New 2-channel DIY speaker project

[gatemplin]

I have started a new DIY project with a lot of help from my friend Jon Hancock. This is the new project diary I will use to document the progress. There aren't many DIYers here, but maybe I can change that. ;)


The new project is a full range 2-way design using a Seas tweeter and the Adire Audio Extremis midwoofer.

The Seas 27TDFC tweeter is a great performer for this application and is popular in high end audio designs. They are used by Joseph Audio and Reference 3A to name a couple.

Here is the Seas:

http://seas.no/Product%20bilder/27TDC.jpg

The Extremis6.8 is a high tech midwoofer. It uses a dual gap motor (XBL^2)with a copper shielded pole piece. It has massive excusion and low distortion down low compared to the Scan Speak 8545. Here (http://www.adireaudio.com/Files/Extremis6.AVI) is the Xmax video:

Here is the Extremis:

http://www.adireaudio.com/images/Extremis%206%20Image.JPG

[michael_w]

Cool... where are you getting your parts from?

[gatemplin]

Originally posted by michael_w
Cool... where are you getting your parts from?

Thanks,

The Adire Audio Extremis6.8s are available from www.creativesound.ca

I'm buying the Seas and crossover parts from www.Solen.ca

[gatemplin]

The speaker design goal is flat frequency response, huge bandwidth, ultra low distortion and great off-axis response. The transient response will also be excellent.

The tradeoffs to achieve these goals are efficiency, size, cost, and max output.
They are going to be around 80 dB efficient.

The most important part of the design is the brain, the crossover. Jon is going to design this one using an 8th order Linkwitz-Riley design, modified with Cauer elliptic filters. Jon has been designing speakers for about 30 years. He is a published designer and a member of the Audio Engineering Society. I'm really lucky that he has been helping out with this hobby. He is an EE, but does this for fun.

The crossover point is going to be very low. Probably 1kHz even. The Seas can handle that because attenuation is so high in this design.

[gatemplin]

My version of the project will be an EBS box. 37L tuned to about 29 Hz. The anechoic F3 is 28 Hz according to Unibox. The in room F3 should be closer to 22 Hz.

[gatemplin]

Here is a AutoCAD drawing of the box I am building. I am using a 3" flared port about 15" long which is why the cabinet is so deep. The box is made from MDF, butcher block and birch ply wood in varying thicknesses from .75" to 1.25".

Edit: CAD drawing in next post.

[gatemplin]

EBS box.

[michael_w]

Looks like an interesting project. Kinda makes me want to get more into diy :D ... but I have a lot of learning to do before I start.

[gatemplin]

Originally posted by michael_w
Kinda makes me want to get more into diy :D ... but I have a lot of learning to do before I start.

That's why I started this thread. I hope to spread the disease. ;)

The best way to get into DIY is to build a kit or copy a plan. I did a few of those to start. It builds your confidence and you learn a lot. And you are guaranteed good results.

There are tons of great sites and books. The Loudspeaker Design Cookbook by Vance Dickason is considered the DIY bible.

PM me if you want recommendations for kits, websites, books etc.

[michael_w]

I'll do some more reading then get back to you on that one. I'm contemplating a sub but I'm not sure just yet.

[gatemplin]

This is probably the final crossover for the project. 8th order at 1.2 kHz. Jon just finished it.

It's a Linkwitz Riley based design with Cauer-elliptic filters modifying the transistion bands to achieve about 8th order attenuation.

Here is the crossover schematic:

http://audioworx.virtualave.net/Extremis27TDFCSchm.jpg

Here is the frequency response. There are room interactions and not much smoothing. We're not selling them so there is no need to make it look pretty.

http://audioworx.virtualave.net/Extremis27TDFCSPLMAG.jpg

I am so glad Jon is helping me out with the crossover design. I tried getting these drivers flat but could figure it out.

He did a great job and I cant wait to build and listen to them. The roll offs at the top and bottom are irrelevant. These are flat from 30 to 20k anechoic.

