Hello guys,
I've done a lot of research on the forum and found many great threads around this question, but I still don't have a clear picture.
On my OB (really nude) with waveguided tweeter, I'd like to extend the dipole behaviour to the highs.
Few years ago on a similar setup I had the TPL-150, it was great really, airy, detailed, super sensitive and flexible for xo.
I only remember its vertical size being a little issue, at the time on MTM.
Sold everything when I moved, then restarted from scratch, for 2 years I was happy, I also had many other things to focus on the system.
Few months ago I went with Azura horns and faital CDs (for many reasons like added sensitivity for tube amp, flexibility, smooth dispersion of the JMLC, curiosity, and just beauty of the object).
But the itch is coming back, I need to find out what I'm missing with a real dipole up there in this room that is now much bigger (around 150m3).
So I'd like to test without breaking the bank, before I sell my pair of tw29bnwg and/or pair of Azuras, do you see anything that could fit the need for an acceptable price, like around 400eur for 4 tweeters or 2 AMTs?
I'd like to avoid selling the current ones as I'm sure I will regret for potential future projects, so many times I sold stuff and needed it later.
The TPLs would have the best dipole behavior, but are expensive (only the tpl-200 are available at TLHP).
I need either high sensitivity or good power handling to match current midrange
Small enough to be attached back to back, with or without a baffle (none right now).
Since I'm also planning to try a different mid range, I need some flexibility on the crossover, for probably a 2kHz high pass, active.
I thought about
As always writing this helped me to clean my thoughts, it seems the SB29SDNC is a very good option, price/power/spl/size, except dispersion.
Or do you have any other idea?
Any details I forgot to help you propose something? Thx!
I've done a lot of research on the forum and found many great threads around this question, but I still don't have a clear picture.
On my OB (really nude) with waveguided tweeter, I'd like to extend the dipole behaviour to the highs.
Few years ago on a similar setup I had the TPL-150, it was great really, airy, detailed, super sensitive and flexible for xo.
I only remember its vertical size being a little issue, at the time on MTM.
Sold everything when I moved, then restarted from scratch, for 2 years I was happy, I also had many other things to focus on the system.
Few months ago I went with Azura horns and faital CDs (for many reasons like added sensitivity for tube amp, flexibility, smooth dispersion of the JMLC, curiosity, and just beauty of the object).
But the itch is coming back, I need to find out what I'm missing with a real dipole up there in this room that is now much bigger (around 150m3).
So I'd like to test without breaking the bank, before I sell my pair of tw29bnwg and/or pair of Azuras, do you see anything that could fit the need for an acceptable price, like around 400eur for 4 tweeters or 2 AMTs?
I'd like to avoid selling the current ones as I'm sure I will regret for potential future projects, so many times I sold stuff and needed it later.
The TPLs would have the best dipole behavior, but are expensive (only the tpl-200 are available at TLHP).
I need either high sensitivity or good power handling to match current midrange
Small enough to be attached back to back, with or without a baffle (none right now).
Since I'm also planning to try a different mid range, I need some flexibility on the crossover, for probably a 2kHz high pass, active.
I thought about
- finding a CD that I can open the back, but here I would have a discrepancy between front waveguide and back unguided.
- Seas 27TFFNC or SBacoustics SB21SDCN, just not sure they can accept a low crossover, and seem limited on power.
- smaller AMTs like the TPL-75 (back can be opened too) or SATORI AT60NC (don't know if can be opened), they are not that cheaper, and I might regret getting the big ones.
- or beefier like SBacoustics SB29SDNC, off axis seem a bit ragged, more directive and no idea how it would react in dipole, but it fits other needs https://audioxpress.com/article/tes...pact-neo-cloth-dome-tweeter-from-sb-acoustics
As always writing this helped me to clean my thoughts, it seems the SB29SDNC is a very good option, price/power/spl/size, except dispersion.
Or do you have any other idea?
Any details I forgot to help you propose something? Thx!
Aurum Cantus 2560 AMT. Been around a while, easy dipole, excellent response, the same front & back, good sensitivity, well built ( but better without the thick facia), not too pricey. They sound great in my system. I have 4; won't part with them. Can't cross as low as 2kHz though.
Whats most important in here is the size of your space and I would assume as you’re currently running dipole, you‘ve managed your boundaries accordingly.
