My Winter Project

[talladega]

Well after having planned to build new speakers for about a year now I finally have decided to go for it. I ordered the parts this week.

The speakers I'm building are these: http://www.lonesaguaro.com/speakers/...t/amethyst.htm
Price was in my range and they seem to be quite good. These will be for our bedroom hooked up to the raspberry pi squeezebox player I built earlier this year.

I'm planning on making a few changes to make them kinda like these speakers:https://www.htguide.com/forum/showth...l=1#post571425 and



Having them angled back a bit and the angles cut in the face of the wood.

I did bit of a mock up in Sketchup.

Image not available

I'm pretty sure I have most if not all of the wood I need for these speakers as well. The only thing I need is wood for the front of the speakers.
I was thinking of going with Padauk or maybe Bloodwood for the front. I've found a place somewhat locally I could get it from. I'd rather import from the US as that would be cheaper, but I'm not sure about the laws if thats allowed to be brought into Canada.

One thing I'm a bit uncertain about is doing the holes for the speakers. I have a router, but not a plunge router. Cutting the holes for the speakers isn't too bad but how do I do the recess for the drivers without a plunge router and how hard is that going to be to do it in a hardwood like Padauk or Bloodwood?
Is a recess even that necessary or is it mainly for the looks?


Anyways, I should have my parts next weekend and then I can slowly start to work on them. I'll update this as I progress

I've been asked to build a somewhat large (20"x27") photo frame for my wife's massage therapist so that will probably take priority since I'll be getting paid for that. I've been wanting to make photo frames for myself actually sometime so this will get me a good start in it. I have some nice scrap oak pieces I'll be using. A bit of a shame that they will be painting it and cover up that nice oak, but thats ok. Wood doesn't cost me anything. We've got a huge bin of scrap oak pieces that we got for a few bucks. I'll have to look if there is some kind of jig I can make to do the photo frame that way I can easily make more later on.

[cjd]

Making changes like you suggest also will need crossover tweaks - you're changing the time alignment by altering the baffle slope, and you're changing edge diffraction by altering the baffle shape.

Driver recess will also fiddle with diffraction - for that mid-woofer, it may also be important to keep the backside of the driver breathing at its best in the box. You can do this with a rabbet bit - I have this set and it's been quite nice.

Otherwise sounds like an awesome project. I'd hate to see your box designs see less than ideal results by not having a properly optimized crossover.

[JonW]

Hi Talladega,

Cool project! I’m making those Schlafmutzes, so, of course, I like the look of yours.

I’m with cjd. All the changes that you propose will have negative effects on the sound quality- sloping the baffle, cutting the facets, and not recessing the drivers. Maybe even having that speaker stand being larger than the cabinets at the front. If you want to see how much the baffle slope and facets influence things, I took some measurements of various configurations and the results were pretty different. Check out pages 10 and 11 of this thread:

https://www.htguide.com/forum/showthread.php?25031-The-Spassvogel-MT-project-design-and-progress-(ScanSpeak-6600-amp-18W-8531)/page10

So for best sound quality, I would recommend keeping with that original Amethyst design. Or find some speakers already designed with the look that you want. (The Schlafmutzes are way more expensive than the Amethysts so I am not pointing you there.) But, really, it’s a DIY speaker project. The priorities are up to you. The speakers you modeled will certainly look super cool.

I know that most people discourage the use of real woods for speakers and use plywood or MDF, etc. Due to cabinet resonances and also expansion/contraction issues and the resulting cracking with season changes. However, these speakers are so small that such issues may be less important than typical.

For build tips, I wrote out a complete step-by-step for the Schlafmutze cabinets, post Groups on page 1 of the thread you linked to.

[knowledgebass]

If you don't have a plunge router, you can start your routes with a Forstner bit to match the outside edge and give the fixed base router a starting point.

[talladega]

Thanks for the tips and ideas guys.
Using the forstner bits and rabbet bits sounds like that should work. I think I have those or atleast they are cheaper than getting a new router

When you say that having the speakers angled (the back is angled as well to keep same volume) will have a negative affect, how negative are you talking? I know you cant say exactly what it will do but will it be enough to make a really noticeable difference?
To me, I want good sound quality, but I also want some nice looking speakers and I'm willing to make slight sound quality sacrifices if I can make them look a bit better. Afterall these are 90% being used for an alarmclock/sleepmode.

