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My first ever (speaker) build

James said:
First of all, can I applaud your enthusiasm and cracking into your first DIY build. I personally started that journey of mine over 20 years ago when I wanted a pair of top-shelf loudspeakers on beer budget. I used online crossover calculators to derive the filter network. They didn't turn out too badly, but they weren't great either.

Second, it sounds to me like you're attempting a design of your own. That's probably the best way to learn about DIY loudspeakers. If that is your inclination, I highly recommend you borrow or buy a copy of Vance Dickason's Loudspeaker Design Cookbook; particularly if you want to know how to optimise a DIY design and understand how the various T/S parameters work together.

Third, you might get addicted and this may not be your only DIY loudspeaker. You will be encouraged by your first results, but I can almost assure you that you'll want better. If that turns out to be the case, don't expect DIY loudspeakers to save you money. Instead, it will be a fantastic learning experience that you will find expensive, challenging but enjoyable and rewarding in equal measure.

Take your time, think things through, exercise great care with power-tools such as a router, and don't be afraid to ask for advice if you're stuck on what to do. Good luck!
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Thanks, that's both encouraging and a little worrying, at the same time ;o)
 
Puggie said:
There are a couple of variants of the Devore Oseries clones on diyaudio if you haven't seen them and Seas' own version with the bit T35 tweeter:


I think it's a great start point for a DIY, relatively simple cabinet, very simple crossover and easy to tweak to experiment and see how changes affect things. I would suggest a 4 wire speaker terminal plate and look to trial the crossover component outside the box until you settle on a design.
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Thanks, yes, that was one of the sites I got the inspiration from along with a similar thread on the Steve Hoffman site
 
Go for it. You'll learn what you need when you needt to. Make the wood as good as you can and thery may ever resell if you don't like the sound! :)
Good luck
 
With a 25cm woofer, I wonder if it might not be a good idea to leave space on the front for a midrange? One never knows what you may feel like doing in the future.
 
PaulMB said:
With a 25cm woofer, I wonder if it might not be a good idea to leave space on the front for a midrange? One never knows what you may feel like doing in the future.
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Retrofitting an additional (midrange) driver is not trivial for three reasons:
  • Routing a new hole and rebate on an affixed baffle is tricky, messy
  • Mids usually need a separate sealed rear enclosure to isolate them isobarically from the woofer, and it's a guess how much space to allow for
  • The crossover network will need a complete redesign if it is to have any chance of bettering the original 2-way
If, as I predict, the OP gets addicted to this esteemed hobby, I'm sure he will have loftier ideas involving more drivers. By then, he should have read a few recommended books on the subject, invested in measurement and modelling soft/hardware, and amassed a full workshop of woodworking tools, material supplies and a collection of caps, coils, and spare drivers. Ask me how I know.
 
James said:
Retrofitting an additional (midrange) driver is not trivial for three reasons:
  • Routing a new hole and rebate on an affixed baffle is tricky, messy
  • Mids usually need a separate sealed rear enclosure to isolate them isobarically from the woofer, and it's a guess how much space to allow for
  • The crossover network will need a complete redesign if it is to have any chance of bettering the original 2-way
If, as I predict, the OP gets addicted to this esteemed hobby, I'm sure he will have loftier ideas involving more drivers. By then, he should have read a few recommended books on the subject, invested in measurement and modelling soft/hardware, and amassed a full workshop of woodworking tools, material supplies and a collection of caps, coils, and spare drivers. Ask me how I know.
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No, not trivial at all. When I did this on some vertically shaped TL speakers I built a second box on top of the original cabinet to hold the tweeter and midrange (and blanked off the original tweeter hole.) And, as you say, the crossover has to be completely re-done.
I just thought if the OP is going to spend the next few years playing around he might find the original box a useful test-bench. I was also thinking that a 25cm woofer sounds a bit big for a 2-way, but bear in mind that I would consider myself lucky to have 1/100th of your practical and theoretical experience of these matters.
 
PaulMB said:
I was also thinking that a 25cm woofer sounds a bit big for a 2-way...
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I generally draw the line at 8" for a 2-way, but the Seas A26RE4 has a rather well behaved roll-off and is recommended for use up to 1,500Hz.

The Morel CAT378 with its horn loading and filtered appropriately (24dB/oct) can just about be pushed down to around 1,500Hz. Directivity of the woofer in the midrange could shift tonal balance with a slight dip in the midrange, but won't be an issue if designed and listened to on-axis.

In short, the pair should work OK.
 
One thing worth noting. With the modified Devore woofer, I'm pretty sure the phase plug moves the acoustic centre forward, combine that with a waveguide tweeter, and it should make crossover design easier, and phase tracking better.
 
I've only done a couple of cabinet builds but would stress that taking time to enjoy every step is so worthwhile. Measure twice, cut once is the mantra, and it so helps as one can think ahead and minimise errors. I received a massive amount of help on my Tannoy's from @cooky1257 for which I'm so grateful and would suggest that a few evenings waiting for replies and advice added a lot to the process. Actually cutting and sticking is such a small part of the process. I hope you enjoy every part of it and then enjoy the results!
 
steveinspain said:
I've only done a couple of cabinet builds but would stress that taking time to enjoy every step is so worthwhile. Measure twice, cut once is the mantra, and it so helps as one can think ahead and minimise errors. I received a massive amount of help on my Tannoy's from @cooky1257 for which I'm so grateful and would suggest that a few evenings waiting for replies and advice added a lot to the process. Actually cutting and sticking is such a small part of the process. I hope you enjoy every part of it and then enjoy the results!
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thank you, sound advice and something I shall continue doing whilst the thread runs

The cabinets are now cut to size and seem to fit together well, though some fettling may be required later. I was going to begin dowelling the top and sides next before doing something similar for the back and then when the drive units arrive next week will begin the work on the front baffle......
 
One thought is that it might be wise to bring the wires from the drivers out of the box, maybe through a temporary hole at the back, until you finalise the crossover. You may find you want to try different value components after listening for a while. The "given" crossover is all very well, but there are different rooms, different ears and different tastes in sound. I have a pair of DIY 3-way transmission lines, with which over many years James has given me precious advice, and just this morning decided to eliminate the capacitor and resistor in parallel with the woofer. (so now the woofer just has a coil in series). Right now I think it sounds better, but maybe in a few months I'll decide to tinker with it again.
 
Ugg10 said:
If you haven’t seen this yet there is a pdf by Planet10 on a range of box designs for the A26 woofer and a crossover for the CAT378.

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I'd be a little wary of Planet 10. He's a nice guy, but he paints little dots on woofer cones to supposedly improve the sound.
The Seas woofer can sound bass light in some rooms. It models with a lack of low frequency extension in a sealed box, so if you find it lacking, a port should improve things. I can upload a model with comparisons when I'm on my PC.
 
Fatmarley said:
I'd be a little wary of Planet 10. He's a nice guy, but he paints little dots on woofer cones to supposedly improve the sound.
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He makes a whole range of interesting and well thought out speakers which have been well received. I see no reason at all to be wary of him. I haven't heard his modified cones so I have no idea if it improves the sound. Jury is out on that, but he must do it for a reason.
 
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