Winter project ?

[Adder]

Hello folks,

I joined up back in May looking for a little advice with a project that i was thinking about. Well now the nights are drawing in its time for me to hopefully get busy with my jigsaw and soldering iron. I have been trying to post a few pictures but for some reason it would only let me preview them and not post them up ? Anyhow, i got a pair of Mordant and Short MS20s and a pair of Mordant and Short Pageant 2s. High end audiophile they are not however, they all work and sound fine.

What im interested in is putting both drivers wired in paralell with any one of the original tweeters and again any one of the crossovers into one cabinet. Which leads to my next issue which is although the main drivers are the same size the Pageants are in a bigger, ported cabinet where as the MS20s are in a smaller sealed cabinet. Would i be correct in thinking just add the volume of both boxes together ?

Finally i have a pair of 12" sub drivers left over from my car audio days again, doing nothing. Now these are 4 ohms, could anyone recommend a crossover that would cut of at say 30 to 40hz please ?

I would class my self as a novice electronicaly so please be gental with me ! Thank you in advance for
any help or advice,

Adder

 

[Tenson]

Hello Adder,

If the speakers work, you are best to use the one you like most and sell the other on eBay or something. Putting both bass drivers together will really mess up the design work done by MS.

The crossover electronics are specifically designed to work with the woofer and tweeter in each speaker, so you can not use a different woofer or put an extra woofer on the output of the crossover and expect to get any sort of sensible result.

If you did add both woofers to a box of ~twice the volume you will need to change the port length and size because this is dependant on the box size and amount of air being moved by the woofers. You will get more output than having one woofer which will then make the tweeter seem too quiet. You will also get a very strange sound around the crossover points of the woofers / tweeter due to the problem mentioned n the above paragraph.

If you want a fun project and don't want to buy any new parts (there are DIY speaker kits) I might recommend choosing the speaker you like most and making a new slightly bigger cabinet with more bracing and damping. As a rough guide if you made a box with 1.5x the volume you should probably reduce the port length by about 30% keeping area of the port the same.

 

[Adder]

Hello thankyou for your reply,

I thought it wasn't going to as straight forward as I thought, both the drivers are identical so I think I will do as you suggest and just make the MS20s into are slightly larger box. I think even just copy the diamentions of the Pageants. Just one last thing , in your opinion would I be right in thinking a 120hz crossover will be ok for a deep bass ? I know a it's a little vague I'm just trying to get an idea of what I'm doing.

Regards

Adder

 

[Jimbo]

Hello thankyou for your reply,

I thought it wasn't going to as straight forward as I thought, both the drivers are identical so I think I will do as you suggest and just make the MS20s into are slightly larger box. I think even just copy the diamentions of the Pageants. Just one last thing , in your opinion would I be right in thinking a 120hz crossover will be ok for a deep bass ? I know a it's a little vague I'm just trying to get an idea of what I'm doing.

Regards

Adder

It isn't straight forward. There are quite a few things you need to find out first and that is the speakers Q parameters and Vas. Port opening and length too. The best thing to do is try diyaudio forums as there are some knowledgeable diy-ers on there. You may even get to use your twin speakers as a isobaric design.

 

[Tenson]

I'm not sure what you mean about a 120Hz deep bass crossover. You mean to the 12" woofer you have? 120Hz would be okay if you run the subs in stereo but you still need to get the phase right between the main speaker and the subs and placement relative to each other will affect that. That's why when I made the Advantage 'subs' to go with the Kensai mini monitors I designed them to sit under the speakers as a stand so that way I know exactly where they are relative to each other, rather than make a sub that can be placed anywhere and the sound could do anything too.

 

[Adder]

Hello,

Yes I have a pair of 12" woofers, I've done a bit of searching and managed to get hold of the TS parameters so hopefully i will be able to put something together


Adder

 

[Tenson]

Are you going to use an active crossover? I'd advise active or digital. Passive will be really tricky to get right.

 

[Jimbo]

As tenson said you have to get everything right or you will end up with wasting time and money and something that sounds awful.