[gatemplin]

Here is the off axis response graph by Jon.

http://audioworx.virtualave.net/Extremis27TDFCSPLPR.jpg

Very flat through the crossover, me likey.

I'm ordering the parts tomorrow and finishing the cabinets. Trying to get these ready for a DIY meet Saturday.

[BlueMDPicker]

Fascinating, to say the least! I'll be watching as your concept comes to fruition (and wishing I had the knowledge, plus the facilities, to undertake such a wonderful project.)

Mike

[gatemplin]

Thanks Mike,

Most of the knowledge and work is from my friend Jon. I help out as much as I can. This has been a great learning experience for me.

Here is the front baffle layou designed in Baffle Diffraction Simulator by Jon, I drew it in AutoCAD. I'll be cutting up the baffles and making the tweeter housing tonight. Hopefully paint tomorrow, then crossover work Thursday and Friday.

http://htguide.com/forum/attachment.php4?attachmentid=2481

[Toxis]

Originally posted by gatemplin
There are tons of great sites and books. The Loudspeaker Design Cookbook by Vance Dickason is considered the DIY bible. I have this book and all I'm going to say is... wow. I haven't even got that far through it but I'm learning way more than I thought I would being this far into it.

I've been wanting to try some DIY speakers but I don't have the tools or facilities to build the enclosure. Plus, the part that I'm VERY green about would be the crossover network. That makes me go all crosseyed. Hopefully when I buy a house next year, I'll have the area to do something like this and by then, I'll have the knowledge to feel comfortable with a task like so.

[gatemplin]

I placed my order for the crossover parts today. I am using all Solen Perfect Lay 14 gauge air core inductors except for one. And all Solen Fast Caps polypropylene capacitors. Hopefully they will ship tomorrow so I can have them for the weekend DIY meeting.

If anyone is thinking of building this project figure between 600-700 US for the parts including wood. Not cheap, but this is a good design. Many months of work went into this. If you like to build things, and when you consider the performance, these things are bargains.

This is a new animation from Adire of the motor in the Extremis6.8

http://www.adireaudio.com/images/X_68_Motor_Animation.jpg



http://www.adireaudio.com/images/X_68_Motor_Assy_Cut1_small.jpg

[gatemplin]

I finished the speakers last night and brough them to a DIY meeting today.

I think they sound amazing. It is really nice to finally hear something that I (and Jon) worked so hard on.

They were powered by a DIY SS pre amp and a Bryston 3B power amp.

[gatemplin]

Here is a pic of the front setup. The crossovers are on the floor. They weren't going to fit inside, not even close.

[gatemplin]

This is a pic of the left speaker and a better look at the 8th order LR crossover.

[gatemplin]

Here is a pic of the DIY crew. That's me on the far left.

[gatemplin]

Here is Dave's instant crossover prototyping rig with the horns in the back.

[BlueMDPicker]

Very nice work! I guess you could hide the crossovers in the stands?

[dorokusai]

Outstanding!

[gatemplin]

Thanks guys,

I think I will incorporate the crossovers into the stands somehow. I have to figure out what size the cabinets will be first. No hurry though.

Here is a pic of the RCA field coil horn. Pretty cool I think. VERY efficient. Powered with a gain clone.

[gatemplin]

Here is proof that the RCAs go loud. Thats me with Chris plugging his ears in the background with the music at about 105 to 110 dB. It was painful.

[gatemplin]

Here is a pic of Fred's speakers. These looked and sounded beautiful. The woodwork was incredible, I'm very jealous. Raven ribbon and Seas Excel midrange.

[Zero]

First,

Jeez you all have HUGE heads. Obviously they are put to good use.. a lot of great designs. Yours looks very well thought out from what little I do know. You should be proud bud! !! Thanks for sharing.

[michael_w]

They look great gatemplin.... didn't expect the crossovers to be so massive but it'd be pretty original to have them built into the stands or something. Kind of like a tower bookshelf speaker.

