Hello,
I've just inherited these ~70s speakers; they sound dreadful. However I really like the solid wood cabinets.
I'm completely new to diy speakers but I'm comfortable with electronics so I'll want to mess around with these some more later but for now I'd just like to get them playing decently.
A lot of you guys recommend building a proven design first but I haven't been able to find one that's particularly similar.
The closest I've found in size is this one: http://www.troelsgravesen.dk/STUDIO-101-mkII.htm but the design is very different or this one https://sites.google.com/site/undefinition/bookshelf-speakers/virage but the sizes are also quite different.
So right now, I'm thinking of looking for a 7/8" and a 1" dome tweeter similar to the builds above.
Has anyone else retro-fitted a cabinet?
What are the big things that I need to consider?
Inside dimensions: 55cm x 26cm x 21cm (to the bottom of the mounting board) HxWxD ~ 30 litres
Height available to mount speakers is around 41cm, inside is completely empty.
I've just inherited these ~70s speakers; they sound dreadful. However I really like the solid wood cabinets.
I'm completely new to diy speakers but I'm comfortable with electronics so I'll want to mess around with these some more later but for now I'd just like to get them playing decently.
A lot of you guys recommend building a proven design first but I haven't been able to find one that's particularly similar.
The closest I've found in size is this one: http://www.troelsgravesen.dk/STUDIO-101-mkII.htm but the design is very different or this one https://sites.google.com/site/undefinition/bookshelf-speakers/virage but the sizes are also quite different.
So right now, I'm thinking of looking for a 7/8" and a 1" dome tweeter similar to the builds above.
Has anyone else retro-fitted a cabinet?
What are the big things that I need to consider?
Inside dimensions: 55cm x 26cm x 21cm (to the bottom of the mounting board) HxWxD ~ 30 litres
Height available to mount speakers is around 41cm, inside is completely empty.
Hey
I do like those cabinets. Id ditch the driver, it looks like a 6x9 for a automotive application. Maybe remove that baffle and place a single full range there? Not sure.
What’s the dimensions on the cabinets?
I’m curious how this develops. Lot to be said for a proven design though
Hmmm
Was just looking again, what’s with that switch? Those cabinets look decent sized, maybe a two way add some bracing and dampening. Hey, go active!
Oops, I’m otta control
The Carmody design gets my vote
I do like those cabinets. Id ditch the driver, it looks like a 6x9 for a automotive application. Maybe remove that baffle and place a single full range there? Not sure.
What’s the dimensions on the cabinets?
I’m curious how this develops. Lot to be said for a proven design though
Hmmm
Was just looking again, what’s with that switch? Those cabinets look decent sized, maybe a two way add some bracing and dampening. Hey, go active!
Oops, I’m otta control
The Carmody design gets my vote
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There's quite a gap between what a 7-8" woofer and a 1" tweeter can handle frequency wise, you may be better with the woofer plus a 3" full range driver. If there's space, you can even go for a 10" woofer in that configuration, but baffle size and volume may prevent this.
I'm no speaker building expert, hopefully other, wiser heads will be along to comment soon - have fun!
I'm no speaker building expert, hopefully other, wiser heads will be along to comment soon - have fun!
The internal cabinet volume and the port geometry/tuning frequency are the most important parts of this. Minor differences in overall cabinet dimensions are going to make minor differences in sound. If one is a little taller, narrower, etc. I wouldn't worry much as long as the internal volume is within about 10% of that of the original design. Ports can typically be moved without a large impact also. Some are obsessed with modeling all aspects of a design, but given where the speakers are coming from and your stated goals, I'd ignore some smaller differences.
Another important thing is the driver alignment in the Troels design (the step in the baffle and the physical driver alignment in all 3 dimensions). That needs to be the same as designed for the crossover region to integrate properly. Same idea with a design that uses a flat baffle - you don't want to change driver alignment, however it's done.
If money is no object, the Purifi drivers are nice, but if you really just want to "get them playing decently," they may be overkill.
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I am a big advocate of WAWs :^) A 100mm PVC tube out the back.
But if you want simple, really good on a budget, a pair of CHN-110, will work sealed but probably adding a vent (75mm D x 440mm or 50mm D x 180mm), a really good FR, astonding value for the £, only 1 driver to fit into a new baffle (just put it over the existing one), no XO to muck with (or to muck with the sonics). The box coulkd probably do with some bracing before you attach the new baffle, port dimensions might need a bit of tweaking for the reduced volume.
https://kjfaudio.com/product/chn-110/
One World • One • Pure Music
dave
Note cheap — Twice. And without the tweeter and XO twice the cost of the Markaudio driver. Not cheap. https://www.bluearan.co.uk/index.ph...=Co-axial_Speakers&subheadnew=_8_inch_Coaxial
But nothing wrong with the idea. There is a long coax thread going, you can look at teh pros and cons. https://www.diyaudio.com/community/threads/why-dont-people-build-more-coaxial-systems.397889/
dave
Quite a nice find of a cabinet. I remember a 2 way project from one of the German diy magazines
presenting a classic 2 way, woofer being an 8" unit. Can't remember the mag issue and should I
dare find the one, it'll take some time.
presenting a classic 2 way, woofer being an 8" unit. Can't remember the mag issue and should I
dare find the one, it'll take some time.
