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Multi-Way Conventional loudspeakers with crossovers

Need Help: Designing 12" Tannoy + 15" Woof
Need Help: Designing 12" Tannoy + 15" Woof
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Old 30th October 2019, 07:21 AM   #21
KrautNotRice is offline KrautNotRice  United States
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Originally Posted by Zvu View Post
The point is that you will not need full baffle step since there will be lots of boundary reinforcement. That means that you can get by with a woofer that doesn't have to be 4-6dB more sensitive than midrange.
You mean down firing is easier?

I think a big impact on price of passive will be whether the mid has to be high-passed, or can get away without high-pass bc it would be mounted in a small sealed space. If it needed to be high-passed, we're talking about a very expensive set of caps at the least, plus another set of big inductors.
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Old 30th October 2019, 07:51 AM   #22
Zvu is offline Zvu  Serbia
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Not necessarily down firing but in close proximity to the floor. Since you can't escape that surface, you just might use it to boost the low frequencies and use lesser baffle step compensation (in some cases none).
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Old 30th October 2019, 08:50 AM   #23
Zvu is offline Zvu  Serbia
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Here it is.

Дејтон ПА380-8.png

ERSE - Super Q
ERSE - IXQ Coil

330uF 100V Electrolytic Non-Polarized Crossover Capacitor
200uF 100V Electrolytic Non-Polarized Crossover Capacitor
50uF 100V Electrolytic Non-Polarized Crossover Capacitor

https://www.parts-express.com/dayton...esistor--004-7
https://www.parts-express.com/22-ohm...erance--016-22

R1 is 3 x 22 ohm resistors in parallel, C2 is 330uF+50uF.

Crossover point would be around 150Hz. It's 6dB/o slope at crossover frequency and after 300Hz there is a steeper slope for less interaction with midrange - elliptical filter. 6dB/o acoustical slope at crossover frequency so there shouldn't be any bad interaction or dip forming due to low phase shift. Erse coils are quite amazing actually so no harm in using them.

https://www.youtube.com/watch?v=sxJBK4JIYJk

I'd definitely mount the woofer bellow the Tannoy DC on the front baffle - but that's just me. Simulation is given for Dayton Audio PA380-8 in a 100 liter cabinet with tuning frequency at 40Hz.Purple line is without crossover and bordeaux is with crossover in place.
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Last edited by Zvu; 30th October 2019 at 08:58 AM.
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Old 30th October 2019, 06:17 PM   #24
KrautNotRice is offline KrautNotRice  United States
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Quote:
Originally Posted by Zvu View Post
Here it is.

Attachment 791141

ERSE - Super Q
ERSE - IXQ Coil

330uF 100V Electrolytic Non-Polarized Crossover Capacitor
200uF 100V Electrolytic Non-Polarized Crossover Capacitor
50uF 100V Electrolytic Non-Polarized Crossover Capacitor

https://www.parts-express.com/dayton...esistor--004-7
https://www.parts-express.com/22-ohm...erance--016-22

R1 is 3 x 22 ohm resistors in parallel, C2 is 330uF+50uF.

Crossover point would be around 150Hz. It's 6dB/o slope at crossover frequency and after 300Hz there is a steeper slope for less interaction with midrange - elliptical filter. 6dB/o acoustical slope at crossover frequency so there shouldn't be any bad interaction or dip forming due to low phase shift. Erse coils are quite amazing actually so no harm in using them.

https://www.youtube.com/watch?v=sxJBK4JIYJk

I'd definitely mount the woofer bellow the Tannoy DC on the front baffle - but that's just me. Simulation is given for Dayton Audio PA380-8 in a 100 liter cabinet with tuning frequency at 40Hz.Purple line is without crossover and bordeaux is with crossover in place.
Wow, thank you for doing that!
Looks like a quite complex crossover, as predicted. The cost of the parts would probably be more than a pair of plate amps...
Planet, why didn't you say so? lol jk
I think my next step is to try and get the Tannoys sounding good on their own, to see if they're worthy of the investment.
The supplied crossover is loud, but all midrange and it doesn't sound balanced at all. For starters, I may try an l-pad on the tweeters to dial them down, but I'm afraid even then they will still be too middy. Maybe they need a higher xo point...
I've got a lot of caps, resistors and coils around to play with.
Will keep updating this thread.
Also, if anyone has any suggestions as to a simple way to shelf the mids in a simple 2 way (both 2nd order) that could point me in the right direction.
Thank you!
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Old 30th October 2019, 07:01 PM   #25
planet10 is offline planet10  Canada
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Need Help: Designing 12" Tannoy + 15" Woof
Thanx Zvu, that clears up the low pass (2 big chokes & a big cap) + the elliptical bits. What about the High Pass? It is unlikely that a sealed box will provide a roll-off that high. The HP should have a cap instead of the 1st inductor, but the resonance trap wil be similar (ie 2 more big caps and another big choke. And i would not use electolytics. Even cheap poly caps are near beer can size — we did a similar XO (at 250 Hz, ie near an octave higher, helf the parts size), and the parts are big.

I figure the point were active starts to cost less than passive is typically around 200-300 Hz.

dave
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Old 30th October 2019, 07:04 PM   #26
KrautNotRice is offline KrautNotRice  United States
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Quote:
Originally Posted by planet10 View Post
I figure the point were active starts to cost less than passive is typically around 200-300 Hz.

dave
I see that now lol
Good rule of thumb.
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Old 18th November 2019, 06:11 PM   #27
lousymusician is offline lousymusician  United States
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KnR,

Any updates on this build?