Don‘t be overly concerned with a mismatch in the rear radiation pattern. Use the same CD offset above the forward facing with a deep and narrow lens……you just need it to load the diaphragm. Add diffusion behind the speaker……a wall mounted panel or a tall house plant will do the trick. Don’t overthink this…..a low crossed dome or planar in that size space is going to suffer from power compression and pale in comparison to your current CD installation.
Don‘t be overly concerned with a mismatch in the rear radiation pattern. Use the same CD offset above the forward facing with a deep and narrow lens……you just need it to load the diaphragm. Add diffusion behind the speaker……a wall mounted panel or a tall house plant will do the trick. Don’t overthink this…..a low crossed dome or planar in that size space is going to suffer from power compression and pale in comparison to your current CD installation.
Let's not forget the ESS Heil AMT. They just had a sale for the large one - 2 for $500. It looks like it is sold out already. I use mine in an OB arrangement from 2100 hz and up. It's tough to beat a robust big AMT IMHO.
I use the big Heils as well. The sale pricing comes and goes, but shipping to France might be expensive as they are quite heavy. They need some EQ, and the polar pattern gets uneven past 45 degrees off axis, but they are robust, distortion is low and they will play fairly low. I use them to 1500, others have gone a fair bit lower.
The cheapest alternative might be Charlie Laub's technique of using two carefully selected and modified dome tweeters back to back. Search his history to find the details.
Bill
The cheapest alternative might be Charlie Laub's technique of using two carefully selected and modified dome tweeters back to back. Search his history to find the details.
Bill
I would first try a back firing tweeter and horn - as Perry Marshall does in his designs. I can recommend the big ESS Heils as well, cleanest impulse response I have ever measured. Cheap alternative to test are the GRS planars but they have a narrow dip at around 7 kHz - which others have reported to get rid of with a 3D printed "phase plug".
I'm using a pair of this:
https://www.mundorf.com/audio/en/sh...ormer-Dipole----59x258mm----Neodym/?card=1532
Definitely recommended!
https://www.mundorf.com/audio/en/sh...ormer-Dipole----59x258mm----Neodym/?card=1532
Definitely recommended!
In my personal experience & measurements, used as a tweeter >3K, the Autumn Cantus 2560 wins hands down overGRS or BG Neo3. Haven't compared it to Satori BE tweeter in hand, but then I need 2 of those for dipole. I'd expect the tp150 to be better at higher amplitude, not dynamic perhaps, & able to cross lower, but I really don't think there's any dipole tweeter to touch the 2560 for the price -- around USD180 these days.
There is also a "big brother" of the Aurum Cantus AST2560, the AST25120. The diaphragm for both is the same width but is a bit longer in the AST25120. It offers higher voltage sensitivity and can be crossed over a bit lower. I have used both Aurum Cantus AMTs and IMO they are just about on par with the Mundorf units. I remove the mounting plate to make the size of the "flange" as small as possible, and then the response pattern is really nice.
Radian ribbons are small, light and easy to ship to Europe. Check their website for info and price. They are on their second generation of small drivers. 101 db/w/m with waveguide.
Awesome answers thanks!
At first I didn't select the AST2560 because I couldn't find it in Europe, but after more readings it seems the Hardwood am25 is the same.
500 eur for the pair, much better and all your comments are reassuring.
The Mundorf must be great but is too expensive now.
Thought about the Heils too, I almost bought a pair last year during a sale, but shipping killed it.
I was also afraid by their weight, all my drivers are hanging attached in line.
The Radians are more accessible yes, they are on TLHP, but the AST2560/AM25 seems a better fit.
Great to read.
Yes they have space around, usually between 1 and 1.5m from front.
Front wall is covered with diffusors, ceiling too but less effective (https://www.diyaudio.com/community/threads/quikea-diy-sound-diffusers.395917/)
So I think I will try the CD in the back first, I’m sure I can borrow some from a friend.
I must say I've always been intrigued by the back CD on Perry Marshall’s build.
If not convinced I will go with the AST2560.
I also read a lot from you CharlieLaub and your experiements, was curious to test it for myself.
Also eager to find out about your testings on midrange dipole "symmetry".
