Tweeter and WG was mounted in floorstanding eclosure, all edges rounded with R50mm, this is essential even when you use WG, at least for eclosures with normal width. This enclosure was 300mm wide.
I use Vituix to calculate DI graph. All my measurements show horizontals 0-90degreees, in 10deg steps. Verticals are not included. DI calculation is done for front horizontal plane. Vituix allows to set conditions for DI calculation spherical and cylindrical surface, and to include horizontals, verticals, and half space checker. To get DI for hemisphere I would have to include vertical responses.
I will check my setting later today. It should be spherical surface, horizontals and half space (though I think half space checker influences only polar response graph - angle scale).
More to it is here, roughly in the middle of the page:
Software
I believe some formulas can be found in Vituix manual, if I remember correctly.
I use Vituix to calculate DI graph. All my measurements show horizontals 0-90degreees, in 10deg steps. Verticals are not included. DI calculation is done for front horizontal plane. Vituix allows to set conditions for DI calculation spherical and cylindrical surface, and to include horizontals, verticals, and half space checker. To get DI for hemisphere I would have to include vertical responses.
I will check my setting later today. It should be spherical surface, horizontals and half space (though I think half space checker influences only polar response graph - angle scale).
More to it is here, roughly in the middle of the page:
Software
I believe some formulas can be found in Vituix manual, if I remember correctly.
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Pida, thanks for the information. I will have a closer look at it too.
I have the impression we use the same DI calculation, now I know that it is measured in an enclosure.
I did some simulations/calculations in single hemisphere of a speaker with X-over in the past. I use Leap for it, but it isn't possible to make a waveguide model in it, that is a pity.
I think the single hemisphere calculation is sufficient for a good evaluation of the speaker dispersion.
I have the impression we use the same DI calculation, now I know that it is measured in an enclosure.
I did some simulations/calculations in single hemisphere of a speaker with X-over in the past. I use Leap for it, but it isn't possible to make a waveguide model in it, that is a pity.
I think the single hemisphere calculation is sufficient for a good evaluation of the speaker dispersion.
IT SEEMS one important experiment is to design and build a 2-way using the AES TD8M midwoofer and Morel CAT 378 dome-waveguide _OR_ Wavecor tw030wa11_12 dome-waveguide.
If you already have the AES TD8M midwoofer at home, can you run a few sims and initiate group discussion which might motivate this build?
This work should also help a decision on the.... dome-waveguide vs. compression driver + horn ....discussion.
If you already have the AES TD8M midwoofer at home, can you run a few sims and initiate group discussion which might motivate this build?
This work should also help a decision on the.... dome-waveguide vs. compression driver + horn ....discussion.
I m hoping that i m not opening a can of worms again, but what do u think of BEYMA TPL-75 ? it looks good on the paper, a little low on sensitivity side tho.
92 dB and impedance is 5 Ohm, so won't fit work the requirement for an "8 Ohm" rating.
Maybe take a look at some AMTs?
Edit: the 25CS2.1-R, 29CM1.1-R and maybe 19CM1.1-C would fit the SPL and impedance requirements.
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Does it have to be 8 ohm? I mean, not even a wimpy amp should have a problem driving a 4 ohm tweeter if the other drivers are 8 ohms?
Well, this new Satori dome is 4 ohm 96dB, with a little padding I’m sure it could come close to 8 ohm. Just need to find a fitting wg.
Satori TW29DN-B Textile Dome Tweeter
Well, this new Satori dome is 4 ohm 96dB, with a little padding I’m sure it could come close to 8 ohm. Just need to find a fitting wg.
Satori TW29DN-B Textile Dome Tweeter
But it is 8ohm
AMT, have been mentioned before either too expensive or have high FS, but need to take a better look.
The 8 Ohm "rated impedance" spec in the Beyma data sheet is awkward. Take a look at the impedance curve and you'll see it's pretty much 5 Ohm.
According to the datasheet/catalogue, those Mundorf AMTs work well down to 2 kHz with a 6 dB/oct filter. A steeper filter will "relax" this even more. I have no personal experience with these, though.
Some information that can be used for the choice CD tweeter versus dome tweeter (probably in a waveguide), I did some DI calculations.
I have calculated the single half plane DI from 0 to 90 degrees horizontal of following drivers:
- CD tweeter 18Sound XT1086 + ND1075 (green curve)
- CD tweeter Selenium D220Ti (blue curve)
- Dome tweeter Monacor TD300 in WG300 (red curve)
- AE TD8M (grey curve) Leap model
Used off axis measurements of Kimmo Saunisto for the Monacor and the 18Sound Wave guides & horns and the Selenium from a list on the DIY forum, Great Waveguide List.
