Building the RA-8

Tedp · « **on:** 28 Apr 2006, 04:59 pm »

Ok ... I've been thinking about building some new speakers for a while now and with fathers day comming up my wife gave me a early gift ... I can build new speakers

I then set out to find something new that would wow me. After speaking with Al for a good hour on the phone and countless e-mails (how does he ever get any work done

) I decided to go with the RA8. Part because they should sound fantastic ... part because my wife approves and likes the way they look (as long as the finish is "shiny" she says)

So what am I building ... a total of three RA-8's for the LCR ... I have a front projection system so the center will fit nicely there.

Ok then on to the show .... with the decision in hand to build the the speakers and realizing my helpers would rather run away with the glue bottle rather than giving it to me

I then decided to let the fine folks at Windor Plywood help me cut the wood up. With their tools and help we got the entire amount cut and done in 45 minutes .. only takes 3 sheets of MDF (less than one per speaker).

Here is 3 speakers worth of wood

The first thing I did was to draw out a brace ... I know it doesn't need to be perfect and they are not ... I used a table saw to cut the straight parts of the U and a jig saw for the circle ...

Any just like that they were done ... only took me maybe 90 minutes ...

And to end out day one I drew out the fronts for the RA8

That way I could be sure when day two rolled around I could do some router work

Sure enought day two came and I broke out the router ... first things first I build a circle jig ... simply a piece of 1/4 plywood ...

Cheep easy and works as good as anything ...

Then I went to town ....

And there we are ... I have all the holes for the m-130's done .. I also did round over the back last night but forgot to take a pic .. I'll do so tonight ...

Well thats all for now ... Tonight I hope to do the tweets, ports and terminal cups ...

With any luck I'll have them RTA by this weekend .... I'm still waiting for my kits but Al tells me they will ship today or monday.

More to follow ....

Ted

klh · « **Reply #1 on:** 28 Apr 2006, 07:58 pm »

Damn! You don't wast any time. Can't wait to see the finished product. What are you going to do for surrounds?

Tedp · « **Reply #2 on:** 28 Apr 2006, 09:08 pm »

Use what I got for now ... later build something from Al that uses the same basic drivers to sound the same ...

Ted

Berndt · « **Reply #3 on:** 28 Apr 2006, 10:08 pm »

Nice!
Just bought my kit yesterday.
This is fun.

Tedp · « **Reply #4 on:** 30 Apr 2006, 07:21 pm »

PArt II

I got a little further today. I routed the tweeter and terminal cup holes (they take the same size hole) I also drilled the 2" holes with a hole saw and a drill press ....

Here is a pic of the center completed back

And then I put toghether the center sides, front, top and bottom ... I used brads and wood glue with clamps to ensure a tight fit.

With any luck I'll get the rest of this speaker done today and start on the mains ... just to give a little prespective on how big these speakers are here is me (6'3") standing next to one.

Not the best pic but it will have to work.

Anyways I'll put more up as I have it.

Ted

machine · « **Reply #5 on:** 1 May 2006, 02:45 am »

Yer gonna love these!

Milehighguy · « **Reply #6 on:** 1 May 2006, 06:06 am »

You certainly are making fast progress, but I noticed something...

On my pair (made by Al) there is more space from the bottom of the cabinet to the bottom speaker than there is from the top of the cabinet to the top speaker.

Specifically, there is about 14" from the bottom to the center of the lowest speaker, and there is about 3 and 5/8 inches from the top of the cabinet to the center of the top speaker. This puts the center of the ribbon tweeter at about 38" from the bottom and about 27" from the top of the baffle board.

This puts the ribbon at about ear level for me when I'm sitting down. I'm an average height man (5'10''). For a taller person such as yourself, I would think that it would be even more of an issue to not have the tweeter too low, in terms of getting in the sweet spot or area of best vertical dispersion.

Looking at your picture, it appears that you have equal space between the top woofer and the top of the baffle board and the bottom speaker and the bottom of the baffle board, which moves the center of the ribbon down to probably about 32 or 33 inches from the bottom of the baffle board.

The tweeters do have better than average vertical dispersion, but you still don't want to create a problem by mounting the tweeter too low. I would also think that, when seated, having your ears as close as possible to the midway point between the midranges is also the best idea.

At this point, I would think you could build a stand to elevate the speakers, or figure a way to tilt them a little, or start over, or ignore this post and hope for the best.

Best of luck. They are exceptional speakers.

Tedp · « **Reply #7 on:** 1 May 2006, 06:19 am »

Hehe .. that is because my speaker you are seeing is a center ... I have three of these puppies comming

.. the others are exacally as you describe ...

Ted

Milehighguy · « **Reply #8 on:** 1 May 2006, 06:43 am »

Great! that's a relief because I hate to be the bearer of bad news!

You really are going to love the speakers when they're done.

Tedp · « **Reply #9 on:** 5 May 2006, 04:38 pm »

Well I have the raw boxes pretty much done; three just like this

I also received my kits yesterday

Man three RA8 kits take up a lot of space ... Al had to ship them in two boxes (good size ones at that) here are a few pics of the kits

First they take up an entire table top

Man this is the first time I got to see a M130 driver they are actually very nice

This speaker also sports one heck of a nice terminal cup ... some times it is easy to ruin the look of a very nice speaker with some crappy terminals

Even the crossover parts are very nice ... Hey Al I asked for the non-premium crossovers

these regular crossovers have Sonicaps ... Foil inductors. There is nothing cheap about them at all

man am I glad I did not go for the upgrade ....