Side question :
I will need to find two more channels, I can use the sub one for testing but after I have no idea how to.
Already got 2 minidsp in chain and it’s a PITA.
Unless I just wire them in reversed //, but then should I pick a lower sensitivity one, or the exact same CD?
Would it mess up the front CD impedance/response?
At first I didn't select the AST2560 because I couldn't find it in Europe, but after more readings it seems the Hardwood am25 is the same.
500 eur for the pair, much better and all your comments are reassuring.
The Mundorf must be great but is too expensive now.
Or did you mean we can remove the back cover on the regular line?
Thought about the Heils too, I almost bought a pair last year during a sale, but shipping killed it.
I was also afraid by their weight, all my drivers are hanging attached in line.
The Radians are more accessible yes, they are on TLHP, but the AST2560/AM25 seems a better fit.
Great to read.
Yes they have space around, usually between 1 and 1.5m from front.
Front wall is covered with diffusors, ceiling too but less effective (https://www.diyaudio.com/community/threads/quikea-diy-sound-diffusers.395917/)
So I think I will try the CD in the back first, I’m sure I can borrow some from a friend.
I must say I've always been intrigued by the back CD on Perry Marshall’s build.
If not convinced I will go with the AST2560.
I also read a lot from you CharlieLaub and your experiements, was curious to test it for myself.
Also eager to find out about your testings on midrange dipole "symmetry".
Side question :
I will need to find two more channels, I can use the sub one for testing but after I have no idea how to.
Already got 2 minidsp in chain and it’s a PITA.
Unless I just wire them in reversed //, but then should I pick a lower sensitivity one, or the exact same CD?
Would it mess up the front CD impedance/response?
That's a hefty price given it's USD181 at partsexpress! And PE discounts it another $25 if you get a basic OEM account.
It'd simply too anarchic IMO to ***** or fine tune......if it sounds good, it is good. The basket and magnet create such immense diffraction as to make this an exercise in futilty
If the HF is on it's own DSP channel, you could wire them in series reverse polarity and adjust the gain to level match to your mids.
Purists will say that you will need to delay all of your front output channels by accounting for the distance offset......if the throat of the rear firing CD is say 3" aft then you'd need to add a delay of 3.5 milliseconds
I have never meet anyone that can perceive 3.5ms of latency but this is hifi so cumulatively, everything matters.......YMMV
I sure miss my days in US with access to PE, but TLHP is a great alternative, with and a huge collection!
It’s certainly a hard path, I can't see any driver with small enough motor to not mess up the high mids.
Maybe the hunderhung ones can act as side diffusor, when they have the pretty smooth motor shape, acting like a lens.
So no adequate CDs available from friends, two more fatails would come close to the price of the other AMTs so I’m thinking about getting a pair of these for 100eur:
They’re less sensitive but I thought I could just split the HF with a Y rca and drive them with a small but more powerful amp I have around, with volume control.
I could even add an unused analog eq (Schiit Loki) to adjust the response if needed.
It looks small enough to attach it right behind my front horns, I might even be able to get the exit points on the same vertical plane, nested « head to tail ». If not for the time coherence, at least for the compactness and look, something like:
\
= ] /
/ [=
\
But I would also try other places, like down low firing up etc
That is a easy thing to get around.
Use something like Jetcarrier or similar freight services, that gives the purchaser a US mail box address🙂
Finally I went the TPL-75 route, I was lucky to find a used pair online.
The back can be removed like the big brother, same felt inside.
It is much smaller than the 150, and there’s even a smaller front plate in the box.
I wasn't able to find a good solution for the attachment with the 6’’, its motor is too heavy to keep inline with just zipties so I will need to build a small baffle with special care about the center of gravity.
But I had to test it, so I used a pair of Kartesian mid120 I have for a different project (a 3way closed that might never happen now 😛).
I wasn’t sure what to expect since it is very small (12cm), the dipole loss could be too much starting too high.
Well it’s not, the only issue is the sensitivity, kind of.
So :
Yeah funny looking, huge low mid and tiny high mid 😛
Here’s a full range response mic at 20cm, -43db:
And rouch off axis at 60cm by 22.5 degree to get an idea:
It’s at least 6db less sensitive than the 6mrn150d, but most of the high sensitivity of the SB is near the dipole peak so not very useful anyway. The surprise is that it can still go low enough for a 5-600Hz crossover point.