I did choose the Monacor, because I already have the 0 -90 degrees measurements of this driver.
I cannot add the DI of the Morel Cat378, because I don’t have all the 0 - 90 degrees off axis responses, and the DI value will be lower then.
Comparing the DI results, it changed my mind about CD tweeters. I thought they were much more directive than a dome tweeter in a waveguide.
I think a combi AE TD8M with a CD tweeter is feasible based on these (preliminary) DI calculations.
Between 2 and 4 kHz, the transition between the AE TD8M to the tweeter will be more smooth with the waveguide.
For the CD tweeter the mean DI is more flat above 2 kHz than the waveguide.
Remark these are infinite baffle values and DI will change in an enclosure, but the same for all, to be expected, not proven yet. Probably only below 1 kHz for the wide cabinet of this project. Already mentioned this before.
Remark also that I assume that all the drivers are measured on a large baffle and not in an enclosure.
This is draft information, but maybe useful for further discussion and extra investigation.
Edit: I don't know yet which horn is used for the Selenium in the off axis measurement I used.
I have calculated the single half plane DI from 0 to 90 degrees horizontal of following drivers:
- CD tweeter 18Sound XT1086 + ND1075 (green curve)
- CD tweeter Selenium D220Ti (blue curve)
- Dome tweeter Monacor TD300 in WG300 (red curve)
- AE TD8M (grey curve) Leap model
Used off axis measurements of Kimmo Saunisto for the Monacor and the 18Sound Wave guides & horns and the Selenium from a list on the DIY forum, Great Waveguide List.
I did choose the Monacor, because I already have the 0 -90 degrees measurements of this driver.
I cannot add the DI of the Morel Cat378, because I don’t have all the 0 - 90 degrees off axis responses, and the DI value will be lower then.
Comparing the DI results, it changed my mind about CD tweeters. I thought they were much more directive than a dome tweeter in a waveguide.
I think a combi AE TD8M with a CD tweeter is feasible based on these (preliminary) DI calculations.
Between 2 and 4 kHz, the transition between the AE TD8M to the tweeter will be more smooth with the waveguide.
For the CD tweeter the mean DI is more flat above 2 kHz than the waveguide.
Remark these are infinite baffle values and DI will change in an enclosure, but the same for all, to be expected, not proven yet. Probably only below 1 kHz for the wide cabinet of this project. Already mentioned this before.
Remark also that I assume that all the drivers are measured on a large baffle and not in an enclosure.
This is draft information, but maybe useful for further discussion and extra investigation.
Edit: I don't know yet which horn is used for the Selenium in the off axis measurement I used.
Attachments
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It's was Dayton Audio H10RW 10" Round Waveguide 1-3/8"- 18 TPI
Dayton Audio H10RW 10" Round Waveguide 1-3/8"- 18 TPI
Here you can aldo find the response with many different horns/waveguides
Selenium D220Ti-OMF-8 Compression Driver Horns Compatibility - AmpsLab
Paul,
Download the PDF below, it has a lot of information that may give you better information about D220 compression driver and helps in the decisional process.
https://www.google.com.br/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&cad=rja&uact=8&ved=2ahUKEwiXyYWzra_eAhUIC5AKHe-iAhEQFjAMegQIARAC&url=http%3A%2F%2Fwww.audioheritage.org%2Fvbulletin%2Fattachment.php%3Fattachmentid%3D77902%26d%3D1503091842&usg=AOvVaw3ellDqodQGNxKAqzAtvqza
The selenium horn HM17-25 is also a good option. Take a look in the datasheet.
https://www.parts-express.com/pedocs/manuals/264-308-selenium-hm17-25-manual.pdf
Download the PDF below, it has a lot of information that may give you better information about D220 compression driver and helps in the decisional process.
https://www.google.com.br/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&cad=rja&uact=8&ved=2ahUKEwiXyYWzra_eAhUIC5AKHe-iAhEQFjAMegQIARAC&url=http%3A%2F%2Fwww.audioheritage.org%2Fvbulletin%2Fattachment.php%3Fattachmentid%3D77902%26d%3D1503091842&usg=AOvVaw3ellDqodQGNxKAqzAtvqza
The selenium horn HM17-25 is also a good option. Take a look in the datasheet.
https://www.parts-express.com/pedocs/manuals/264-308-selenium-hm17-25-manual.pdf
Some mentioned this driver previously:
Peerless by Tymphany DFM-2544R00-08 1" Compression DFM Driver 8 Ohm
It looks like it could be a good candidate.
I tried to order some SEOS 10's, but it looks like they may be out of them at the moment. I've mailed them to see, if I can, I'll order a pair to measure.