And finally the veneer ... I purchased three 4x8 sheets off of him. Al told me he spent 2 hours making sure they matched and even had some figure in them (this is regular straight grain cherry veneer). Who else gives you that kind of service

I did leave it rolled up .. I'll take another pic after I am ready for veneer.

Well thats all folks .. I'll post more as I get more done ....

Ted

klh · « **Reply #10 on:** 5 May 2006, 04:42 pm »

Keep 'em coming!

Berndt · « **Reply #11 on:** 5 May 2006, 07:36 pm »

I just finished my xo's.
I was somewhat daunted, Al sent me some pics and I was able to crack them out.
It is a big kit, at least when you first open the box and start scattering parts all over.
Thanks for all the hand holding Al

Bill

Tedp · « **Reply #12 on:** 6 May 2006, 03:10 pm »

Yeah they are a big kit, I know what you mean. I have one of the boxes veneered not (pic to follow later) and hope to build the crossovers later today .. I think he has sent me the same pics ....

Ted

RAW · « **Reply #13 on:** 6 May 2006, 03:46 pm »

Guy's the crossovers are very very easy.
5 components in the tweeter network
3 components in the mid
1 in the woofer.

Were the HT8
7 in the tweeter
6 in the mid
1 in the woofer.

Sounds like Bill may have his going very soon with some help.
Have to post some pictures when your done Bill.

Ted
Yes a lot of time we spend to sheet match veneer this will come out in our finished product as well as yours.

Matching sheets is not needed but we feel to have a look that must be done is a matched pair.
And when doing large cabinets like the RA8,HT8 or Apex II .
This is very important to us.

Keep the photos coming Ted doing a good job and I think you have the just of it.

Well starting ironing yet??

Tedp · « **Reply #14 on:** 8 May 2006, 04:31 pm »

Ok nolw on to my favorite topiv ... veneering

. I've never been good at veneering ... getting better but still not by any chance perfect ... thought I would give the heat lock glue a try. It works pretty good ... not perfect but better than any thing to date ....

First apply a layer of glue to each surface and let it dry

I glued up the entire veneer sheet (per Al's instructions) ... then cut out the pieces I needed.

Here is a wrap

Oppse is he helping ?

Here are a few completed pics

Not much more to say ... I've also been working on the crossovers (pics to follow). I hope to have them completed tomorrow ...

Ted

Tedp · « **Reply #15 on:** 10 May 2006, 03:41 pm »

Oh I finished the crossover today

Any yes I took this pic before I added resistors to the tweet network.

I also managed to the the two towers finished last night ... It was kinda funny, after just one night of listening (with out a matching center) my wife knew right away I was done ... I tested the old speakers for about 15 minutes just to get a last feel for the sound on a few passages then changed them ... about 30 seconds after I changed them I had my wife poking down stairs asking me if they have been changes ... "really different" was her words

They sound very good ... Now I need to get the center going tonight to see exactly how good the total soundstage sounds

I will post more tonight after hte center is done (I'll also try to remember to get a pic of the gus as I complete it.

Now I also have not yet gotten the finish done. I ordered a HVLP gun to shoot lacquer but won;t get it for a month or so ... in addition to that I'm going to shoot it out side (Lacquer fumes smell sooooo good, but I like my brain) so I'll wait until a nice still day in mid July.

Ted

Tedp · « **Reply #16 on:** 11 May 2006, 08:04 pm »

Ok I got the center done last night (sorry no pics here ... I'm sure I will find some tonight)

Anyways ... amazing is what I have to describe the sound ... clear is another ... speech has always been "hard to hear" unless I turn up the calibration on the center way to high ... of course that lead to other problems .... I have also never had a properly matching front stage ... now all I can say is wow ... speech is clear and there ... I can hear everything I'm supposed to ... both in movies and TV. Also I was playing with things last night and went outside ... I had not realized I turned it up that loud .. I could hear it clearly to the garage ... hmm .. always in the past if I turned it up louder it would hurt the ears before I got to loud ... not this time ...

I put on short passages from the following movies

Black hawk down .... very very good .. could hear the bullets and still hear people talking ... in the past that has been hard ..

Resident evil 2 .. say what you will about the movie the sound is fantastic ...

Star Wars 3 - opening scene .. wow things were buzzing around me every which way

War of the worlds - scene where the tripods first emerge ... again wow

Also it was amazing how the speakers melded ... it really was one very big speaker across the front ... nothing else to say ....

Well I'll let things break in for a while before doing a better demo .. I've also got some new electronics coming in a week or so ( the UL's from Mark Schiffler .... I'm in the first shipment ). I'm looking forward to seeing what those electronics do for these speakers....

Feel free to ask any questions you may have.

Ted

Berndt · « **Reply #17 on:** 11 May 2006, 08:56 pm »

congrats ted
Looks good! Am glad to hear your results are so promising.
Still haven't been able to slot my cabinets in with my cabinet maker friend.
I am envious.

mumbles · « **Reply #18 on:** 12 May 2006, 08:11 pm »

Thanks for the pictures
Ted your speakers look really good. I also feel a lot better seeing someone else with a big center. I am working on the ApexC and have had moments of wondering if I had over done it. Your enthusiasm has inspired me to make some real progress this weekend. More pictures would be great.

Mumbles in Toronto

Berndt · « **Reply #19 on:** 13 May 2006, 03:55 pm »

Ted, I am curious about the acoustic treatments that you applied to the interior of the cabinets.
What did you use?
Any pics of that ?
Thanks, Bill