I did a quick tune yesterday, it sounded good, detailed, but something was off, the gain of rear firing highs was not so obvious.
And worst I clearly felt a big loss in dynamic, it’s only 5-6db less in headroom but it felt more than that.
Like everything flat and I needed to turn up and up, and I did and I came close to -5/-0db on the SHD and I don't like that.
Maybe just a psycho effect of the visually tiny mid, or just too much EQ cuts.
So I re-tuned today, following a new path, kind of inspired by the other thread about dipole measurements.
I’m not there yet as it was really quick but it's a first step so I:
Individual response, the three cones were super smooth:
The adjusted for listening position, 1 point:
While yesterday was more like:
There’s still a lot of work to do to optimise, but it sounds good, better than yesterday for sure, while it’s much less "flat".
I have the real airy sound of the tpl, and increased soundstage, well not larger but with a better spread, more ambiance.
The right balance between diffuse and detailed for me.
The horns, or the previous waveguided tweeters, would sometime call too much attention on details, they were hard to make disappear. Here it is much easier.
And dynamic is back too, this little mid is enough for me I guess. If I need more or if it feels strained I could add another one for mtm.
It can only improve from now on, as next steps would call for more measurements for better understanding of room effects, and eq accordingly to target +/- 3db or less.
I’ll keep it with minimal eq for few days/weeks, but I’ll probably try an LR12 on the mid/tweet too.
The back can be removed like the big brother, same felt inside.
It is much smaller than the 150, and there’s even a smaller front plate in the box.
I wasn't able to find a good solution for the attachment with the 6’’, its motor is too heavy to keep inline with just zipties so I will need to build a small baffle with special care about the center of gravity.
But I had to test it, so I used a pair of Kartesian mid120 I have for a different project (a 3way closed that might never happen now 😛).
I wasn’t sure what to expect since it is very small (12cm), the dipole loss could be too much starting too high.
Well it’s not, the only issue is the sensitivity, kind of.
So :
Yeah funny looking, huge low mid and tiny high mid 😛
Here’s a full range response mic at 20cm, -43db:
And rouch off axis at 60cm by 22.5 degree to get an idea:
It’s at least 6db less sensitive than the 6mrn150d, but most of the high sensitivity of the SB is near the dipole peak so not very useful anyway. The surprise is that it can still go low enough for a 5-600Hz crossover point.
I did a quick tune yesterday, it sounded good, detailed, but something was off, the gain of rear firing highs was not so obvious.
And worst I clearly felt a big loss in dynamic, it’s only 5-6db less in headroom but it felt more than that.
Like everything flat and I needed to turn up and up, and I did and I came close to -5/-0db on the SHD and I don't like that.
Maybe just a psycho effect of the visually tiny mid, or just too much EQ cuts.
So I re-tuned today, following a new path, kind of inspired by the other thread about dipole measurements.
I’m not there yet as it was really quick but it's a first step so I:
- measured each driver nearfield, at 10cm (already had an idea of the off axis response from before)
- corrected for dipole peak, just a notch, minimal on woofer and low mid, a bit more on high mid.
- corrected more the tpl as it was not as smooth as the horns
- defined XO point and slopes, the two mids called for a LR2 this time, but high mid to amt had to be LR4, break up is severe on the mid and I didn't want to eq to much, yet.
- then I just adjusted levels and time alignment at listening position
Individual response, the three cones were super smooth:
The adjusted for listening position, 1 point:
While yesterday was more like:
There’s still a lot of work to do to optimise, but it sounds good, better than yesterday for sure, while it’s much less "flat".
I have the real airy sound of the tpl, and increased soundstage, well not larger but with a better spread, more ambiance.
The right balance between diffuse and detailed for me.
The horns, or the previous waveguided tweeters, would sometime call too much attention on details, they were hard to make disappear. Here it is much easier.
And dynamic is back too, this little mid is enough for me I guess. If I need more or if it feels strained I could add another one for mtm.
It can only improve from now on, as next steps would call for more measurements for better understanding of room effects, and eq accordingly to target +/- 3db or less.
I’ll keep it with minimal eq for few days/weeks, but I’ll probably try an LR12 on the mid/tweet too.
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