I bit the bullet and ordered a pair of these drivers yesterday, after having heard 4-per-side arrays of Tannoy ceiling drivers at Burning Amp. Naturally, after I placed the order I noticed something in one of your previous posts:
PA speakers for home HiFi use

"The top end rolls off starting at 10k, with its (smooth) 1.34" aluminum dome with bullet phase plug (not tulip)." (emphasis mine)

OK, as far as I can tell that makes this a whole different class of Tannoy DC driver. I only know three tweeter variants: the original pepperpot drivers ($$$ these days), the tulips (which I heard at BA), and the new Omnimagnet design used in the Revolution series and the CMS 803/603/503 ceiling speakers. The Omnimagnet tweeters have a bullet (ogive) phase plug and an annular plastic diaphragm, and use a common magnet structure with the woofer. The CMS 1201 tweeter has an aluminum diaphragm and a Neo magnet that is not shared with the woofer (like a tulip), but according to your observation has an ogive phase plug. Some kind of hybrid or intermediate design? Or have I missed other drivers like this? I wonder if the diaphragm is actually a full dome, or a ring radiator? And whether this is an improvement, or a cost cutting measure? Tannoy do not appear to have published details of this new tweeter arrangement.

I have some suitable test boxes standing by in the garage, and reasonable measurement gear (Omnimic, REW, S&L Woofer Tester II), so I'll work on getting the best set of measurements I can in my small listening room once the drivers arrive. The published FR curve indicates (to my eye at least) that some work may be needed to flatten the response around the xover for hifi use:

https://media63.music-group.com/medi...20Document.pdf

Bill
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Old 18th November 2019, 06:27 PM   #28
KrautNotRice is offline KrautNotRice  United States
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Quote:
Originally Posted by lousymusician View Post
KnR,

Any updates on this build?


Bill
Hi Bill,
Yes lots of updates. At first I had them mounted in my test cabs that had holes in it on front and back, so there was little deep bass.
The tweeters seemed to roll off pretty much at 10k, but once I let the speakers play for over a week straight, then listened to them again critically, the tweeters had totally OPENED up and now play as high as they're supposed to.
From what I can tell they're actually 1.34" aluminum domes, not ring radiators, but I could be wrong. I've had them apart when removing the crossover bracket from the woofer basket.
Initially I didn't know the tweeter would come apart on me when removing the tweeter's mounting bolts to remove the large crossover bracket from the woofer basket. It came apart on me and luckily I didn't break anything, I put it back together and centered the tweeter voice coil in its magnet gap as good as I could.

Next phase was properly porting the test cabs. They're 48 liters, I ported them to 53 hz using three 2" ports cut to length, mounted with hot glue on a removable baffle that is screwed on. This really improved the bass response, but it wasn't until I added 6db of baffle step correction that the speakers really came into balance.
No surprise of course. The stock xo doesn't have any bsc because they're ceiling speakers, so the entire ceiling is their baffle.

At this point they sound really awesome, much better than at first, the break in did magic for the tweeters. I also played a 30 hz since wave for 10 hours to break in the woofers, but I have a feeling they've still got a while to go. I only had a mini amp on hand, so I doubt I was feeding the woofers more than 10 watts.

More to come, but so far I'm very happy with how they sound after initial break in and porting to 53 hz plus bsc.

fullsizeoutput_8e0.jpg

fullsizeoutput_8df.jpg

fullsizeoutput_8de.jpg

Last edited by KrautNotRice; 18th November 2019 at 06:39 PM.
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Old 18th November 2019, 06:32 PM   #29
KrautNotRice is offline KrautNotRice  United States
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Quote:
Originally Posted by lousymusician View Post
KnR,

Any updates on this build?

Bill
And yes, the phase plug is more like a bullet shape. My previous 8" DCs were tulips, I've also got some pepperpots on hand (SRM12B), and these 1201 DC are definitely not omni magnets.
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Old 19th November 2019, 12:01 AM   #30
lousymusician is offline lousymusician  United States
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Cool, thanks for the update. I'm sure that you would know if the diaphragm was a ring radiator, there would have been a hole in the middle. I'll have to get a better look at the phase plug once I get mine.

How did you implement the BSC? Any other crossover tweaks?

Bill

Quote:
Originally Posted by KrautNotRice View Post
Hi Bill,
Yes lots of updates. At first I had them mounted in my test cabs that had holes in it on front and back, so there was little deep bass.
The tweeters seemed to roll off pretty much at 10k, but once I let the speakers play for over a week straight, then listened to them again critically, the tweeters had totally OPENED up and now play as high as they're supposed to.
From what I can tell they're actually 1.34" aluminum domes, not ring radiators, but I could be wrong. I've had them apart when removing the crossover bracket from the woofer basket.
Initially I didn't know the tweeter would come apart on me when removing the tweeter's mounting bolts to remove the large crossover bracket from the woofer basket. It came apart on me and luckily I didn't break anything, I put it back together and centered the tweeter voice coil in its magnet gap as good as I could.

Next phase was properly porting the test cabs. They're 48 liters, I ported them to 53 hz using three 2" ports cut to length, mounted with hot glue on a removable baffle that is screwed on. This really improved the bass response, but it wasn't until I added 6db of baffle step correction that the speakers really came into balance.
No surprise of course. The stock xo doesn't have any bsc because they're ceiling speakers, so the entire ceiling is their baffle.

At this point they sound really awesome, much better than at first, the break in did magic for the tweeters. I also played a 30 hz since wave for 10 hours to break in the woofers, but I have a feeling they've still got a while to go. I only had a mini amp on hand, so I doubt I was feeding the woofers more than 10 watts.

More to come, but so far I'm very happy with how they sound after initial break in and porting to 53 hz plus bsc.

Attachment 795886

Attachment 795887

Attachment 795888
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