# Speaker DIY help



## Pav26 (May 17, 2013)

Hi all,

I'm very new to the whole DIY speaker building thing. I'd say I have a lot more experience in the subwoofer department (I'm almost done designing a new enclosure for my titanic driver). I thought that along with the DIY sub, I'd (try) to make some speakers to go with it, and try and learn how to successfully design/make my first speaker project! 

Basic Idea: 









Treble Unit: Dayton Audio ND20FB-4
Midrange Unit: SacnSpeak D7608/920000
Bass Units: Dayton Audio SD215A-88

Would this be a workable idea? I guess I need to work on a crossover design too - but I'm not sure where exactly to start :dontknow:


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## hddummy (Mar 9, 2007)

There are different XO design software packages or books out there if you really want to get into this. I don't want to stand in your way if you really want to learn that...its great. I personally didn't see that the time investment of learning XO design was worth it when I was building my DIYs. I recommend you evaluate the different kits out there. This way, all the driver selection and XO work is done and all you have to do is build the enclosures and XOs.


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## Pav26 (May 17, 2013)

Thanks for your input Matt, appreciate it! I have actually already studied the various kits out there, and I don't think anything interests me very much - hence the reason to go full DIY. I'm hoping someone who is experienced with designing xovers will chip in and 'guide me' or point me in the right direction when designing the correct one for my needs 

Anyone here who can give me some poimters/guidance would be much appreciated!


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## fschris (Oct 31, 2009)

I have tried to follow some xover design threads and they all end up go way over my head!!

I have a friend however that used some behringer units that are active xovers. seems to me like a good idea since you can have a world of options and are not stuck with one xover that you build. I am sure there are some cons such as each cost about 300 bucks and you would need 2 of them.


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## BoomieMCT (Dec 11, 2006)

If you can build a sub you can build a speaker from a kit. Designing a speaker from scratch is a whole 'nother animal. Here is my recommendation;

1. Buy the Loudspeaker Design Cookbook. Read it cover to cover. If you have time get the Master Handbook of Acoustics and read that too. These will both be good reference for the rest of your speaker building career so it is money well spent.

2. Play with design software to get an idea of how things mesh together. Unibox and the products from the FRD Consortium are free and are quite powerful.

3. Buy parts for one (1) speaker you design, and not too expensive of one (and probably a 2-way not a 3-way). Consider this speaker a throw-away to learn on. Build a box (don't bother making it pretty) and wire up your first design. Listen to it. 

4. Get a decent setup for REW (software is free, hardware will be about $150) and measure your build. Spend some time tweaking it. You'll probably need extra crossover parts for this. Play with different baffle sizes and driver layouts. Play with crossover points and slopes. Play with stuffing and port lengths.

5. Now that you have some background go back with what you learned and design the speakers you really want!

I wrote this not to talk you out of it, but rather to give you and idea how to ease into the hobby. If it ends up being something you enjoy you'll have leftover crossover parts and drivers to play around with before you know it!


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## Pav26 (May 17, 2013)

Thank you both for your input. fschris, I had a look and you're right - they cost a lot and I'd need more than one - though that is a good idea as I'm not limited to one option like you said.

Boom, that's a comprehensive write up you've got there. The books look fantastic, I'll be sure to try and source some up. I actually already have 3 left over drivers and 2 tweeters from some old TV speakers, meaning I could build a 2 way like you said. I've used them in free air before, it's a bit of a weird design - the tweeter connects to the woofer's terminals and well it just works without an xover. Will be sure to try and play around with it though! 

A fantastic write up - :thankyou:


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## BoomieMCT (Dec 11, 2006)

Pav26 said:


> Thank you both for your input. fschris, I had a look and you're right - they cost a lot and I'd need more than one - though that is a good idea as I'm not limited to one option like you said.
> 
> Boom, that's a comprehensive write up you've got there. The books look fantastic, I'll be sure to try and source some up. I actually already have 3 left over drivers and 2 tweeters from some old TV speakers, meaning I could build a 2 way like you said. I've used them in free air before, it's a bit of a weird design - the tweeter connects to the woofer's terminals and well it just works without an xover. Will be sure to try and play around with it though!
> 
> A fantastic write up - :thankyou:


Thanks. I've toyed around with open baffle (OB) speakers a bit. In fact, a set I made as a testbed kept getting tweaked and added on to and are now in my living room as my main listening speakers (there have been changes since I wrote that up). That being said I would not start with open baffle speakers as there are a few more variables to consider compared to a sealed or ported design. 

If you have speakers lying around see if you can find the thiele-small (TS) parameters for them online. If you can't, see if you can measure them (there are things you can buy to help). You'll need that info for the design part. Another great place to go to for drivers to play with is any big audio parts stores clearance bin (Parts Express, Madisound, etc.). They will usually have the TS parameters listed (whether they are correct is another story).


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## Pav26 (May 17, 2013)

BoomieMCT said:


> Thanks. I've toyed around with open baffle (OB) speakers a bit. In fact, a set I made as a testbed kept getting tweaked and added on to and are now in my living room as my main listening speakers (there have been changes since I wrote that up). That being said I would not start with open baffle speakers as there are a few more variables to consider compared to a sealed or ported design.
> 
> If you have speakers lying around see if you can find the thiele-small (TS) parameters for them online. If you can't, see if you can measure them (there are things you can buy to help). You'll need that info for the design part. Another great place to go to for drivers to play with is any big audio parts stores clearance bin (Parts Express, Madisound, etc.). They will usually have the TS parameters listed (whether they are correct is another story).