I have a pair of B&C DE-250s, both titanium and polyamide diaphragms that I can measure if needed.
1" Horns I have on hand:
RCF HF101 - I love this one with the DE-250 and have used it in several horn systems over the last few years.
PRV Audio WG35-25-B - This is another fantastic wg. I think this is another 'QSC' clone that was popular in the econowave builds, like:
B-52 PHRN-1014 1" Horn 10" x 14" Bolt-On
299-2303 is still available.
I'm considering buying a pair of the Peerless by Tymphany dfm-2544r00 compression drivers to measure as well.
Not sure when Aatto is getting the AE drivers in, but I plan to start building the IEC baffle this weekend. It looks like I should be able to build the 175hz version easily enough.
Cheers,
Gable
EDIT - I forgot to mention I have a MiniDSP 4x10HD as well, that may make some initial crossover/measurement work a bit easier to iterate on.
Peerless by Tymphany DFM-2544R00-08 1" Compression DFM Driver 8 Ohm
It looks like it could be a good candidate.
I tried to order some SEOS 10's, but it looks like they may be out of them at the moment. I've mailed them to see, if I can, I'll order a pair to measure.
I have a pair of B&C DE-250s, both titanium and polyamide diaphragms that I can measure if needed.
1" Horns I have on hand:
RCF HF101 - I love this one with the DE-250 and have used it in several horn systems over the last few years.
PRV Audio WG35-25-B - This is another fantastic wg. I think this is another 'QSC' clone that was popular in the econowave builds, like:
B-52 PHRN-1014 1" Horn 10" x 14" Bolt-On
299-2303 is still available.
I'm considering buying a pair of the Peerless by Tymphany dfm-2544r00 compression drivers to measure as well.
Not sure when Aatto is getting the AE drivers in, but I plan to start building the IEC baffle this weekend. It looks like I should be able to build the 175hz version easily enough.
Cheers,
Gable
EDIT - I forgot to mention I have a MiniDSP 4x10HD as well, that may make some initial crossover/measurement work a bit easier to iterate on.
Lordsansui: thanks for the information, I will look at it.
Gable: that would be great if you can install a 150 Hz IEC baffle. Then we can start our own measurements also. Already to compare some tweeter drivers that you have at home.
To compare more CD tweeters and waveguide tweeters with each other and the match with the TD8M, I calculated the single half plane DI from 0 to 45 degrees horizontal, because the 0 - 45 degree measurements are available for more drivers.
- AE TD 8M Leap model (grey curve)
- CD tweeter 18Sound XT1086 + ND1075 (green curve)
- CD tweeter Selenium D220Di - Dayton H10RW (blue curve)
- Dome tweeter Monacor TD300 in WG300 (red curve)
- Dome tweeter R2904 – waveguide Visaton WG148 (violet curve) – measurement Pida in enclosure.
- Dome tweeter Morel Cat378 (yellow curve)
In the 3 plots, AE TD8M vs. CD tweeters, AE TD8M vs. dome waveguide tweeters and AE TD8M versus both.
IMO, some first conclusions can be made, suppose we will make a crossover around 2 kHz.
- The CD tweeters are more directive below 4 kHz, but they show a are more flat DI up to higher frequencies.
- The dome tweeters with waveguide are less directive below 4 kHz, but they show an increasing DI behavior up to high frequencies
- The Morel Cat378 has a strong leading DI response up to 10 kHz. I think it is not so good, there will be probably some lack of high frequency definition. I think it is caused by the small horn with its typical shape.
- Looking to these comparing results can explain why CD tweeters are playing with more upper frequency dynamics. They have another power distribution between 2 and 10 kHz, more constant directivity. I can understand why some people prefer this sound more than the one of a dome tweeter.
- The acoustical center of a horn tweeter will be positioned more backwards. Maybe a problem for a passive filter. A low X-over crossing will be more recommended probably.
- I think a speaker with smaller midrange with dome tweeter will sound more uniform in a room. Less dependent of the listening place and more filling the room with music power. Just because the DI mean value can be designed lower. The Monkey Coffin with a 3 inch midrange and dome tweeter will sound different in a room than a Tower XL with 8 inch midrange and CD tweeter for example. It will be a personal choice.
It can be expected that an 8 inch midrange with CD tweeter versus a dome tweeter with waveguide will be not so much different w.r.t. room power, but they will sound different because of other DI at high frequencies.
Gable: that would be great if you can install a 150 Hz IEC baffle. Then we can start our own measurements also. Already to compare some tweeter drivers that you have at home.
To compare more CD tweeters and waveguide tweeters with each other and the match with the TD8M, I calculated the single half plane DI from 0 to 45 degrees horizontal, because the 0 - 45 degree measurements are available for more drivers.
