# Need help tuning a tower



## BuddahX (Jan 6, 2010)

I'm designing a couple towers with 4 Woofers in them. I know these might not sound the best but want to try. I was thinking of using the Crossover's from the Definitive technology towers. and was curious on what hz should I tune the tower or do you have any suggestions. Im using (4)http://www.parts-express.com/pe/showdetl.cfm?Partnumber=299-935 and (1) http://www.parts-express.com/pe/showdetl.cfm?Partnumber=264-1014 in each tower. any help with design will help alot. First time trying. Thanks for the input.


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## StereoClarity (Apr 22, 2008)

Do you know what SD is on that woofer? It's not listed in the specs but you need that to model them. I'm looking but I can't find it.


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## StereoClarity (Apr 22, 2008)

My guess is that SD is somewhere close to 107^2cm. I tried using that value and those drivers model nothing short of terrible. Now, that SD guess of mine isn't exact but I'd bet it's close. A 5.25" driver would have an SD close to 98 and a 6.5 closer to 135 so I think 107 is pretty close.

I'd look into a different driver. I know those are cheap but it might not be worth it.


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## StereoClarity (Apr 22, 2008)

Maybe try something like this dayton driver. A little more but you'll certainly get results that are worth your effort.


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## 1Michael (Nov 2, 2006)

If you are going to change the drivers you will need to redesign the crossover.


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## BuddahX (Jan 6, 2010)

I jumped the gun on this. Didn't really think it through all the way. I already bought all the woofers. So not sure what to do lol. that sux.


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## 1Michael (Nov 2, 2006)

Well it does not look like you broke the bank on this venture...if you want to build some speakers why not build one that has already been designed like one from here?http://www.htguide.com/forum/forumdisplay.php4?f=39


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## JCD (Apr 20, 2006)

I plugged the info into WinISD and it spat out the following data:

Volume: 2453.2 in^2
Tuning: 58.6hz
Vent: 1 x 4" wide 3.94" long
Box -- Internal dimensions: 13.67" x 21.87" x 8.2" (WxHxD)

Looking at the published effective ranges for the two drivers, I'd probably cross them over ~2500hz
Also looks like you'll have to pad the woofers a little. The SPL is showing 93dB's for the 4 woofers. The tweeter is rated at 91.7dB's.

This modeled to a -3dB at 53.3hZ.

Now, the problem that's obvious is the dimensions that WinISD spat out for the interior of the box will not accommodate 4 x 5.5" woofers. Maybe something like 12" x 27.25" x 7.5" would work though. 

You may or may not need to include some sort of BSC.

That was the easy part. Determining what the crossover is supposed to be, that's the hard part. Unfortunately, you can't just pull the crossover from one speaker and put it in another. It will require some research (e.g., what type of crossover, what order of crossover, what crossover point, how much padding may be needed, will a BSC be necessary, should you include a notch filter, should you include a Zobel network, how to wire the woofers, what crossover parts to use). 

Another issue is the physical layout of the drivers. E.g., should the simply be lined up down the middle of the front baffle or should they be offset? Also, will you be rounding the corners? And if so, how much?

I know that someone said these don't model well, but I have no idea. But since you bought the drivers already, I just wanted to throw out some of the issues that are left over. There are plenty of online calculators for the crossover, but those work with "ideal" situations, which drivers never are. If you want to get something "right", it takes quite a bit of modeling, testing, measuring, repeating.

However, that's a significant investment I'm sure you're not excited to make. With that in mind, I'd probably just plug 4 ohms for the tweeter and 4 ohms for the woofer into some online calculator and see what pops up. Here is one online calculator for the crossover. And here is a calculator for the lpad.

Plugging in the values, I got:










Capacitors
C1 = 7.96 uF
C2 = 7.96 uF
Inductors
L1 = 0.51 mH
L2 = 0.51 mH
Resistors
R1 = 0.56 Ohms
R2 = 24.78 Ohms

Part Cost ~ $20/speaker

You could cut the cost by going with a first order crossover. It might work OK with these drivers since they have some decent (published) overlap.

Will this work? It will.. at least to some extent. Will it be any good? Probably not that good, but without having the tools and time and understanding, I think it's going to be difficult to do much else. Unless of course you can find someone who has built something with the drivers you choose.

I'm pretty sure you'll have to wire 1 pair of woofers in series and then the two of those in parallel to get a 4ohm ending load. I always get confused with that part.

Again, not ideal, and the results will be kind of a roll of the dice, but if you want to try, it might be the way to go.


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## BuddahX (Jan 6, 2010)

thanks for all your help man. Im still not sure what im going to do. But I think im going to take back the speakers. I have my eye on a full set of woofers tweeters and crossover from a Definitive technology's BP6 I might pick up and just build the tower the same as the original. That might be easier for me seeing that I am a newb and know nothing on how to wire up a crossover network and modeling and all that.


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## fbov (Aug 28, 2008)

Jumping in over one's head is common around here, and the perfectionist mentality of DIY audiophiles will sometimes mislead a newcomer. 

It's hard to make a speaker that doesn't work (although white vans will sell them to you), so don't give up yet. JCD has given you a significant opportunity to start learning about speakers - build this design and see how it sounds. An unfinished MDF box will suffice; don't make it look pretty until you know it sounds pretty good. It won't be impressive to a "golden ear" but it might be all you need for now. If not, you've got leg up on the next build. 

Now, if you're put off by the very thought of soldering up a crossover circuit, it's a different story. There are a number of kit vendors who will provide completed XO boards, but that gets into the very different question of your objectives, room size, loudness requirements, etc. To whet your whistle, browse some of the sites here:
http://techtalk.parts-express.com/showthread.php?t=211558

Finally, you are at the edge of a bottomless pit; if you fall in, your biggest problem will be finding homes for all the speakers you build...

HAve fun,
Frank


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## lsiberian (Mar 24, 2009)

The results look fine to me. You can put woofers on the back and front of the box to create an omnipolar like setup.


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## lsiberian (Mar 24, 2009)

fbov said:


> Jumping in over one's head is common around here, and the perfectionist mentality of DIY audiophiles will sometimes mislead a newcomer.
> 
> It's hard to make a speaker that doesn't work (although white vans will sell them to you), so don't give up yet. JCD has given you a significant opportunity to start learning about speakers - build this design and see how it sounds. An unfinished MDF box will suffice; don't make it look pretty until you know it sounds pretty good. It won't be impressive to a "golden ear" but it might be all you need for now. If not, you've got leg up on the next build.
> 
> ...


Just learn how to add on your own rooms to the house.:R


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## BuddahX (Jan 6, 2010)

LOL I live in an appartment. I'm going to try to get the part's from the Definitive BP6 towers. and build towers for those since its all there. the parts express speakers I'll probably use them for my rear stage and tinker around with them. I don't need them to sound EPIC but decent. They were cheap and I didn't know anything about maping and all that. I can make n design Subwoofer boxes to specs for car's but this is a whole new ball game. I'm willing to piece n solder crossover but I don't understand what each part is. I get the basic Layout of the blueprint of one just don't know what each piece is. Thank you for all your help and what ever I end up doing will be posted on new builds and you guy's can give me hints n such. Thanks again I'll keep you posted.


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## 1Michael (Nov 2, 2006)

Post the Xover here and someone will help you define what the parts are and what you need to buy:T


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