I think I will pop by the library sometime soon and pick up that Loudspeaker Design Cookbook while I have some free time to read because of Spring Break..... WOOT. I told my boss I was "going away" and wouldn't be able to work at all during spring break :D . I need a break from doing 25-30 hour weeks at work and going to school so maybe this will be it :p .

[gatemplin]

Thanks again for the compliments guys.

I really can't articulate how much I like these speakers. I didn't realize speakers could sound this real.

[BlueMDPicker]

I think we need a speaker swap program! ;)

Put me first on the list, please.

Graham, what do you use to drive your new creations? Did the finished project end up in the 80 db efficiency range as you anticipated?

Mike

[gatemplin]

Originally posted by BlueMDPicker
I think we need a speaker swap program! ;)

Put me first on the list, please.

Graham, what do you use to drive your new creations? Did the finished project end up in the 80 db efficiency range as you anticipated?

Mike

Thanks Mike.

I use a Sansui AU999 integrated from 1970. The outputs are modified from the one in the pic to take banana plugs instead.

http://sansui.us/images/MySansui/Aaron/AU999_Aaron_02.jpg

The efficiency is quite low, but they do go plenty loud. 80 dB is not as bad as it sounds. We use almost full baffle step compensation, which makes the speakers sound very warm and full even at low volumes. I listen at least 3 dB quieter with these speakers because they are so clear. I have played these on a 50w Harman receiver and it did a fine job aswell.

[gatemplin]

Here is a pic of the back of the speakers. You can see I added a 3" flared port instead of the old 2".

[gatemplin]

Here is a better pic of the front baffles. I decided on the stands I am going to build. I will make them so that you can see the crossovers inside the stand.

I also have tweaked the crossover a little. I am going to add a switch so that I can change the sound depending on the music and room.

[michael_w]

Here is a better pic of the front baffles. I decided on the stands I am going to build. I will make them so that you can see the crossovers inside the stand.

Oooo I'm not sure how well it would work but stands made out of plexiglass encasing the crossover would be cool....

[gatemplin]

My father suggested the same thing. I have a couple ideas on how to showcase them. It will come down to what finish I decide on.

[beardog03]

very nice....

There are a lot of talented people around here...

do they sound as good as they look..?

[BlueMDPicker]

Graham,

Could you show us your shop area? I'm a tool junkie as well as an audio junkie.

Mike

[gatemplin]

Originally posted by beardog03
very nice....

There are a lot of talented people around here...

do they sound as good as they look..?

Thanks.

Yes they sound amazing. The crossover, which is the most important part by far IMO, was designed by a genius (Jon Hancock), and that is no overstatement.

They are very clear and smooth. I've measured them and they are very flat, which was a challenge with these drivers. The strong suit of these speakers are low distortion and wide frequency response. I would say they sound warm, especially with the Sansui.

Here is what my friends said:

Byron:

"Yeah, yesterday was fun! And I think there wasn't a person there
who didn't like your speakers immediately! ... I may in the future have some questions regarding those speakers
- hope ya don't mind"

Mehai:

"Excellent people. Really. I will be short this time. Graham's speaker are very good. "

Chris:

" Love at first sight? Something is wrong at the meet yesterday. I went to bed thinking about it and when I woke up this morning first thing came to my mind. *****! it is troubling my mind

It was Graham's speakers! I think I miss them already. Can I have them back for 5 years to do the long term reliability test for you?"

[gatemplin]

Originally posted by BlueMDPicker
Graham,

Could you show us your shop area? I'm a tool junkie as well as an audio junkie.

Mike

Sure. I'll get some pics the next time I borrow my brothers camera. I'm a tool junkie too. I used to be a mechanic.

For speaker building I use a plunge router, jigsaws, circular saw, and table saw.

[Willow]

Originally posted by gatemplin
Thanks.

