptionally powerful engines, but one utilizes it for speed and the other has extreme strength at the cost of speed. Likewise, horns are efficient and loud, however, the more heavy-duty car subs make up for efficiency in extreme wattage handling.

Hopefully I can take into account the room around me so the sims in AkAbak are more accurate and the enclosure can cooperate with the environment around it. I need to learn how to properly use the Def_Reflector object in AkAbak though. Can't find much about it. I even got a trojan horse virus trying to look up such a discrete subject.
 

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I've downloaded AKABAK and havent played w/it yet- Been experimenting w/ Hornresp and finding out that most of what I "have laying around" won't make a good horn (at least one that plays low as I want it to.)
Yes, X-Max specifically - IIRC they were introduced in the late 90's? Just after the BIG watt power amps started to be popular, we were letting the smoke out of everything back then, this was one of PG's "solutions"- I never made a ported or bandpass box they didnt like ! AT any rate, I found some notes I was trying to reference.

From the Loudspeaker Design Cookbook (4th edition)
p16 EBP= Efficiency Bandwith Product = Fs/Qes = 50 or less suited for sealed, above 50 (100) suggests a ported.
Also P37 1.330"woofer selection" with bandpass enclosures, because of the increased trade off flexibility, the ratio of fs/Qts is important. Low ratios, generally yield lower f3 roll-offs.
What does this mean to horns ? I dont know, I'm not "there" yet. In my research of horns I came across this *** (2 x fs)/Qes= aproximate speaker resonant frequency ***
There are some really good write ups on hornresp on -line. As far as I can tell its pretty much - mess w/ it til it works out for you, settle for what you can get it to do, or pick a different driver. I know we all want the magic solution, but we all know there are trade-offs involved-
 

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Discussion Starter · #12 ·
That's really incredible that you were able to create a basic formula! :bigsmile:

As far as making a horn for my XMax, all I'm looking for is efficiency. The sub's sensitivity is 91 db/1w/1m, so I'm looking to beat that by a few db's in a passband of at least 10 Hz. Horns seem yield better response than either bandpass or ported boxes according to HornResp. I'll need to experiment and see what sort of crazy sub designs I can conjure up in Akabak :T!

It doesn't matter if I use bass-reflex, bandpass, or any other ported or horn-loaded design. All it has to do is be efficient and loud, but of course, sound good to me.


This is how I think we should all think of subwoofer enclosures, their drivers, and speakers in general. All part of a giant acoustic puzzle :).
 

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Discussion Starter · #14 ·
You should watch his other videos. He has a lot of interesting material on his YouTube channel. His pattern of thought is interesting, as he rationalizes very thoroughly.
 
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