Speakerplans.com Homepage
Forum Home Forum Home > Plans > X10, X12, X15 and XM15
  New Posts New Posts RSS Feed - xm 15?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

xm 15?

 Post Reply Post Reply
Author
Message
Tumble View Drop Down
Registered User
Registered User


Joined: 09 July 2004
Location: SouthWest UK
Status: Offline
Points: 353
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tumble Quote  Post ReplyReply Direct Link To This Post Topic: xm 15?
    Posted: 01 August 2005 at 2:53pm

i know the design is ment for p audio drivers and those special crossovers. i hav a spare eminence kappa 15(cast frame) and a pxb2-1k6 crossover, could i use them rather than the p audio. also what compression horn should i use?

cheers

t

Retox
Back to Top
ceharden View Drop Down
The 10,000 Points Club
The 10,000 Points Club
Avatar

Joined: 05 June 2005
Location: Southampton
Status: Offline
Points: 11625
Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 03 August 2005 at 7:00am
If you used the Kappa15 with a PSD2002 (eminince 1" comp driver) and the 1k6 crossover you'd get a fairly useable box, but it wouldn't quite be an XM15 as intended any more and probably wouldn't sound as good as the P-Audio drivers.  You might need to check the tuning of the cabinet for the kappa 15 (plug it into WinISD or similar and try it).
Back to Top
Timebomb View Drop Down
Old Croc
Old Croc
Avatar

Joined: 11 October 2004
Location: Lancaster
Status: Offline
Points: 2691
Post Options Post Options   Thanks (0) Thanks(0)   Quote Timebomb Quote  Post ReplyReply Direct Link To This Post Posted: 03 August 2005 at 7:23pm
Be carefull with the low xmax on the kappa 15 (if its the non LF version)  im building come closed boxs and some ported boxs tunes quite high to restrict the excursion with the 4 kappa 15s ive got,  they really need somthing elce covering most of the bass though as they dont sound nice past xmax.
Back to Top
Tumble View Drop Down
Registered User
Registered User


Joined: 09 July 2004
Location: SouthWest UK
Status: Offline
Points: 353
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tumble Quote  Post ReplyReply Direct Link To This Post Posted: 04 August 2005 at 10:21am

wicked cheers guys. .

@ceharden, can you elabourate on the tuneing bit (this is the first cab im building myself)


@Timebomb, by 'be careful with the xmax' do you mean dont push the driver too much, or?

thanks again

tom

Retox
Back to Top
Tumble View Drop Down
Registered User
Registered User


Joined: 09 July 2004
Location: SouthWest UK
Status: Offline
Points: 353
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tumble Quote  Post ReplyReply Direct Link To This Post Posted: 04 August 2005 at 10:56am

also, what horn would be best.

 

Retox
Back to Top
ceharden View Drop Down
The 10,000 Points Club
The 10,000 Points Club
Avatar

Joined: 05 June 2005
Location: Southampton
Status: Offline
Points: 11625
Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 04 August 2005 at 2:02pm
Re: Tuning

The volume and port size of the cabinet are 'tuned' to match or complement the loudspeaker driver.  If you're interested in the theory the cabinet is a resonant system directly equivelent to blowing across the top of a bottle only instead of your breath you have a loudspeaker instead.  The note you get is related to the volume of the cabinet/bottle and the size of the port/neck of the bottle.

Correctly tuned, the cabinet will smoothly extend the low frequency response of the loudspeaker driver, whereas incorrectly you'll get perhaps lots of bass at one frequency and very little elsewhere.

The maths to calculate this is quite involved so programs such as WinISD (google for it and read the help perhaps) simplify the process.  You input the parameters for the driver and the cabinet and it can tell you what the frequency response is likely to be.  Alternatively it can calculate the ports required for a certain response.

Re: Xmax

The Xmax specification for a driver can be loosely described as how far the coil can move in the magnet before it leaves the useful part of the magnetic field.  The displacement possible before damage is usually larger than this but you want to avoid running a driver past Xmax.  A driver with a low Xmax will reach its limit of how much low bass it can produce quicker than a high Xmax driver (low frequencies = more air movement required).