Yes they sound amazing. The crossover, which is the most important part by far IMO, was designed by a genius, and that is no overstatement.

They are very clear and smooth. I've measured them and they are very flat, which was a challenge with these drivers. The strong suit of these speakers are low distortion and wide frequency response. I would say they sound warm, especially with the Sansui.

Here is what my friends said:

Byron: "Yeah, yesterday was fun! And I think there wasn't a person there who
didn't like your speakers immediately! ... I may in the future have some questions regarding those speakers
- hope ya don't mind"

Mehai: "Excellent people. Really. I will be short this time. Graham's speaker are very good. "

Chris: " Love at first sight? Something is wrong at the meet yesterday. I went to bed thinking about it and when I woke up this morning first thing came to my mind. *****! it is troubling my mind

It was Graham's speakers! I think I miss them already. Can I have them back for 5 years to do the long term reliability test for you?"


I hope to add a quote this summer!! ;)

[gatemplin]

Sure, I'll bring them over. I just finished tweaking the crossover today. They sound lovely. Very clear and full range.

Here is the final version:

http://audioworx.virtualave.net/Extremis27TDFCSchmA.jpg

[gatemplin]

Since I recently decided that I am going to move away to go to school for 5 years, I am making more portable cabinets for my speakers.

I also just got a new camera so I will be able to post the progress.

These will be about 14L sealed and will not dig as low as the old cabinets. I am adding cement to the inside walls to reduce panel resonances. The cabinets are made of at least 3/4" MDF. I am going to round over all the edges and then paint with black textured paint.

[gatemplin]

Here is one of the new cabinets. You can see the baffle recesses and if you look closely the tweeter has its own mini chamber to seperate it from the pressure created by the woofer.

[gatemplin]

Here is the back of the baffle. There is a ring where the woofer is mounted and it is rounded over to reduce reflections back onto the cone. I have started to add the cement to the front baffle.

[ND13]

Very nice work. In that picture showing the backs and 3" port, did you make the one's with the emit tweeter also?

Noel

[gatemplin]

Originally posted by ND13
Very nice work. In that picture showing the backs and 3" port, did you make the one's with the emit tweeter also?

Noel

Thanks. No, those little speakers were made by my friend Fred. Those speakers were very beautiful. They performed well, nice and clear, but obviously lacked extension. I think those are 5" Seas Excel midranges. The design was by Dennis Murphy, and I think David Ellis also had something to do with the design.

[gatemplin]

It's a long weekend so I have some more time to work on this project.

Here is the first pic. Rough front baffle on, ready to be flush trimmed.

[gatemplin]

The baffle after flush trimming with the router.

[gatemplin]

The holes are drilled and the baffle is ready for the driver recesses using a router and cirlce jig.

[gatemplin]

Here is the front baffle after the recesses.

[gatemplin]

Now the holes are cut out with the jigsaw. Using the circle jig does a better job but it doesn't matter and the jigsaw is faster, less dust too.

[gatemplin]

Here is the test fit of the drivers. Perfect fit I think. I finished the tweeter enclosure and will try to get some cement in these speakers tomorrow.

[gatemplin]

Here is the left side cabinet done with the drivers being test fit. Good enough for my house.

[michael_w]

Lookin good.... they should sound great. I've heard a few diy speakers using that extremis and they are quite impressive.

[VR3]

Awesome work dude! Really awesome...

That Extremis is sweet.

[gatemplin]

Thanks guys. I appreciate it. I didn't have a lot of time to work on the speakers today but I made a little progress. The Extremis is really sweet. If you need a small pair of bookshelves yet still need the low end, these drivers are the way to go for sure. The tweeter is really nice too. Very clear, no sibilance of course and great dispersion and imaging.

Here is a photo of my assistant. She is mixing the cement for me. Hopefully I have the cement work done in a few days (fingers crossed).

[gatemplin]

Here is a shot of the cement on the sidewalls, not quite dry yet. I rotate the boxes as soon as the old cement starts to set. The cement bonds very well with the MDF, it wont crack off. This is basically like a cinder block.

