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Looking for enclosure for Richard Allan Atlas 15

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Jahmateur View Drop Down
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    Posted: 30 August 2017 at 11:12am
Hi there! 

First post ever on speakerplans, and pretty new to sound. Thanks a heap for any replies! 

So I'm building a small, diy reggae sound system. No plans for going big, going for the bestest, crispest sound on the lowest frequencies. I just want to play some loud, fair sounding reggae music. 

Scoops, mid highs and highs are covered for now. But I really lack midlow/kick. 

I have 2 Richard Allan Atlas 15's laying around, and no money, so that's what I want to work with. Not too much information to find on these speakers, but they seem to work well in reflex/ported enclosures.
They are 250 watts a piece, 8ohm. The other specs i found can be seen in this table: http://imgur.com/a/gU4o9

So now my question is. What enclosures do I put these in? I'd love to have a double reflex/ported enclosure with these in it, also for simplicity of build and looks. I cant seem to find any plans for double 15inch. Do I just build a random 6-sided box with ports in it (reggae-style)? Do I need deeply calculated plans? 

Again, thanks a bunch for any insights! Much apreech!
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mini-mad View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 1:45pm
...why not look up car subwoofer plans. Find a box tuned down to 40hz and test one in that. With out to much info on the driver you won't get to far with a driver.

But there are a ton of single and double 15" car sub enclosure designs floating about on Google images and to be honest there nothing clean or crisp about Reggie bass frequencies. Scoops colorize and distort the music so you MAY be better of looking for dirty bass...

If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote DMorison Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 2:19pm
Something about those TS parameters doesn't add up, and there's a couple of important ones missing too, so at present it's hard to be sure of what they'll do.

The missing ones are Re (the DC resistance of the voice coil) - you can measure this yourself with any reasonably accurate multimeter; and Xmax (the maximum distance the cone can move while keeping its behaviour linear, in response to increasing power levels), which unfortunately is hard to measure.

I've had a quick google and found the same table of parameters in a couple of other places, but nothing more. If you can find the missing ones, that'd go a long way to help make any modelling accurate.

The other thing that's odd is the relationship between BL and Qes. For an 8Ω driver, BL would normally be much higher than that if the stated Qes is correct (or Qes lower if BL is correct). The only way those 2 values would be likely to co-exist is if Re is much lower - possibly making it a 2Ω driver, not 8Ω.

(Cms is also off, but that one looks like a simple decimal place shift, it seems to work out well enough if the actual value was 0.102mm/N).

What you'd do is put the parameters into a modelling program like WinISD which will then allow you to see what kind of response shape you'll get in different box sizes, and it'll calculate approximate dimensions for ports too.

Any modelling is only as accurate as the input parameters though, so given my first two points, the following is highly provisional...

I've had a quick play, and the main thing that I can see is that they're not very efficient - approx 93dB for one Watt of power each. This does have a useful side effect, in that they'll go quite deep in very small boxes, however it does limit how loud they'll ever get - 500W into the pair would get them to around 123dB only.

A box size of around 88l for the pair with vents tuned to 46Hz gives flat response to 50Hz, and would need 2 vents each 10cm diameter and 17.9cm long.

Honestly, if you're serious about these keeping up with scoops, I don't think they'll get loud enough, and given they're older drivers there's a real chance you'll end up shredding them if you try to push them.

Have a think about maybe selling them to some vintage hifi enthusiast and using the money to buy something more modern perhaps?



Edited by DMorison - 30 August 2017 at 2:28pm
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Jahmateur View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jahmateur Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 2:39pm
Thanks for the replies! 

Our scoops are '67 JBL scoops or so I've been told, also loaded with vintage Beyma copies and an unmarked driver, so I assume the build you suggest would go good on top of that, at least until we upgrade to 18 inch super scoopers but that'll take a while

Selling these will be hard, and i think it won't give us budget to buy something more modern
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Post Options Post Options   Thanks (1) Thanks(1)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 4:03pm
Those Richard Allan Atlas 15's are true vintage drivers, date from the 1970's ,possibly early 80's. Put them in some Altec 816 style cabinets,that will give you some punch.

https://forum.speakerplans.com/altec-lansing-816a_topic87214.html
Be seeing you.
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Peter Jan View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Peter Jan Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 5:51pm
An educated guess... are you located in Belgium by any chance ?
Back in the day Beyma and Richard Allan was imported by AED over here and I serviced those for many years.
Those Atlas 15 specifically were used in ported 2-way/3-way cabinets.
They did also very well in what was called an "AED bin", which was in fact a copy of the "University Classic horn". Not the most efficient speaker out there, but the horn made up for that. In ported cabs they sound real good well beyond 1 kHz.
Now to use them as lowmid speakers, I would not recommend it even when new, they are not well suited for it as is/was and especially being somewhere between 30 to 45 years old by now. Good quality and fully handmade doesn't change that unfortunately.

If you are located in Belgium, I might hook you up with some modern 15" lowmid speakers to swap for a pair of your Atlas 15 ?






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Jahmateur View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jahmateur Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 6:00pm
Very good guess! Belgium it is! 

I've looked in to sending you a pm, but can't seem to find it. Very interested in a swap! 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jahmateur Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 7:01pm
Originally posted by Peter Jan Peter Jan wrote:

An educated guess... are you located in Belgium by any chance ?
Back in the day Beyma and Richard Allan was imported by AED over here and I serviced those for many years.
Those Atlas 15 specifically were used in ported 2-way/3-way cabinets.
They did also very well in what was called an "AED bin", which was in fact a copy of the "University Classic horn". Not the most efficient speaker out there, but the horn made up for that. In ported cabs they sound real good well beyond 1 kHz.
Now to use them as lowmid speakers, I would not recommend it even when new, they are not well suited for it as is/was and especially being somewhere between 30 to 45 years old by now. Good quality and fully handmade doesn't change that unfortunately.

If you are located in Belgium, I might hook you up with some modern 15" lowmid speakers to swap for a pair of your Atlas 15 ?







I think i've sent you an email ;)
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bob4 View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 7:01pm
you have to have 10 posts to use the pm function ;) 

this again….. LOL

(it's a recurring problem, newcomers never realize they have to make 10 posts before they can use PMs….)
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Jahmateur View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jahmateur Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 7:04pm
So I should flood this with some more posts and then try to contact Peter? :D
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Jahmateur View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jahmateur Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 7:07pm
Interesting thing is I bought speakers loaded with the Allans & Beyma's around Antwerp, might be something you've built
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Peter Jan View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Peter Jan Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2017 at 8:08pm
Originally posted by Jahmateur Jahmateur wrote:

Interesting thing is I bought speakers loaded with the Allans & Beyma's around Antwerp, might be something you've built

Could be... Big smile
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