I saw your tips for the Schlafmutze cabinets. Got it bookmarked! Will be very helpful.

I think what I might do is because these don't use a lot of wood is maybe build one slanted and one non slanted and see how they sound.

I would imagine that the crossover should be placed at the bottom of these cabinets? Looks like that would have the most room.



Thank guys!

[JonW]

Thanks for the tips and ideas guys.
Using the forstner bits and rabbet bits sounds like that should work. I think I have those or atleast they are cheaper than getting a new router

For what it’s worth, I used a Jasper jig and router to cut the tweeter rabbet. Then I used a Forstner bit to make the main hole for the tweeter.

I would imagine that the crossover should be placed at the bottom of these cabinets? Looks like that would have the most room.

Sounds good. As long as you don’t stick the crossovers on the back of the magnet, you can put them anywhere that you want. Try to keep the parts away from the woofer magnet if you can. But there is just not going to be much space in there. So do what you can. Personally, I don’t like the idea of mounting the crossovers on the sides or top of the cabinet. Because if I keep the speakers for many years and the adhesive fails, the crossover will fall down.

When you say that having the speakers angled (the back is angled as well to keep same volume) will have a negative affect, how negative are you talking? I know you cant say exactly what it will do but will it be enough to make a really noticeable difference?
To me, I want good sound quality, but I also want some nice looking speakers and I'm willing to make slight sound quality sacrifices if I can make them look a bit better. Afterall these are 90% being used for an alarmclock/sleepmode.

Hard to say. They’ll still make sounds and be audible. It depends on how much sound quality is at a premium for this project. It’s DIY so it’s totally your choice. cjd and I tend to be snobby about how our speakers sound. OK, I’m the snob. And cjd is refined. Is that less insulting? DIY speakers mean that you get to make the tradeoffs. Cooler looks for less sound? Great if that’s what you want. Ugly speakers but the best sound ever? That can be called for, too. Or not. To be honest, I did not like the slanted and faceted look in the beginning. I went that way because the measurements showed it to be better. After I built the speakers, the look grew on me.

Everything in life is relative. Are you listening to the tiny speakers in your laptop now? Then the Amethysts changed to be slanted will probably sound much better in comparison. Are you an audiophile snob? Then the lumpy frequency response and the lack of tweeter-to-woofer phase matchup might bother you.

Do you want a more quantitative answer? Look at this plot I measured. It’s the same tweeter in the same cabinet, measured with the same baffle straight and then angled back. Would that difference bother you?

[talladega]

I'm definitely not an audiophile snob. When it comes time when I can build some Statement Monitors (and hopefully Statements) I don't think I'll be doing any trade offs for quality. For these speakers, I think you've help give me my answer. I'll go with slanted the difference it will make I wont notice i'm sure. If it sounds crap I'll just rebuild anyways

These will be replacing speakers from a $50 Home Theater in a Box type set. ANYTHING will be better than those! lol

Thanks for your help guys. I can't wait to start working on these.

[cjd]

The problem is it's hard to know how any one speaker will work off-axis, especially vertically, unless it is measured. In some of the Nebbiolo crossover exploration I've done, when I go with a vertical baffle and no crossover change, some variations pick up a ~15+dB null and a sucked out midrange (though I need to be more accurate with the z-axis data so this may not be fully accurate) - at any rate, its just something we can't predict with surety. It could be good enough, but it could be real audible trouble. It's entirely possible that the chamfers will help.

I don't think we're trying to say "don't do it" but simply mentioning the possibility it might not be perfect. I suppose worst case, if it sounds bad, you can easily ship a box to someone for an updated crossover design. It looks small enough to not be a problem.

[JonW]

The problem is it's hard to know how any one speaker will work off-axis, especially vertically, unless it is measured. In some of the Nebbiolo crossover exploration I've done, when I go with a vertical baffle and no crossover change, some variations pick up a ~15+dB null and a sucked out midrange (though I need to be more accurate with the z-axis data so this may not be fully accurate) - at any rate, its just something we can't predict with surety. It could be good enough, but it could be real audible trouble. It's entirely possible that the chamfers will help.