My brother picked the enclosures up before they had cement in them and said "Wow these are so heavy", then I told him about the cement. :D

You can get a good look at the tweeter's own enclosure in the pic.

[madmax]

gatemplin,
You are a mad scientist. No two ways about it... Very nice!
madmax

[gatemplin]

gatemplin,
You are a mad scientist. No two ways about it... Very nice!
madmax

:D Thanks, not the first time I've been called that.

Almost all the cement work is done now. I'm working on fitting the giant crossovers into the new little boxes today before work. I've decided on what to do for stands. The base and top plate will be painted textured black like the speakers with a hollow clear pine center post filled with sand.

Attached is a pic of the crossovers.

[gatemplin]

Dang! They aren't even close to fitting after splitting the crossover into two peices. Maybe three boards will fit, but that will be a lot more soldering.

[gatemplin]

I tried smaller boards and just barely got the crossovers in. Hopefully all the solder joints are good because I wont have access to the boards unless I cut the speakers open :eek: . I will know for sure when I redo the acoustic measurements to make sure everything is wired correctly.

I also added cement to the rear wall today. It's the first layer. I want to add the cement slowly because the moisture might make the MDF swell. Hopefully all the cement work will be done tomorrow.

I rounded over all the edges with the 3/4" router bit. It makes the speakers appear slightly smaller I think. I still have a lot of sanding to do. Then filler and paint.

BTW the final dimensions of the enclosures are 17" tall by 12" deep and 10" wide.

[gatemplin]

Here is a link to another Jon Marsh design. He did a design for AudioXpress magazine called and Unorthodox Two-way. The design used a Vifa XT25 (similar to the LSi) and an almost 9" woofer from HiVi called the M8a. There have been several versions of this design. Here are some pics from a version of the design that a fellow Canuck made. I'm floored.

The same Cauer-Elliptic filter was used on my speakers. Check out the crossovers.

http://www.htguide.com/forum/showthread.php4?t=3606&page=7&pp=35&highlight=m8n%2A%2A

[michael_w]

The ones paul h made are absolutly stunning. I'd love to make a pair like that but need to read up on building crossovers first :p

[gatemplin]

The ones paul h made are absolutly stunning. I'd love to make a pair like that but need to read up on building crossovers first :p

Yeah I love the curved sidewalls and the dark stain with the huge gold woofers.

The crossover isn't too hard to build. Soldering takes a little practise but other than that you just copyh the layout.

[gatemplin]

I just measured the speakers in Speaker Workshop. Everything checks out. I'll post the frequency response as soon as I can. I am so relieved, if anything went wrong, I would have had to cut the boxes open to get at the crossover boards.

[gatemplin]

Here is a quick frequecy response plot. This is quite flat but it is not the whole story. A on-axis FR plot is like the peak horsepower number. It's interesting, but over rated and only tells a small part of the story. You still dont know + or - 15, 30, 45 degrees horizontal and vertical. It doesn't give any indication of group delay, distortion, decay, etc etc. The speakers should be flat from about 50 Hz to 30 kHz.

Anyway, this was done far field ungated MLS at a distance of about 50 cm. I used a RS meter and Speaker Workshop. The RS meter is limited in accuracy and is only good up to several thousand Hz. I use this mainly to make sure the crossover is working properly and everything is wired correctly.
The results are 1/3 octave smoothed.

I'm very happy with this. Now it's on to finishing the cabinets.

[gatemplin]

Here are some pics of the weigh in. It measured exactly 50.0 lbs! :confused: No wonder cement isn't very popular for speaker enclosures.

[tecmo04]

looks like a hernia and a half. but heres the real question, how do they sound??

[michael_w]

With cement won't sound waves bounce inside and cause lots of resonance problems or is it just so damn dense that it absorbs everything. I'm just thinking about when you're in a concrete building and what happens when you yell.