How about this one:
http://woggmusic.com/supernova-minimus-speaker-build/
A refit of an old cabinet, with similar dimensions to yours: 48x27x18 cm (external). The design uses an Dayton RS180P (6.5") woofer and Vifa tweeter. It scored quite well in a speaker design competition; the crossover only has five parts so an easy build. You would need a new baffle, of course but it looks like you could inset that into the front..
Geoff
http://woggmusic.com/supernova-minimus-speaker-build/
A refit of an old cabinet, with similar dimensions to yours: 48x27x18 cm (external). The design uses an Dayton RS180P (6.5") woofer and Vifa tweeter. It scored quite well in a speaker design competition; the crossover only has five parts so an easy build. You would need a new baffle, of course but it looks like you could inset that into the front..
Geoff
Thanks everyone!
The switch thing is just a connector since the original one at the back was mangled.
Yeah the drivers are definitely going, the surround has detached.
The switch thing is just a connector since the original one at the back was mangled.
Oh wow, can't believe you found the original ad! Its not vented at all the black mdf board goes all the way to every side; the box just has some padding sort of thrown in but otherwise is completely empty.
Good to know the 10% figure and the drive placement is key; should narrow down the list 👍
That one looks pretty similar, the volume is still quite a bit smaller - 23L vs 30L; but I guess I can add some boards inside top and bottom to effectively reduce the height of mine from 55cm to around 45cm.
If your looking for a 8" speaker for a 30 liter box
Then Dayton DA215-8 is perfect match
has low Fs for price range 34 Hz
good sound and flat response with aluminum cone.
Standard vented QB3 alignment
Is 29 liters tuned 35 to 37 Hz
Cabinet loaded with speakers, the magnets, port and other mounted
items like crossover will displace likely one liter.
So is dead match for cabinet.
8" speaker requires low crossover point for tweeter.
Close to 1200 to 1400 Hz for ideal off axis response.
And also needs close mounting to woofer. Or very
close center to center spacing.
This requires a Tweeter with very low Fs
so it has low distortion crossed over so low.
Around 700 to 800 Hz
The solution is another Aluminum Dayton Driver
RST28A-4
I would use truncated faceplate/ mounting bezel so it can be mounted
close to woofer as possible.
This is 1" 1/8 tweeter Fs is 775 Hz so is suitable to cross low
to a 8" driver.
Then Dayton DA215-8 is perfect match
has low Fs for price range 34 Hz
good sound and flat response with aluminum cone.
Standard vented QB3 alignment
Is 29 liters tuned 35 to 37 Hz
Cabinet loaded with speakers, the magnets, port and other mounted
items like crossover will displace likely one liter.
So is dead match for cabinet.
8" speaker requires low crossover point for tweeter.
Close to 1200 to 1400 Hz for ideal off axis response.
And also needs close mounting to woofer. Or very
close center to center spacing.
This requires a Tweeter with very low Fs
so it has low distortion crossed over so low.
Around 700 to 800 Hz
The solution is another Aluminum Dayton Driver
RST28A-4
I would use truncated faceplate/ mounting bezel so it can be mounted
close to woofer as possible.
This is 1" 1/8 tweeter Fs is 775 Hz so is suitable to cross low
to a 8" driver.
Interesting speakers. I remember the cheap 13"x9" drivers from the 1960s, made by EMI and featuring a choice of either 1 or 2 tweeters and crude crossover. Peter Baxandall used something very similar in this design:
https://keith-snook.info/wireless-w...ld-1968/Low-cost High-quality Loudspeaker.pdf
He even compared them against Quad ESL (57s)!
Use of elliptical cones has advantages in terms of better control of break-up. I suspect the main reason they're not more popular is to do with aesthetics. Though Mordaunt Short for one has used them (in much higher quality drivers, it should be said)...
https://keith-snook.info/wireless-w...ld-1968/Low-cost High-quality Loudspeaker.pdf
He even compared them against Quad ESL (57s)!
Use of elliptical cones has advantages in terms of better control of break-up. I suspect the main reason they're not more popular is to do with aesthetics. Though Mordaunt Short for one has used them (in much higher quality drivers, it should be said)...
These were a quite decent Isophon coax. 12x7.
I have 2, unfortunetly one is 4Ω the other 8Ω
dave
I have 2, unfortunetly one is 4Ω the other 8Ω
dave