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View Full Version : Potential box design for an XFL 15"



RSDXzec
05-16-2013, 09:36 AM
I currently have 3 Soundstream Picasso 12"s on a box I built myself a year ago (5.5cf 32hz 52sqin port) and have been told by many my port area is ridiculously small which I agree with. Rather than just build a new box for them I've decided to upgrade to an XFL 15". My current thoughts now are 4 cubes tuned between 30-32hz with 64 square inches of port.

What I don't like about my current setup is that the subs face the back and are pretty much on display as it's a hatchback. So I'm hoping to go with a downfiring setup, but while I'm at it go with a horn type design. I've done calculations to see if the sub is suitable for a downfiring setup and with such a stiff suspension it's fine. This is a general idea of what I'd like to do.

http://i41.tinypic.com/2nuueye.png

Would this be very hard to do? I'm hoping to have around 4" breathing space for the port at the minimum then go increasing in size. I'm really just after thoughts on this design and any tips I should take into account for example the angle of the horn coming up. Which btw the larger end will be facing the driver so the port exit will be at the far back of the car.

Cheers.

RSDXzec
05-17-2013, 03:13 AM
Anyone got any tips for this design?
Like how tuning may be affected by doing this... I'd need a horn decent angle not to...

Better-Action
05-19-2013, 08:52 PM
No ones got anything?

Surely box designers could throw some input in.

RangerDangerV2
05-19-2013, 09:12 PM
have fun with the tapped horn thing. LOL going to be lots of testing/math if you want to get a good response. but if you can make it work, then props

SounDrive
05-19-2013, 09:20 PM
A 4th order would be much easier to design and be very loud.

RangerDangerV2
05-19-2013, 09:23 PM
A 4th order would be much easier to design and be very loud.

not as loud as a correctly built tapped horn.

SounDrive
05-19-2013, 09:29 PM
not as loud as a correctly built tapped horn.

Key word correctly. It would be a PITA

RangerDangerV2
05-19-2013, 09:31 PM
Key word correctly. It would be a PITA
so? would be a great learning experience. and loads of potential with a horn design. they can play a very wide bandwidth play it very flat. also, they can be very loud because they are so efficient.

SounDrive
05-19-2013, 09:35 PM
so? would be a great learning experience. and loads of potential with a horn design. they can play a very wide bandwidth play it very flat. also, they can be very loud because they are so efficient.

If he's up for all the work, by all means he can go for it. The advantages over a 4th order aren't worth the trouble IMO, but that's just me.

RSDXzec
05-20-2013, 05:31 AM
A 4th order would be much easier to design and be very loud.

Whats a good way to design one? I'm willing to make the box bigger if it's 4th order because getting the sub out of the box would be a PITA (one of my goals here is to hide the sub so that works out great).
I've tried on winisd but I'm not getting a great response from it...

also wouldn't this be better in a 6th order? since it's made for ported I figured having a port in the rear chamber would make it feel at home.
I've also read since the suspension on these is so stiff they're really bad for bandpass right out of the box so i'd give it some "break in" time free air to loosen up the suspension before i do it.


so? would be a great learning experience. and loads of potential with a horn design. they can play a very wide bandwidth play it very flat. also, they can be very loud because they are so efficient.

Don't tapped horn designs require a lot of space?

oxsign
05-20-2013, 07:40 AM
Any reason you didn't do the port like this?
http://i629.photobucket.com/albums/uu13/amychrista_2009/2nuueye_zps6afdab9d.png (http://s629.photobucket.com/user/amychrista_2009/media/2nuueye_zps6afdab9d.png.html)

Don't know if it would make a difference, but my thought would be that air would flow a little easier without that 90* bend. Just a thought, I could be completely wrong here, lol.

Better-Action
05-20-2013, 08:19 AM
One idea is making just a normal upfiring ported enclosure with a false wall. Get some acoustically transparent material and go to town. Would keep the sub hidden and also be much easier to build. Would look pretty nice to if you put the time in.

Just a thought.

Anyone done a xfl in a 4th or horn?

RangerDangerV2
05-20-2013, 08:30 AM
screw it... either go quasi 8th order or ABC enclosure.

SounDrive
05-20-2013, 08:47 AM
You could always down fire the sub with the port firing back if you absolutely had to.

RSDXzec
05-20-2013, 11:14 AM
Any reason you didn't do the port like this?
http://i629.photobucket.com/albums/uu13/amychrista_2009/2nuueye_zps6afdab9d.png (http://s629.photobucket.com/user/amychrista_2009/media/2nuueye_zps6afdab9d.png.html)

Don't know if it would make a difference, but my thought would be that air would flow a little easier without that 90* bend. Just a thought, I could be completely wrong here, lol.

