Basically I used a big wool baffle as in the picture in this post. Later in this post I did a wood baffle of the same dimensions.
The wood baffle measures as predicted from the Edge, big gain in low frequencies but the response goes nuts as predicted in the Edge so isn't usable full range in any shape or form. If we use the wool baffle instead we get withing 1 dB error the same low frequency gain but none of the dipole peak issues as I show in a combined picture in this post.
My theory is that we can think of the sound as water, with a solid baffle the water falls off the sides creating a waterfall at the edges. This means that all water passes exactly around the edge which creates the big anomalies in the repsonse.
Based on my observation i'd assume that the sound just wants to travel the cheapest way to the other side. Because the whole baffle is lossy we can think of it as a filter: some sound will pass everywhere but if sound has already saturated an area it is cheaper to find a new area of the baffle not yet saturated. In the end there is no single point where all sound passes and thus the dipole peak is spread over the whole range, thus disappearing.
If we continue the discussion we should probably jump to that thread / start a new one on the topic so we don't derail this topic more than we already have =)
These may not qualify as dipoles above 800 hz, but they are razor sharp AND nicely ambient, 12 " horns, selenium mids,
Fane tweeters, and Celestion 15 " woofers.
Again, actively crossed over and triamped.
It's wonderful to not need to build new crossovers for each design.
Horns're 105db/watt, woofers come in at 98db/watt, and sound very natural on vocals.
Simple 19mm Cabernet stained linseed oil, 54x24", same ratio as 2001 space monolith (1-4-9) lol!
Fane tweeters, and Celestion 15 " woofers.
Again, actively crossed over and triamped.
It's wonderful to not need to build new crossovers for each design.
Horns're 105db/watt, woofers come in at 98db/watt, and sound very natural on vocals.
Simple 19mm Cabernet stained linseed oil, 54x24", same ratio as 2001 space monolith (1-4-9) lol!
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A paper cone tweeter would be a better match with the seas TV21 (had those many moons ago) You could pare the ribbons with them and this way use the ribbons in the area where they really shine, above 10 kHz. Many paper cone tweeters are very good in the lower region but are worse above 10-13 kHz or so. Have done this pairing with a ribbon for years with very good succes.
In the photo of post# 1288, are there 2 waveguides as I see it?
So you use one of them with HF driver and the other with mid driver?
Nice looking OB. They design 2 woofer in parallel so the low driver is 4 Omh and the fullrange is 8 ohm. is it right?
Any pictures? I have one nos pair left; looking for one more project for them.
Contemplating some kind of Stig Carlsson / dipole hybrid, with a sub handling deep bass.
No problem. You just have to make 8 ohm high pass and 4 ohm lowpass passive crossover.
I did an pop box clone / omni with spherical enclosure surrounded by 4 cone tweeters and compared it to a dipole... the dipole sounded much better so I scrapped the omni =)
But yeah, cone tweeters are awesome!
They behave kinda like a dome tweeter but with a small waveguide, they are not as omni as a dome so they are easier to integrate.
In my speaker (which soon should be finished) is a small cone tweeter in front of my 6.5" midrange to make it into a DIY coaxial, the directivity of the cone tweeter meshes well with the top end of the mid so it was easy to fix the crossover.
That measurement is before I went active on the mid / tweet so the final version measures slightly better but I seem to have lost those measurements. It wasn't a big difference, the major difference is rather the reduced power handling on the tweeter =)
EDIT: Found a picture of the now demolished (I think) omni speaker.
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It isn't in that version but it is planned to mount a big wool baffle in front of the drivers =) That mainly smoothes out the midrange response though and doesn't do as much for the 10" driver. So yeah, I'm not getting much bass from that 10" but on the bottom of the speaker (not visible in picture) there is a W-frame with 2 10" high excursion subs that handles the bass up to about 100 hz =)
There has been some projects here that has used pendulum arrangements, and apparently the point is that while it will swing a bit the resonance of the swing is so low it practically doesn't exist. We are talking about 1 hz or something which is nowhere near where the drivers operate.
There has been some projects here that has used pendulum arrangements, and apparently the point is that while it will swing a bit the resonance of the swing is so low it practically doesn't exist. We are talking about 1 hz or something which is nowhere near where the drivers operate.
Okay, I lied.
THIS is as open as I can make the tv21's.
Seas got a lot right back 30 odd years ago, sounds much better than expected with backup from a 15" woofer on an open baffle for sub 200 hz.
I will experiment with some cardboard wings this weekend, or some carpeting scraps if a store has some.
Now I wonder if some open cell foam might be appropriate too.
THIS is as open as I can make the tv21's.
Seas got a lot right back 30 odd years ago, sounds much better than expected with backup from a 15" woofer on an open baffle for sub 200 hz.
I will experiment with some cardboard wings this weekend, or some carpeting scraps if a store has some.
Now I wonder if some open cell foam might be appropriate too.
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Ugliest open speaker?
Two concerns- slight upper mid tilt , worked around by dropping the tweeter crossover to the minimum recommended 2000 hz point, and a 6watt power rating on these hard to find TV 21's.
Just for laughs, hooked up some old NOS M&K /Peerless 5 1/4's in series with 2 paralleled Seas.
The voice coils inductance smooths things enough to move my tweeters crossover up to 3000 hz, a full thousand hz above minimum recommended point.
Pretty much the last bit of "nasality" is gone from solo vocals now, power handling is doubled , 8.72 Re allows the fewer windings of an 8 ohm tap on the mids amp,this crazy idea works well! They're voiced well enough now to use with no eq'ing, a bonus.
And yes, I know they ARE ugly; but they have great personality when bass is provided by one of the speakers from post 1288.
Two concerns- slight upper mid tilt , worked around by dropping the tweeter crossover to the minimum recommended 2000 hz point, and a 6watt power rating on these hard to find TV 21's.
Just for laughs, hooked up some old NOS M&K /Peerless 5 1/4's in series with 2 paralleled Seas.
The voice coils inductance smooths things enough to move my tweeters crossover up to 3000 hz, a full thousand hz above minimum recommended point.
Pretty much the last bit of "nasality" is gone from solo vocals now, power handling is doubled , 8.72 Re allows the fewer windings of an 8 ohm tap on the mids amp,this crazy idea works well! They're voiced well enough now to use with no eq'ing, a bonus.
And yes, I know they ARE ugly; but they have great personality when bass is provided by one of the speakers from post 1288.
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MITsound,
Which 21TV model do you have?
Are they simply 21TV? 21TV-G, 21TV-GW?
4ohm / 8ohm?
4ohm G has 8w power handling. Does it mean that it would be 16w for the 8ohm version?
21TV-GW has a much bigger magnet; does it mean that it can handle more power?
I have Gs and GWs waiting to be utilised in a OB or cardioid.
Which 21TV model do you have?
Are they simply 21TV? 21TV-G, 21TV-GW?
4ohm / 8ohm?
4ohm G has 8w power handling. Does it mean that it would be 16w for the 8ohm version?
21TV-GW has a much bigger magnet; does it mean that it can handle more power?
I have Gs and GWs waiting to be utilised in a OB or cardioid.
They play no louder than with a single driver going; this may mean some additional phase cancellation is happening, or the 9 db less efficient M&K drags the average down.
I like the tilt; my reasoning is it results in a passive low pass- the cone breakup should theoretically be directional enough to "beam" over the listener's ears, and therefore be inaudible.
They were listed on eBay as Nos, new in box Tv21's, and have no markings on them. They measure 3.5ohms each with a multi meter.
If yours handle 8 watts each, yes they should handle 16 watts each in parallel.
Have fun with these. They are far better than I ever expected.