DIY Speakers - JM Labs - Help!


Novice Member
Well i am about 90% certain i want to build another pair of DIY speakers and before I do I wanted to run them past a few people on here that maybe able to help with what I am thinking of doing.

I am thinking of building a three way system that is similar to the following JM Labs high end units:

Alto Utopia Be


Diva Utopia Be

So far I have decided (around 90% certani) on the tweeter and midrange units and so the drive units I have in mind are as follows:

JM Labs - TC120 TD5

JM Labs - Audiom 6 WM / 6W4411

Not really decided on this yet but a choice of either two of these:

a) JM Labs - 11K7512


b) JM Labs - 10W6411

I have the following questions for anyone on here that can help.....

1) Does anyone have the exact cross over circuit diagrams used in the "Alto Utopia Be" or the "Alto Utopia Be" JM Labs speakers??

2) Does anyone here own or heard the above two woofer units that can comment ?

3) Can anyone recommend or send me any free speaker design software (email address below) that will allow me to model the cross cover with the specs from the above driver units??

4) Box design. Currently I am thinking about having one totally sealed box split in two (one for the woofer and the other for the midrange / tweeter). Is this best ??

Thanks to anyone that can help!!

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Looks like an interesting proposal.

I'll try to answer your questions:

1. The crossover designs for the Alto/Diva Utopia Be would be next to useless to you since you are using completely different drive units, albeit from the same manufacturer. The Utopia Be designs use the berelium(spell?) dome for the treble and this is a very expensive model. Same goes for the mid-range and bass drivers.

What you need to do is start from scratch with the crossover or change the drive units but it would cost a small fortune to get hold of the speakers used in the Utopia Be range.

2. Never heard either - sorry

4. Its a good idea to physically separate the mid to high frequencies from the low stuff. Most higher end designs use this approach as less colouration is evident. So I'd say go with that.

Also since the design you are proposing is large its best to brace both cabinets heavily, especially the bass sections. This will help minimise resonances and again provide less colouration.


Ditto, use a kit from Zalytron, Madisound, or any of the other DIY speaker retailers. Check out Madisound on the "New Towers" posted by my son, Substrate.
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