Help measuring drivers for a 2-way

[Ryan_Mc]

Hi everyone,

I'm sure this deserves it's own thread but since this a thread filled with people from Southern Ontario, it seems a bit appropriate...

I'll try to keep this short - I'm building a TM for a friend as sort of a house warming present. I'm using the 27TDFC and Peerless 830883. Typically I'd trace Zaph's measurements and model from there but I've since found widely different data for the Peerless drivers, apparently there must be a few different versions floating out there. Problem is that I'm just starting to learn to measure and I still need to send my mic out to be calibrated and I'm not sure I have enough time to get it all sorted out. So I'm wondering if anyone in the GTA (or close enough) can measure the drivers for me in the completed boxes. I have a WT3 so I have the ZMA files under control, I just need the FRD's.

If anyone can help me out let me know!

Thanks,
Ryan

[A Vanderkruk]

I can help if you are close to waterloo and bring them I'd like to look at them
Andrew

[mill23bay]

Nice of you to do a special build. Cool idea to warm up a house with what I can imagine would be a nice set of speakers. Keep us informed with your build(if you don't mind)
Peter C.

[anatech]

Hi Ryan,
A new thread might be in order.

Having said that, Andrew and a few others (John or example) can certainly give you a hand. One thing you should realize is that you don't need a mic in order to design and build the box. So get started already!

BTW, Peerless make great drivers. You can simply order them and measure their parameters on your own as well. Thiel and Small are your friends with this task. Some bench test equipment is what you need in order to figure this stuff out.

-Chris

[Ryan_Mc]

Originally Posted by mill23bay

Nice of you to do a special build. Cool idea to warm up a house with what I can imagine would be a nice set of speakers. Keep us informed with your build(if you don't mind)
Peter C.

Thanks, well it'll be nice if it all works out. He sort of has limited means right now just getting started and buying a new house on his own. He listens to me ramble about my speaker projects a lot and I know he's itching for a decent set of speakers. He's also a musician and he likes coming to my house to listen to my latest project or crossover tweak. I really hope he likes them. I can post up some pics if you'd like?

Originally Posted by anatech

Hi Ryan,
A new thread might be in order.

Having said that, Andrew and a few others (John or example) can certainly give you a hand. One thing you should realize is that you don't need a mic in order to design and build the box. So get started already!

BTW, Peerless make great drivers. You can simply order them and measure their parameters on your own as well. Thiel and Small are your friends with this task. Some bench test equipment is what you need in order to figure this stuff out.

-Chris

Thanks Chris. I've already used the WT3 to get the T/S parameters... which is what initially got me onto realizing there's different versions of this woofer out there. Though the T/S #'s are quite different I don't know if the FR has changed significantly. This woofer certainly looks like it means business and Zaphs measurements seems to back that up. The boxes are already halfway through construction. ~15L after subtracting for drivers, bracing, the port, etc. and will be tuned mid/low 40's IIRC with a 2" port if it matters here.

Originally Posted by A Vanderkruk

I can help if you are close to waterloo and bring them I'd like to look at them
Andrew

Thanks a ton! I've still got about 2 months till crunch time. Sounds like a lot but I work pretty much 7 days a week + family + my boss is taking a lot of holidays which puts me on-call 24/7 + it's fence building time as I'm in a new house + I still have to get all this figured out + I still need my mic calibrated + I work kind of slow. So I think that 2 months is going to go by pretty fast. I'm going to make an effort to do this myself but atleast I have a backup plan now. TBH I wasn't expecting an offer anywhere near that fast so I guess that gives you a whole lot of a heads up. I'll keep you informed how I'm making out and the likelihood I'll need your services. But thanks again!

[mill23bay]

Some shots of what you are doing would be great.
Peter C.

[anatech]

Hi Ryan,
Yep, I agree with Peter. Show us your progress as you go. If you need help attaching the pictures, help is here.

Things are a lot different from when I designed and built speaker enclosures! Back then you had to measure your own drivers for "real" specs, and only a few companies published them to begin with. I've even lost touch with the Peerless driver numbers, and those were my preferred drivers. The 8" drivers I used would run down to just below 30 Hz -3 dB, and the 10" drivers were closing in on 20 Hz, -3 dB in a B4 reflex. I have no doubt you'll be able to get right down there. The room is another story though ...

-Chris

[Ryan_Mc]

Ok, here's some pics of where I am now. One cab is well underway, the other is still in pieces.

It's a 0.5 ft³ box after all the extras are subtracted out that measures about 15" tall, 9" wide and 12" deep. The baffle is 1.25" (1/2" + 3/4") thick, the sides are laminated 1/8" hardboard on the inside and outside with a kerfed 1/2" middle held together with polyeurethane construction adhesive - I still need to trim them up obviously. The top, bottom and back will be 7/8", 3/4" and skinned with 1/8" to hide the edges of the laminated sides better. The bottom piece has the strips added to them to give me some extra meat as I will be putting threaded inserts in the bottom for feet/spikes or in this case to bolt them onto the stands. Plus it gives me something to screw the XO board to on the inside. Doing that limits me to an XO board about 8" x 5" so here's hoping it'll all fit... since I don't have an XO designed yet. Though I can access to top of the cab pretty well to so I can always put the tweeter XO up there and the woofer XO on the bottom if need be. You might notice the drivers are slightly proud of the baffle but that's to account for the thickness of the veneer. Oh and all of the joints of the 'frame' are biscuited. I'll take some more pics of the other box as I build it.

I'm in armpits deep now and can't change much at this point but I welcome any constructive criticism or any input for that matter, maybe something I can remember for my next build.

Thanks,
Ryan

[mill23bay]

That baffle board is nice, neat construction. I like the kerfs and the smooth bends. Looks good. Would you consider putting the xo on the outside of the cab. in it's own small box. Easy to play with later.

Peter C.

[giralfino]

Ryan,
nice construction - in fact I'm building a pair that looks pretty identical to your but using different techniques - I'm even using the same midwoofer but a different SEAS tweeter (27TBFC/G). I'm not ready yet to implement a xo but have done some simulations.
BTW, can you share the QC date of your 830883? mine are out of hands at the moment.
Ralf