[gatemplin]

looks like a hernia and a half. but heres the real question, how do they sound??

Good. :D But dont take my word for it. See below


I was at the Toronto DIY meet where these were auditioned extensively. The room there was quite large, and these speakers did very, very well. IMO they were the best speakers at the event, though in a smaller room the Dennis Murphy Seas excel + Ribbon tweet design would have given them a run. That right there should tell you something about the pedigree of the speaker. Kudos to Jon and Graham on these , I predict they will keep you happy for a long time.
and

http://www.polkaudio.com/forums/showpost.php?p=277714&postcount=38

This version will sound almost identical to the old version, other than this is sealed. The old cabinets were very substantial aswell. Butcher block and heavy bracing. They were just too big.

[gatemplin]

With cement won't sound waves bounce inside and cause lots of resonance problems or is it just so damn dense that it absorbs everything. I'm just thinking about when you're in a concrete building and what happens when you yell.

You dont end up with any resonances, nothing is resonating. But you're right, concrete or cement is poor at absorbing acoustic energy. You do, or can have reflections and standing waves (no standing waves in these boxes though). For that I am lining the box with polyfil, and lots of it. You dont want reflections hitting the back of the cone, it is inevitable, but you try to minimize it.

After doing more research on this, there are others who have lined their enclosures with cement. Works very well, except for the weight issue. Having two materials bonded together like this works even better for controlling resonances.

[michael_w]

Sounds like a good idea. Who cares how much they weigh once they're in place :p Polyfil should do well in taming the air bouncing around inside a bit. You could probably help kill any standing waves by rounding the inside corners with cement too.

[gatemplin]

You could probably help kill any standing waves by rounding the inside corners with cement too.

The inside corners are rounded, but non-parallel walls or ratios of 1.62:1 help as well.

I dont have to worry since the entire enclosure is full, really full of huge 14 gauge inductors and caps bigger than D cell batteries.

[michael_w]

The inside corners are rounded, but non-parallel walls or ratios of 1.62:1 help as well.

Good to know for future projects thanks.

BTW where do you live? I'm asuming somewhere in canada because of the trailor park boys thing. I'm in steveston (BC). Just curious cause if you're close I'd be cool to check these beasts out and give them a listen.

[gatemplin]

Good to know for future projects thanks.

BTW where do you live? I'm asuming somewhere in canada because of the trailor park boys thing. I'm in steveston (BC). Just curious cause if you're close I'd be cool to check these beasts out and give them a listen.

Yeah I'm a trailer park addict. I live in Toronto now, but I'm moving to Waterloo in a couple weeks.

[michael_w]

Mmmm that's too bad. Good luck with the move.

I love the show too but I always seem to be busy and don't have time to watch it when it is on.

[gatemplin]

Mmmm that's too bad. Good luck with the move.



Well I'm just going off to school. Not a big move, just gotta pack some clothes and speakers! ;)

[gatemplin]

I'm finally done with the wood putty and 220 grit sanding now. Ready for the final base coat of satin black acrylic. Then I'll spray on some polyurethane clear coat.

[gatemplin]

I didn't get them done in time unfortunately. But at least they work, which is the most important thing. Afterall, I'm in engineering, not arts. :p

I might get the painting done on one of my trips back home.

[Willow]

Hey Graham, those are looking very nice. I will have to wait till we meet either in TO or here in Ottawa to listen to those. Looking forward to it.

[michael_w]

So now that they are all purty and functional what do you think them?

[gatemplin]

Hey Graham, those are looking very nice. I will have to wait till we meet either in TO or here in Ottawa to listen to those. Looking forward to it.

Hey JF,

I plan to bring them up to Ottawa some time. I'll PM you when I know. Hope everything is still going well for you two.


So now that they are all purty and functional what do you think them?

Well they sound great, at least everyone says they do. I tweaked the crossover to get it just the way I like it. I am very happy with them, it was a very fun project.