You are correct, I just thought it would be a pain to cut more wood on angles lol, but after this discussion I don't think I'll be going with that design.


One idea is making just a normal upfiring ported enclosure with a false wall. Get some acoustically transparent material and go to town. Would keep the sub hidden and also be much easier to build. Would look pretty nice to if you put the time in.

Just a thought.

Anyone done a xfl in a 4th or horn?

That is an awesome idea, just need to figure out where to get some and if I can get the same colour as the rest of the cars carpet (kindof a light brown)

I'm really looking forward to further suggestions on 4th or 6th order designs though because this thread has seriously got me started looking at those type of designs... I wouldn't mind having a box with 2 wooden holes facing up...


You could always down fire the sub with the port firing back if you absolutely had to.

Problem with that is both space and port breathing space, I don't have a lot of room to work with.

Thanks to suggestions I'm keen on both the bandpass designs and the acoustically transparent material as a last resort or maybe as an addition to it to even maybe hide the ports lol. I really like the hidden + security factor of the bandpass design. I only show a few good mates what I have in my boot ;) even though currently it's only 3 soundstream 12"s which aren't worth much lol.

SounDrive
05-20-2013, 02:14 PM
You are correct, I just thought it would be a pain to cut more wood on angles lol, but after this discussion I don't think I'll be going with that design.



That is an awesome idea, just need to figure out where to get some and if I can get the same colour as the rest of the cars carpet (kindof a light brown)

I'm really looking forward to further suggestions on 4th or 6th order designs though because this thread has seriously got me started looking at those type of designs... I wouldn't mind having a box with 2 wooden holes facing up...



Problem with that is both space and port breathing space, I don't have a lot of room to work with.

Thanks to suggestions I'm keen on both the bandpass designs and the acoustically transparent material as a last resort or maybe as an addition to it to even maybe hide the ports lol. I really like the hidden + security factor of the bandpass design. I only show a few good mates what I have in my boot ;) even though currently it's only 3 soundstream 12"s which aren't worth much lol.

What do you mean by not having space or port breathing space? A ported enclosure would be much smaller than a 4th order in most cases. And your port ideally should be around 4-6 inches from a surface in your car to load off of it.

Buck
05-20-2013, 05:18 PM
Meh, horns in cars are cool, but not really that great in my opinion. I would do a ported or 4th/6th depending on t/s parameters. Ported is going to be the best option most of the time, just regardless.

---------- Post added at 04:18 PM ---------- Previous post was at 04:17 PM ----------

You don't have to give up ridiculous space and test and cut all those crazy angles and pay 50+ for a design like that.

SounDrive
05-20-2013, 05:21 PM
Meh, horns in cars are cool, but not really that great in my opinion. I would do a ported or 4th/6th depending on t/s parameters. Ported is going to be the best option most of the time, just regardless.

---------- Post added at 04:18 PM ---------- Previous post was at 04:17 PM ----------

You don't have to give up ridiculous space and test and cut all those crazy angles and pay 50+ for a design like that.

This man knows what he's talking about

Buck
05-20-2013, 05:25 PM
I don't design horns, rear loaded horns, etc. (at the moment, working on it), but I know the space they require and their drawbacks. PWK and I talked about that a long time ago, ported boxes are just usually the way to go. You can customize them to do anything you want mostly, so that's what I "specialize" in. It's what performs.

I do like my occasional 4th and 6th order bandpass, don't get me wrong.

RSDXzec
05-21-2013, 03:51 AM
What do you mean by not having space or port breathing space? A ported enclosure would be much smaller than a 4th order in most cases. And your port ideally should be around 4-6 inches from a surface in your car to load off of it.

The port firing back wouldn't have enough breathing space, if I made the bandpass I'd have one or both ports facing up. (depending on 4th or 6th)



Meh, horns in cars are cool, but not really that great in my opinion. I would do a ported or 4th/6th depending on t/s parameters. Ported is going to be the best option most of the time, just regardless.

---------- Post added at 04:18 PM ---------- Previous post was at 04:17 PM ----------

You don't have to give up ridiculous space and test and cut all those crazy angles and pay 50+ for a design like that.

My goal for this sub would be:
good response between 25-50hz
I enjoy bass most between 30-40hz (realistically I like the lows a lot too but due to roll off I like the loudness which tends to be a little higher)
So probably a peak near 37.5hz or between 35-40hz

Following are the ALL the T/S Parameters that came in the box with the XFL1522 that I got in the mail today.

