# Turning an MTX 9500 12" into a 10"



## StockA4 (Aug 26, 2011)

This question is probably better suited to an SPL forum, but I'll give it a go here.

I have a blown MTX 9500 12" (as good of a place to start as any). I've already removed the soft parts and basket and would like to turn this into a 10" sub. The motor takes a 4" voice coil, so I figured after I located a basket I could drop in a recone (like for a Rockford Fosgate Power HX2). My question is; does anybody know offhand what basket I could throw on there? 

The distance between the middle of each diametrically opposed mounting hole is 6.5" (see pics).
















If more pictures or specs are needed, I'll be happy to provide.
Please bear in mind also that this is not meant to be anything but a toy. I'm not going to compete with it. I just want to make a beastly little 10" sub. Any help or direction I can get on this endeavor would be appreciated greatly.


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## indytrucks (Apr 5, 2009)

All 4" coils are not created equal. If contact someone like PSi or any other reputable speaker rebuilder before you do anything. You'll need to know your gap so they can make sure you can get the proper coil. Not to mention making sure you have the proper spider packs for what you intend to use it for.


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## StockA4 (Aug 26, 2011)

Thanks, Indy. I didn't know all coils weren't created equal. I forgot to state in my original post that I have no idea what I'm doing here, but I'd like to. I'm mostly an old schooler, so I've never had any use for a Frankenwoofer until now.


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## hurrication (Dec 19, 2011)

Post this on CACO and you will get answers from people who have done it.


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## StockA4 (Aug 26, 2011)

hurrication said:


> Post this on CACO and you will get answers from people who have done it.


Agreed. Thank you.


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## jp88 (Jun 25, 2007)

If you end up doing this please post information about it here. I for one am certainly interested in your results even though Im not into spl


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## StockA4 (Aug 26, 2011)

jp88 said:


> If you end up doing this please post information about it here. I for one am certainly interested in your results even though Im not into spl


It's probably going to be awhile because I have a few other projects taking precedence. But when I do get everything figured out, I will post everything here.


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## shawnk (Jan 11, 2010)

Just as a precautionary, 4 inch coils are not necessarily the best choice for 10" drivers due to limited excursion. You will not even come close to using that motor's full potential due to the suspension's limits in such a small driver. If this is a custom project just for fun, I'd suggest at least a 12" frame. Something like the TC "Ti" frames would be geat due to their 10" spider landings. I doubt any of the common frames will simply bolt right up, but you can have a good machine shop drill & tap new threads. Just make sure they know not to drill any deeper than the thickness of the top plate

Here's an example of the frame I'm referring to: 12" TC Sounds TI Basket Frame Subwoofer Recone | eBay

good luck!!


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## StockA4 (Aug 26, 2011)

shawnk said:


> Just as a precautionary, 4 inch coils are not necessarily the best choice for 10" drivers due to limited excursion. You will not even come close to using that motor's full potential due to the suspension's limits in such a small driver. If this is a custom project just for fun, I'd suggest at least a 12" frame. Something like the TC "Ti" frames would be geat due to their 10" spider landings. I doubt any of the common frames will simply bolt right up, but you can have a good machine shop drill & tap new threads. Just make sure they know not to drill any deeper than the thickness of the top plate
> 
> Here's an example of the frame I'm referring to: 12" TC Sounds TI Basket Frame Subwoofer Recone | eBay
> 
> good luck!!



Shawn, your suggestions are gold for me. Now, once I got a basket I was considering something like the Power HX2 10" drop in (or something like that). But while this is still a toy, I'd still like to get close to the motor's full potential. So now my question is; are you saying this particular motor is too much for a project like this? And if the answer is yes, it makes sense because I recently noticed the MTX 9500 10" and 12" had different sized motors. 

I still have the original basket for this motor (tall as it may be). I could just put it back together the way it's supposed to be. I was hoping this would be a simple swap and bolt and that finding the correct parts would be the hard part. Not that I'm shying away from any work. I just don't know what I'm doing, so the easier the better.


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## shawnk (Jan 11, 2010)

StockA4 said:


> So now my question is; are you saying this particular motor is too much for a project like this?


Sort of, yes. building speakers is all about compromises. So much so that I could sit here for the next several hours listing them all.... which I really don't want to do, lol.  

So yes, this particular motor "can" be custom fitted to a 10" top assembly and it "can" work, but just because it "can" be done doesn't necessarily mean that it's the most viable option. This motor uses a 4" coil (I believe anyway so please correct me if I'm wrong) which means that the spider's surface area is going to be minimized an you could actually see "less" excursion than a comparable motor using a 3" coil. I hope that makes sense. If not I'll try to describe a little more in depth.

Furthermore, and this will probably be the killer for you, you won't find any "drop in" soft parts for that motor. It will have to be a custom system. As previously mentioned, "not all voice coils are created equal" and basically that is true. You have to consider how everything is going to work as a package such as: the motor's gap dimensions , voice coil windings/height & thickness, depth of the cone, frame depth & spider landing provisions, length of the pole piece, desired excursion, desired power handling and efficiency, and even more which escapes me at the moment since I'm devouring some freshly baked brownies 

I'm not trying to discourage you, just offering some insight  I'll help as much as possible if you want to continue!


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## StockA4 (Aug 26, 2011)

The difference between the 3 and 4 inch coil vs. excursion makes sense. I hadn't thought of that before, although it's a key component in me getting what I want from my speaker.

I have a cookbook I should probably read first so that I have a better grasp on the mechanics of a subwoofer before I attempt such undertakings.

So thanks for your help, Shawn, Cajunner, etc. But I think I'll return to this once I've done a sufficient amount of reading.


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## shawnk (Jan 11, 2010)

Yes, the "Cookbook" should help!!


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## StockA4 (Aug 26, 2011)

shawnk said:


> Yes, the "Cookbook" should help!!


5th edition. I'm sure it's got plenty of info in it.

Thanks, Shawn.


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## cerwinvega_fan (Nov 9, 2010)

Wouldn't recommend turning that into a 10 since the motor has a 4inch coil.


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## StockA4 (Aug 26, 2011)

cerwinvega_fan said:


> Wouldn't recommend turning that into a 10 since the motor has a 4inch coil.


I've been hearing that. But then, my RF Power HX2 10 has a 4" coil, right? I haven't yet had the chance to put any real time or thought into this project.


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