I don't think we're trying to say "don't do it" but simply mentioning the possibility it might not be perfect. I suppose worst case, if it sounds bad, you can easily ship a box to someone for an updated crossover design. It looks small enough to not be a problem.

15 db? That's a pretty big change! The comparison that I posted above shows that things can get pretty lumpy moving between straight and angled. But I wasn't in the 15 db range. It's not a problem as long as it's accounted for in the measurements and crossover.

[JonW]

I'm definitely not an audiophile snob. When it comes time when I can build some Statement Monitors (and hopefully Statements) I don't think I'll be doing any trade offs for quality. For these speakers, I think you've help give me my answer. I'll go with slanted the difference it will make I wont notice i'm sure. If it sounds crap I'll just rebuild anyways

These will be replacing speakers from a $50 Home Theater in a Box type set. ANYTHING will be better than those! lol

Thanks for your help guys. I can't wait to start working on these.

Sounds great. I think that you'll be in good shape. Your expectations are in check so you won't be coming back, complaining to us that the speakers don't sound like a $25,000 pair of somethings- because we lead you astray.

In exchange for this help, you are now obliged to show us how your project goes, with lots of photos. Good luck!

[cjd]

15 db? That's a pretty big change! The comparison that I posted above shows that things can get pretty lumpy moving between straight and angled. But I wasn't in the 15 db range. It's not a problem as long as it's accounted for in the measurements and crossover.

I didn't go through the full process of properly extracting z-axis numbers in this case since I was just sketching, so it's probable that some of that null was poor process. On the other hand, it prompted me to re-evaluate and land at an improved crossover anyway so who knows. I'll be more thorough soon enough - I'm working through finish coats on the veneer, but have one at a point where I can sit down and pull a lot more data. I'll be curious to see if the crossover I have works, or if some diffraction nulls have contributed to what appears to be a usable crossover, and I'll have more work cut out for me. I'll stop derailing this thread though

[JonW]

I didn't go through the full process of properly extracting z-axis numbers in this case since I was just sketching, so it's probable that some of that null was poor process. On the other hand, it prompted me to re-evaluate and land at an improved crossover anyway so who knows. I'll be more thorough soon enough - I'm working through finish coats on the veneer, but have one at a point where I can sit down and pull a lot more data. I'll be curious to see if the crossover I have works, or if some diffraction nulls have contributed to what appears to be a usable crossover, and I'll have more work cut out for me. I'll stop derailing this thread though

OK. I'll also refrain from derailing the thread. Except to say that I was interested to see how the measurements of slanted versus not had such a significant effect. Maybe even baffle diffraction was influenced. At any rate, I think that Talladega is in good shape. He won't have the best ever possible speakers with those components. But his expectations are adjusted, they will still play music, and they will look nice.

[talladega]

getting this thread back on raills.... :P

I believe I have the wood for everything but the fronts right now. I've been recording the dimensions that I need to cut so I'm preparing for that.
I'm hoping I can get to the store too pick up some Padauk sometime in the next month but i'll be able to do most of it without that so far.

Still working on the photo frame that I'm building. I made a 45 degree miter jig for the table saw on saturday. Took a while as we had to calibrate the table saw too. Now I just have some pieces being glued then I'll be trimming them down and building the frame. Hoping to get that done this week. If it goes well I'm hoping to make a few more for christmas presents.

Then I also have to help at my parents house to take all their kitchen cabinets out as they are getting the floor and counter tops replaced.

So my progress on the speakers is gonna be a bit delayed, but thats ok.

[JonW]

Sounds great. Get to it.

Do you think that, with these speakers being as small as they are, that 100% real wood will be OK? I know that expansion and contraction of wood as humidity and temperatures change can lead to cracking and such. But maybe with all the dimensions being small, it will be OK here? For my project, I used balletic birch ply and then veneered them. But using real wood was a consideration.

[talladega]

I think with just the front baffle being hardwood that it should be okay. Padauk is supposedly a very dense and strong wood. Also, the plans call for 1/2" and i'll be using 3/4". So i think strength wont be an issue. If a number of years down the road they have issues, i'll just redo them .