Imp: 2x2ohms
Rdc: 0.8ohms
Levc: 1.247mH
Fo: 30.3Hz
Sd: 81.43 msqM (<-- Whatever units that is...?)
BL: 11.203 TM
QMS: 4.216
QES: 0.559
QTS: 0.494
n: 0.494% (judging by the symbol I assume this is efficiency)
SPL: 90.2 dB
VAS: 63.3 L
Cms: 67 uM/N
Mms: 394.5 g
VC: 3"
Magnet: 220oz
Xmax: 19mm
RMS Power: 1000W
MAX Power: 2000W
F. Range: <300

So would you recommend a 4th or 6th order bandpass box?
I know it would be a little bigger than a ported box but this way I can have both ports facing the roof so it's louder, ported both would be facing the driver which I know would reduce output. I also like bandpass because it makes it pretty much stealproof lol, getting the sub out of the box would be so difficult, specially when the box takes up the whole boot and weighs a fair amount.

Buck
05-21-2013, 12:34 PM
I would still run an XFL in a 6th order.

RSDXzec
05-23-2013, 01:26 AM
I would still run an XFL in a 6th order.

glad to see we agree

programs like winisd and bassbox pro tend to recommend sealed or bp 4th for some reason...
but I know the manufacturer recommends ported and my responses graphed for 6th order look amazing.

My current design is
rear chamber: 2.8cf @ 48hz
front chamber: 4cf @ 28hz
Each with I'm hoping near 16"^2 of port per cube
I haven't finished calculations yet to see how much I can actually fit but the response I get in winisd is great
The blue line is the XFL and the green line are my current 12"s, this is without even accounting for differences in port area, my 12"s only have about 9.8"^2 of port per cube lol.

http://i39.tinypic.com/317h36s.png

This will dominate the lows, it's great for me since I don't like bass over 60hz and 50hz+ isn't that great for me, once it starts getting down to 40 is where it gets good imo

edit, just going over specs now I had around 9cf external to play with but after wood and ports etc looks like i only have around 5cf to play with (net internal volume taking out wood thickness, wooden wall in the middle and port displacement) so I'll have to see how i do this lol (this is if I used 16cf of port per cube...)

I'm considering going down to 14 if I can get away with it which seems to give me 5.5cf
12 per cube gives me 5.9cf to play with
how much port area can i sacrifice here?

Cheers.

Buck
05-23-2013, 11:10 AM
I would go up to 4 cubes rear as well. 4 cubes and 4+ cubes up to 7 or 8 if you wanted, depending on goals.

RSDXzec
05-23-2013, 11:44 AM
I would go up to 4 cubes rear as well. 4 cubes and 4+ cubes up to 7 or 8 if you wanted, depending on goals.

But isn't one chamber supposed to be significantly larger than the other?
And currently I'm having to downsize... if you read the bottom of my last post I have serious space bottlenecks here

Buck
05-23-2013, 11:52 AM
But isn't one chamber supposed to be significantly larger than the other?
And currently I'm having to downsize... if you read the bottom of my last post I have serious space bottlenecks here

Well, I was talking about a series 6th, not a parallel. If you were talking about a parallel 6th, I can see what you are saying more or less. I would do a series 6th though.

RSDXzec
05-23-2013, 12:05 PM
Well, I was talking about a series 6th, not a parallel. If you were talking about a parallel 6th, I can see what you are saying more or less. I would do a series 6th though.

oh ok, I'll see what kind of a response I get with a series 6th, I'll have to do it in bassbox pro since winisd doesn't model that.
Would a series 6th bp help with my space bottlenecks?
And wouldn't it technically reduce output since there's less surface area coming out?

Cheers.

Buck
05-23-2013, 12:17 PM
oh ok, I'll see what kind of a response I get with a series 6th, I'll have to do it in bassbox pro since winisd doesn't model that.
Would a series 6th bp help with my space bottlenecks?
And wouldn't it technically reduce output since there's less surface area coming out?

Cheers.

What do you mean here?

No, your output won't be affected as far as overall output. With a series 6th, your front chamber port needs to be about the SD of the woofer. So you will still have air movement man.

RSDXzec
05-24-2013, 12:13 AM
What do you mean here?