Re: Horns for compression drivers

I'm probably not the best person to answer this as I haven't listened to many different ones.  Have you chosen a compression driver and just need the horn, or do you need help with choosing both to match the kappa15's?

Hope this helps....
Back to Top
Timebomb View Drop Down
Old Croc
Old Croc
Avatar

Joined: 11 October 2004
Location: Lancaster
Status: Offline
Points: 2691
Post Options Post Options   Thanks (0) Thanks(0)   Quote Timebomb Quote  Post ReplyReply Direct Link To This Post Posted: 04 August 2005 at 7:59pm
I mean you may want to tune your cab high to stop the driver going behond xmax, it dosent sound to nice and your not going to get much low bass out of a kappa 15 anyway.  Really a small closed box is the way to go, and its the most straight foward to design.
Back to Top
Tumble View Drop Down
Registered User
Registered User


Joined: 09 July 2004
Location: SouthWest UK
Status: Offline
Points: 353
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tumble Quote  Post ReplyReply Direct Link To This Post Posted: 05 August 2005 at 3:49am

i was thinkin of the PSD2002 (eminince 1" comp driver), should i use an eminince flare or the p audio as in the design.

or would i be better off designing my own cabnet to match the specs of the drivers.

so with an x-max of 3.2mm and a resonant frequency of 47Hz, i should tune the box to about 50Hz, to the driver dosnt reach its limmits?

cheers for your help guys, learnin alot here.

tom

Retox
Back to Top
ceharden View Drop Down
The 10,000 Points Club
The 10,000 Points Club
Avatar

Joined: 05 June 2005
Location: Southampton
Status: Offline
Points: 11625
Post Options Post Options   Thanks (0) Thanks(0)   Quote ceharden Quote  Post ReplyReply Direct Link To This Post Posted: 05 August 2005 at 7:20am
The PSD2002 will be fine to match the Kappa15 with a 1k6 x-over.  You might need to put some attenuation in (L-pad) to reduce the level of the compression driver with relation to the 15".  If necessary this can be discussed later.  Choose a horn flare with a 1" throat which matches the design of your cabinet.  A medium sized 90x60 exponential horn will probably do the job.

You should probably try to learn your way round WinISD or another program, because once you have, designing sealed and ported cabinets becomes fairly easy.  I've had a quick play myself and found that the Kappa15 isn't really useable below about 80-100Hz so you'll most likely need to use the cabs with some subs.  Adjusting the tuning doesn't seem to give much improvement over that specified for the P-Audio drivers so you could just build the XM15 cabinets as is.

I do actually have a pair of SN15MB's new in their boxes bought for a job which fell through which I might be willing to part with.....
Back to Top
Timebomb View Drop Down
Old Croc
Old Croc
Avatar

Joined: 11 October 2004
Location: Lancaster
Status: Offline
Points: 2691
Post Options Post Options   Thanks (0) Thanks(0)   Quote Timebomb Quote  Post ReplyReply Direct Link To This Post Posted: 05 August 2005 at 9:49pm
I think the kappa 15 has an xmax of 1.6mm one way so a tuning of 50Hz is going to make it reach its xmax on very low power levels, high power levels will not sound nice.
Back to Top
Tumble View Drop Down
Registered User
Registered User


Joined: 09 July 2004
Location: SouthWest UK
Status: Offline
Points: 353
Post Options Post Options   Thanks (0) Thanks(0)   Quote Tumble Quote  Post ReplyReply Direct Link To This Post Posted: 07 August 2005 at 2:07pm

would love to buy your SN15MB's, but im skint! out of intrest, how much for the pair, got a mate who might want them.thought i build 1 cab as i ve got a spare driver lurkin. not realy worried about it going low as its only gunna b used as a dj montior.

thanks againfor all the info.

tom

Retox
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.125 seconds.