3 way MTMB

[CCU]

Hi i'm thinking about making a pair of new speakers and i was wondering if the units that i've looked at would be a good fit for each other.

tweeter: Vifa XT25BG60-04
Link

Bass: Peerless XXLS 830847
Link

Midrange: Peerless HDS 830875
Link

i also considered the little brother of the midrange unit, but discarded the idea because of lower effiency

I were thinking of making the crossover point at 300/2500hz

does anyone know a reason why this would't work well together?

Best regards

 

[infinia]

Hi
Very good driver choices for your crossover targets.

1) The vifa tweeter should be better at the 8 ohm version instead?
2) Woofer is a DVC in parallel at 3 ohm, s/b easier to implement BSC designs. Should be fine using high current amplifiers. If you are using bass reflex the port will be around 45 cm long.
http://www.tymphany.com/830847-app-note

3) Excellent 8 ohm midrange. Easier to cross at 2,5K than the phase plugged version. Not as good at LF distortion, but less an issue here if crossed at 300Hz.

edit> oops just realized you have 2 mids for MTM, so use 4 ohm all around then. Now a MTM wants at least a 3rd order response at a freq probably lower than your than your target. Xover to the tweeter at a freq. related to the spacing of the mids.

 

[Andy G]

a 12" xxls used to 300Hz ???

 

[crazyhub]

a 12" xxls used to 300Hz ???

Piston range up to 450Hz so why not?

 

[Moondog55]

i would have used a sealed box and this woofer
http://www.tymphany.com/830669
if it was Me/ but I have no personal experience with these particular drivers, I just looked at the break-up peaks and dips and thought that 120Hz tops for the XXLS



A pair of these would however need a bigger box than 1 X ported

 

[Andy G]

there is way more to it than piston range.. the main issue is what it will sound like !!

If he thinks he can make an XXLS sound decent up to 300Hz.....OK. 😎

Its just not something I would attempt.

 

[crazyhub]

there is way more to it than piston range..

Way more what? Please say us the technical reasons you think so, thank you.

 

[infinia]

Re: Re: 3 way MTMB

oops just realized you have 2 mids for MTM, so use 4 ohm all around then. Now a MTM wants at least a 3rd order response at a freq probably lower than your than your target. Xover to the tweeter at a freq. related to the spacing of the mids.

I think 3rd order filters at 1.8~2.0KHz with closest spacing between mids would be advised. Then your tweeter might not like that tho

see D'Appolito MTM http://www.parts-express.com/projectshowcase/indexn.cfm?project=USHERs


search http://www.google.com/search?hl=en&q=D'Appolito++MTM++crossover&btnG=Google+Search&aq=f&oq=

 

[CCU]

there is way more to it than piston range.. the main issue is what it will sound like !!

If he thinks he can make an XXLS sound decent up to 300Hz.....OK. 😎

Its just not something I would attempt.

well the crossover point could go down to 100hz, the midrange drivers could easily go that far down, but then i might have to make that box a basreflex also

 

[CCU]

i would have used a sealed box and this woofer
http://www.tymphany.com/830669
if it was Me/ but I have no personal experience with these particular drivers, I just looked at the break-up peaks and dips and thought that 120Hz tops for the XXLS



A pair of these would however need a bigger box than 1 X ported

that would make the box to big

 

[CCU]

Re: Re: 3 way MTMB

Hi

2) Woofer is a DVC in parallel at 3 ohm, s/b easier to implement BSC designs. Should be fine using high current amplifiers. If you are using bass reflex the port will be around 45 cm long.
http://www.tymphany.com/830847-app-note

edit> oops just realized you have 2 mids for MTM, so use 4 ohm all around then. Now a MTM wants at least a 3rd order response at a freq probably lower than your than your target. Xover to the tweeter at a freq. related to the spacing of the mids.

The speakers impedance will approximately be 3-4ohm and my should not have any problem with that.

the spacing and placement between the drivers is more or less going to be a trial and error process

 

[Andy G]

well the crossover point could go down to 100hz, the midrange drivers could easily go that far down, but then i might have to make that box a basreflex also

As Moondog says, 120Hz tops for those Peerless xls drivers. This is normally where thay are crossed (eg The Orion.. look at the effort that SL made to push the x-o point down to 120).
You will not find anyone who knows what they are doing, crossing them much above 120. Its to do with the distorion characteristics etc.

 

[tinitus]

The thing is that many people think that a 300hz xo point is the end of it, but reality is that it is just as important what it does past the 300hz

 

[crazyhub]

As Moondog says, 120Hz tops for those Peerless xls drivers. This is normally where thay are crossed (eg The Orion.. look at the effort that SL made to push the x-o point down to 120).
You will not find anyone who knows what they are doing, crossing them much above 120. Its to do with the distorion characteristics etc.

Do you have some links about why SL pushed the x-o point down to 120Hz? And or a link about distortions of this XXLS?
At the moment I don't see any technical reason, I really wish I would.
Sure, as tinitus pointed it out, 300Hz with a low order filter will very certainly let one hear the flaws of this driver but nothing else about to my mind 🙂

 

[Andy G]

sorry no links, and I don't have the tech stuff in my memory any more.

From my experience, most these long throw SUB drivers just don't do the upper bass well at all. They get sort of wooly and imprecise sounding. I think its probably to do with intermodulation distortion from the high excursions they have at lower frequencies, and the fact that you are trying to make a heavyish cone do frequencies it really doesn't want to do.

 

[tinitus]

Very big stiff and heavy cone surround may play an important role here and maybe also the spider, but probably NOT the cone weight itself

 

[crazyhub]

and high VC inductance inducing a restricted high-bass spl vs low-bass but with the help of the two mid-bass...

 

[tinitus]

120hz or 300hz may not mean a whole lot of difference as there is a risk of muffled midrange in BOTH cases
Sub drivers are intended to be crossed around 50hz, and as all this is purely theoretical we really need to keep to the known basic rules to "play safe".
But its still speculations and doesnt mean it wont work in any case
Theoretically I would look fore lowest possible Fs with lowest possible cone weight, whatever that is

 

[CCU]

thanks so much for the answers, but if any of you had to recommed a woofer, what would that be?

 

[tinitus]

Ups, tough one 🙂

Lets see
I suppose you want the low Fs, which makes perfectly sense
And you want to squeeze a bit exstra out of it, which also makes sense, if possible
Well, Fs around 20hz is pretty good with mms of 100gr

So to stay close to your own choice there are a couple of other drivers that looks a bit better
But its hard to guarantee anything...many things could depend on your skills to make the xo design and proper adjustments

http://www.tymphany.com/835016

http://www.tymphany.com/835017

But they are listed as OEM so I dont know if they are available at all

Like another one mentioned, you may consider to use only one mid...and maybe the smaller 5" could be a better choice, but it may depend on what you are trying to achieve...the 6" may be better at loud SPL, and the 5" better fore the finer things

Mind you, this is based solely on common sense, reality could be different