No, your output won't be affected as far as overall output. With a series 6th, your front chamber port needs to be about the SD of the woofer. So you will still have air movement man.

what I meant was does a series 6th order use less volume than a parallel 6th, apparently it seems to and with a larger bandwidth according to bassboxpro
For port area should I just make it so both ports wind speed is 20-25m/s at 1500watts? (I'll probably only use around 1k anyway) I still haven't worked out port areas and I'll be getting onto that soon

edit:
alright after a fair amount of work/calculations I have a 6th order series design let me know what you think
This will be built with 17mm structural birch plywood

http://i42.tinypic.com/dmpsnd.png

Box specs

Front Chamber
1.642cf @ 33.32hz
29.39"^2 of port area
29.39/1.642cf = 17.9"^2/cf of port area

Rear
3.735 @ 46.6hz
83.27^2 of port area
83.27/(1.642+3.735) = 15.486"/cf of port area

My port area seems pretty huge specially for the 1.64cf chamber, should I decrease these a bit and get more volume out of it?

Problem is with bassbox pro 6 it tells me I get peak port velocities of"
front (1.642cf):
18m/s @ ~ 24hz
rear (3.735cf):
10m/s @ ~ 41hz
This is when pushing a 1000watt signal through it.
I think it's good to keep port velocity under 18m/s I think so a smaller port on the smaller chamber seems like it would be pushing it even though it has a huge port area per cubic foot. What's your opinion?

Here's some BBP6 response curves
White line is the standard ported box
Red line is the BP6th Series box
http://i40.tinypic.com/2zyl7c6.png

Cheers.

Buck
05-24-2013, 09:52 PM
Man, that may graph up well, but I don't think it's going to sound that well. You have front and rear chambers backwards from what I can see.

You should try to get the rear and front about an octave or so apart (rule of thumb). Your rear chamber is way too small as well. 6th orders in general are not known for saving space. I think you may be applying the rules of a parallel 6th to a series.

RSDXzec
05-25-2013, 03:00 AM
Man, that may graph up well, but I don't think it's going to sound that well. You have front and rear chambers backwards from what I can see.

You should try to get the rear and front about an octave or so apart (rule of thumb). Your rear chamber is way too small as well. 6th orders in general are not known for saving space. I think you may be applying the rules of a parallel 6th to a series.

are you saying the low tuned port should be facing the outside world and the higher tuned port inside?
otherwise whats front and back is subjective... the motor of the sub will be in the large chamber because as you can see it wouldn't fit in the smaller one.
I figured having the higher tuned port facing out would be better because it allows me to have more external port area

Are you saying a good tune would be like 30hz and 60hz? possibly a little more/less? Not sure what's acceptable here.

I haven't gone off many rules other than how the response looks when I model it in bassboxpro

trying out the tuning and size recommendations I get this response, problem is it seems the 30hz-50hz region lacks a bit, which is the region i care most about. Although i don't know how the car envorinment would change this response.

http://i40.tinypic.com/fux8xy.png

white is the first design, red is the current box with recommendations

RSDXzec
05-27-2013, 12:10 PM
anybody got any feedback on the response graphs seen in my last post? Would that really sound better than my first design in a car environment?

edit: I think i may need a new thread for this topic since my design has changed so much it's nothing like the description in the first post.

Buck
05-27-2013, 12:16 PM
When you drop an enclosure into a vehicle, it boosts the gain tremendously. You can't rely on those graphs at all technically or literally, but only metaphorically in a comparison. A lot of time the t/s parameters with the woofer just don't match up well with the program so you can only use some of the info. A lot of time the 0 db line makes it look terrible because you cross it at something stupid like 40 hz which doesn't seem right, because it's usually not. The graphs are skewed in certain ways, you have to be able to recognize it and deal with it accordingly.

RSDXzec
05-28-2013, 12:35 AM
When you drop an enclosure into a vehicle, it boosts the gain tremendously. You can't rely on those graphs at all technically or literally, but only metaphorically in a comparison. A lot of time the t/s parameters with the woofer just don't match up well with the program so you can only use some of the info. A lot of time the 0 db line makes it look terrible because you cross it at something stupid like 40 hz which doesn't seem right, because it's usually not. The graphs are skewed in certain ways, you have to be able to recognize it and deal with it accordingly.

Well I clearly lack the experience to realise where/how the graphs are skewed, any tips/ways to realise this?
Would adding the cabin gain in bassbox pro help at all by using the resonant frequency of the car? I know to find it you need to measure the size of the cabin but I've never been sure if it's extreme corner to corner or from the centre of the dash touching the wind shield to the rear centre of the boot.

Another way I've heard of doing it is getting a sealed box and testing with a metre at all desired frequencies then estimating the gain curve compared to what winisd/bbp estimates.