[PMAT]

I have these bass drivers that I purchased on CL that are beautifully built and massive. I would like to try and build my own speakers in a 2-way or 3-way design for fun. I am good in the wood shop but new at speaker design. The drivers are built by Meyer Sound which manufactures Pro audio and Concert Venue systems. Their website doesn't contain info on older drivers and contacting them didn't work. The drivers are 8 ohm 12" Bass units with a pleated surround, heavy stamped steel frame, well ventilated cone and a big vented pole piece in a humongous motor. The cone it treated paper. V-max seems about 8-10 mm from at it looking while pushing the cone with my hand. I would like to use these drivers in a speaker for a man cave or even outside when I am gardening. Does anyone have experience using pro audio drivers or similar? What would you do for a design? Here are some pics. Thanks.

[S Clark]

Unless you can get someone to measure the Theil-Small parameters for that speaker, you have a very poor chance of making a reasonable 2 way system, and nearly no chance of making a decent 3 way system.  Perhaps your best bet would be to send them to some of us that can take measurements, use the specs to make a pair of sub woofers to go with a good set of DIY bookshelf speakers (using designs that have already been proven). Of course, for the cost of shipping them both ways, you can probably get a good pair of woofers that have already been measured- perhaps Danny Richie still has some the woofers that he had on sale.
http://www.audiocircle.com/index.php?topic=87767.0
Designing speakers is not exactly an easy undertaking, but it is a lot of fun.  Best of luck with your project.

Scott

[richidoo]

PMAT, looks like a cool driver. It looks like relatively high sensitivity.

Like Sclark said, it would be nice to know the technical specs of the driver to aid with designing an enclosure for it. If you know the part number you can find the published specs, or request them from Meyer. The stickers don't clearly show a part number that I can see. If you think you might want to tinker with other speaker projects in the future, you could purchase a Woofer Tester 3 for $100 from Parts express to measure the exact specs for this driver. If this is a one time thing, it's not worth it.

If you can't get the specs, it will be impossible to make a crossover to mate it with other drivers like mid or tweeter. Since you mentioned that you are only looking to make a sub or gardening speaker, you might be able to get by without the specs.

It will work fine for a gardening speaker because pro audio 12" drivers are usually intended as midrange drivers for guitar/bass amps or PA stacks and have relatively low inductance coils to allow playing well up into the upper midrange freqs, which for gardening is enough to understand voices and hear all the melodies. Forget about crystalline highs, but for outside work it will probably do. Put it in a sealed box about 2x2x2' and fill the inside halfway with pink insulation glued to all inside walls, but away from the driver. Point it toward your work area to get the most treble possible. Put some bracing inside the box to prevent wall flexing from pressure to make it sound cleaner.

Don't know if you mean by mancave speaker a full range party speaker or a subwoofer. If the former, the garden speaker should work fine, but don't expect crackling edgy dance beats without a high frequency driver. If it's for a sub woofer, there are a lot more issues to cover, and the driver is probably not ideal for that, but would be better than no bass at all.

[PMAT]

Thanks guys, I am sure that I want a fullish range speaker. I don't need anything above 16 khz or below 42 hz. I would like a two way with a fairly simple crossover. I will find out what the specs are for these drivers. My local Hi-fi dealer owes me a favor so maybe I can get them to measure the drivers. I love the robust nature of these things for some reason. The Meyers Sound site is interesting for me. http://www.meyersound.com/ They remind me of the JBL Hi-Fi speakers I used to install in the early eighties. By the way, gardening speakers are the rage in some parts of the world  But seriously, the outdoor sound can be addicting. No room interaction is so very different. The bass has no reinforcement and the imaging is so cool if you are at the right bush. I have three subs so I don't need another. I really want a ballsy speaker from this project. I know that this is backwards design but what the heck, I will learn a lot.

[Vapor Audio]

Without knowing anything about those drivers other than the pictures, I'd bet you'd be surprised with how little balls they have.  They're probably around 3mm of xmax and a resonant frequency in the 50-70hz range.  Again just an educated guess, but you probably won't get any more than 50hz -3db extension from them.   Of course you could use them in a project, but just have reasonable expectations.  High sensitivity and bass extension are an either/or proposition.  To get high sensitivity you need low moving mass, to get bass extension you need more moving mass ... so looking at the cone and cloth surround, I'm assuming these are aimed at high sensitivity at with the trade-off of little bass extension.

You'll need more than just T/S parameters, you'll also need frequency response data if you're planning to use it in a 3-way build. 

I know you'd like to use them, but unless you're setup to collect the required data, your best bet would be to use other drivers for which the necessary data is already available. 

[PMAT]

Assuming that you're right what would these drivers be good for? A great PA or a guitar speaker? Fog horn? 

[JohnR]

You could put them in an open baffle and stick an alpha 15a underneath them with an active crossover and then look for a tweeter after measuring the result.

[Vapor Audio]

Assuming that you're right what would these drivers be good for? A great PA or a guitar speaker? Fog horn? 

I don't mean to say they're useless, just to have proper expectations.  You say you want something with balls, these may not be what you're looking for.  Then again, I could be wrong ... the only way to know is to collect the necessary data.  If you're anywhere near St Louis I'd be happy to measure them for you.  You could also write Meyer and see if they have data on that driver they could provide.

[richidoo]

It won't have bass impact balls like a ported sub, but it will have tonal balls in the lower mids.

Most 12" pro drivers have a cone break up peak at 4-5kHz before rolling off quickly above that. That is high enough to hear vocal sibilants and the natural edge in music, especially if the voice coil inductance is relatively low. You don't need 16kHz for your application, imo. But the treble will beam very strongly, so you have to try it and see what works in your listening "space." It might be too focused, and a tweeter will have much more dispersion so you can hear the high freqs across a wider area.

You can test whether the drivers' treble is sufficient without a tweeter by playing music in it while pointed to where you will be listening to concentrate the beaming highs towards you. You don't even need a box for this, since that mostly affects the bass freqs.

The nice thing about a sealed box (besides being very easy to design) is that it rolls off slowly, making the bass sound full, even if it's not punchy like a reflex port can be. But that's more important for serious listening.

[PMAT]

I hooked one up in my main system and the mids were there but muffled for sure. I also played my HSU Bass tester cd. It had steady low output and was still moving at 20hz. This might be a bass unit. I will get it tested somewhere. Possibly I could make a good outdoor party speaker. What do you think of pots for leveling a tweeter or a mid-tweeter? Also, the huge vent on the back of the magnet in picture 3 is one inch across. Do pro mids have these?

[roymail]

http://audiokarma.org/forums/showthread.php?t=150939

PMAT, I suggest you spend some time with the above thread since the Ewaves are 2-way, use pro woofers in many designs, crossovers are  easy to make, results are highly rated.

Your speakers do appear to be pro style woofers, therefore probably have good sensitivity.

[PMAT]

Thanks for the link! Interesting stuff the e waves. May be just the ticket. I cant bear to chuck these drivers. To hold one is to love it. The magnet is 7 inches across! I would like a FAT sound when I am done. Big woofs and tube power perhaps. Any help is very much appreciated. My local Stereo shop says they have the measuring equipment to give me the specs. I will post back after that. After modding my VMPS with peerless woofers I am hooked.

[roymail]

After modding my VMPS with peerless woofers I am hooked.

Those are some very nice speakers.  Since you have those, a pair of 2-way horns might just be a good alternative.

[richidoo]

After modding my VMPS with peerless woofers I am hooked.

Uh-oh! You didn't mention the addiction before. That changes everything. Definitely build the three way.