I'll be sure to try and catch up on your OB build sometime! I think I'm quite fluent in the designing section, I am used to modelling speakers (mainly subs, mind you) and just experimenting to get the best out of them with the given T/S parameters. It's the xover design knowledge I'm lacking. I'm good at soldering and understanding things like series, parallel etc. You're also right, I will need the T/S parameters for design - though I have no info on these small TV woofers/tweeters at all. Like you say, I might have to measure them with a multimeter. 

This might be a lot harder than I thought - it's a hobby, not a one off sort of thing - though I'm willing to get into the whole thing and get my hands dirty :work:


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## BoomieMCT (Dec 11, 2006)

With speakers (vs. subs) you are dealing with shorter wavelengths so you need to take into account the baffle step. That is basically where the wavelength gets long enough you stop getting a boost from the baffle itself. Sub frequencies are so low they don't really care about the baffle. Speakers that are meant to be near the wall or corner are affected by this less too.

With OB's you have another issue with the rear wave cancelling out the front wave (again determined by baffle size) resulting in a 6dB/octave roll off. Most designs I've seen either have a conventional sealed or ported woofer arrangement to deal with this, or they EQ the low end.

It's a fun hobby and there is no end to how much you can learn. I also think it is addictive - there was a time when all my family were getting speakers I designed and built for their birthdays and Christmas (I had no more room for them!).


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## Pav26 (May 17, 2013)

Now that I have some free time, it's time to get learning :T

Well, at least I know what I'm getting my friends and family for birthdays and Christmas!


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## fbov (Aug 28, 2008)

Without repeating some of the advice that's gone before, let me point out some fundamental probelms with your design. The Scanspeak mid looks wonderful but it's 92dB sensitivity. That's not a problem for the tweeter, at 90dB, because most designs have a little downward slope on the mid to achieve flat response. 

The problem is the SD215, while DVC, is native 4 ohms. Using two either gets you a 2-ohm speaker with sensitivity close to the ScanSpeak, or a 4-ohm speaker with 6dB of resistors on the mid and tweeter. Start with an RS225 and you get a better sensitivity match. 

Then, all you need is:
- impedence vs. frequency data, and 
- SPL vs. frequency data, in the intended enclosure
... and some SW to design a crossover. You can learn a lot about the process here:
http://www.pvconsultants.com/audio/frdgroup.htm

I have a measurement rig, I know how to use the SW, I've been through the FRD site, and I still build other people's " proven designs" because they sound so good the first time...

HAve fun,
Frank


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## Pav26 (May 17, 2013)

Thank you Frank, a lot of useful info there!

Since then I have made some adjustments to my design ideas. Following on from you pointing out the impedance issue (thank you) I have been recommended these drivers by a great UK audio components distributor - a SEAS CA22RNX 8" woofer. I have also changed the design from sealed to transmission line.

So far then (for one speaker)

2x Seas CA22RNX woofers (High Qts and low Fs for TL design)
1x ScanSpeak mid
?? Tweeter

I'm awaiting a reply from the nice guys at Audio-Components UK, for a decision on what tweeter will go well with these. 

I know you recommended the RS225, but I can't help but think that being in the UK that the Seas drivers and availability is a bit better due to personal circumstances  

Will defo read up on those links you gave me, too. Have I missed anything out - and more importantly, do you think this is a better option than the SD215?


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## fusseli (May 1, 2007)

There is some great advice in this thread for the starter DIY full-range builder. In most cases a skilled designer could pick whatever drivers and make them work, that's the fun part of DIY. How good the end result is, the expertise to produce a model/simulation that matches measurements, and how much trial and error it takes to get there is another thing. If you want a pair of awesome speakers to put into your main system tomorrow, then I'd suggest building someone else's proven design. However if you are patient and willing to learn then gather the tools of the trade (design software and measurement tools) and learn up!

For example, my own DIY towers are on their 4th crossover since their construction seven years ago and are just now to the point of being a decent finished design. If you take the time to learn first you should be able to get there much faster lddude:



BoomieMCT said:


> If you can build a sub you can build a speaker from a kit. Designing a speaker from scratch is a whole 'nother animal. Here is my recommendation;
> 
> 1. Buy the Loudspeaker Design Cookbook. Read it cover to cover. If you have time get the Master Handbook of Acoustics and read that too. These will both be good reference for the rest of your speaker building career so it is money well spent.
> 
> ...


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## Owen Bartley (Oct 18, 2006)

Pav, I think this thread would be worth taking a look at if you are still planning to design your own crossover.

http://www.hometheatershack.com/for...vices/68015-first-impression-dsp-minidsp.html 

I don't have any crossover design experience, but from Brad's comments in there, it seems like the miniDSP makes testing and tweaking a lot easier to do.


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## fusseli (May 1, 2007)

Active crossovers would be far easier to make adjustments and fine tuning on. The penalty is the higher cost and complexity, requiring the dsp and all of the additional amplifier channels.


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## Pav26 (May 17, 2013)

Whoops, I didn't realize I had new replies to this thread! :hide: Owen, thanks a lot for the help. I've Gone and bought some new mains (for now - I'm very content with them) but that doesn't stop me wanting to build some speakers in the future! 
I think a miniDSP is something I should really consider, especially because I'm about to go ahead with a DIY sub build...

And agreed. Active x-overs would be a tad easier to work with - but like you said fusseli, it comes at a cost (quite literally)


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