- AE TD 8M Leap model (grey curve)
- CD tweeter 18Sound XT1086 + ND1075 (green curve)
- CD tweeter Selenium D220Di - Dayton H10RW (blue curve)
- Dome tweeter Monacor TD300 in WG300 (red curve)
- Dome tweeter R2904 – waveguide Visaton WG148 (violet curve) – measurement Pida in enclosure.
- Dome tweeter Morel Cat378 (yellow curve)
In the 3 plots, AE TD8M vs. CD tweeters, AE TD8M vs. dome waveguide tweeters and AE TD8M versus both.
IMO, some first conclusions can be made, suppose we will make a crossover around 2 kHz.
- The CD tweeters are more directive below 4 kHz, but they show a are more flat DI up to higher frequencies.
- The dome tweeters with waveguide are less directive below 4 kHz, but they show an increasing DI behavior up to high frequencies
- The Morel Cat378 has a strong leading DI response up to 10 kHz. I think it is not so good, there will be probably some lack of high frequency definition. I think it is caused by the small horn with its typical shape.
- Looking to these comparing results can explain why CD tweeters are playing with more upper frequency dynamics. They have another power distribution between 2 and 10 kHz, more constant directivity. I can understand why some people prefer this sound more than the one of a dome tweeter.
- The acoustical center of a horn tweeter will be positioned more backwards. Maybe a problem for a passive filter. A low X-over crossing will be more recommended probably.
- I think a speaker with smaller midrange with dome tweeter will sound more uniform in a room. Less dependent of the listening place and more filling the room with music power. Just because the DI mean value can be designed lower. The Monkey Coffin with a 3 inch midrange and dome tweeter will sound different in a room than a Tower XL with 8 inch midrange and CD tweeter for example. It will be a personal choice.
It can be expected that an 8 inch midrange with CD tweeter versus a dome tweeter with waveguide will be not so much different w.r.t. room power, but they will sound different because of other DI at high frequencies.
Attachments
I know miniDSP 4x10HD very well. I already made several designs with it for some audio friends.
Using the advanced programming with biquads you can exactly design what you want. Also possible to make high slope filtering with them.
I made a 5th order elliptical filter with it, very well performing (IMO).
Also the miniDSP DAC sounds very good, very neutral and detailed, I like it.
Gable, that is great, that peerless driver been mentioned quite few times here
Unfortunately I do not have updates on AE drivers yet, it's been almost two weeks since the day of order.
Paul, fantastic ! very helpful as usual
if the Morel doesn't fit well, we may have a hard time finding a dome tweeter, AMTs have been brought up several times, the Mundorf catalog mbrennwa mentioned has good drivers but the ones that would fit are the same price as TPL-150, my point is if we want to push the price limit we have good options and as kaffimann suggested we can have a "unlimited" version w AE drivers, but unfortunately that would not be possible for me at the moment if I have to be the one to buy the drivers and build it.
Unfortunately I do not have updates on AE drivers yet, it's been almost two weeks since the day of order.
Paul, fantastic ! very helpful as usual
if the Morel doesn't fit well, we may have a hard time finding a dome tweeter, AMTs have been brought up several times, the Mundorf catalog mbrennwa mentioned has good drivers but the ones that would fit are the same price as TPL-150, my point is if we want to push the price limit we have good options and as kaffimann suggested we can have a "unlimited" version w AE drivers, but unfortunately that would not be possible for me at the moment if I have to be the one to buy the drivers and build it.
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Interesting thread, can answer some of the questions :
what are the drawbacks of compression drivers?
what are the drawbacks of compression drivers?
If a ribbon or AMT is considered as tweeter, we best look to the directivity in a single hemisphere, which means including vertical off axis measurements. And compare it with the hemisphere results of the TD 8M.
It seems to me a not too expensive dome tweeter to be mounted on a waveguide can be the best solution for the tweeter dome version. I am searching but not found yet...
There are Dayton, Monacor, Visaton, Jantzen,...and probably other waveguides. Just to know which drivers does fit on them. I haven't practical experience with it. The tweeter without waveguide must have a minimum sensititvity of 91 dB and being an 8 ohm version.
I'm gonna search further.
Aatto, Scanspeak R2904-70000 is too expensive for you? With the Visaton WG148, it is a known concept and maybe Mbrennwa will apply it also in the Monkey Coffin.
It seems to me a not too expensive dome tweeter to be mounted on a waveguide can be the best solution for the tweeter dome version. I am searching but not found yet...
There are Dayton, Monacor, Visaton, Jantzen,...and probably other waveguides. Just to know which drivers does fit on them. I haven't practical experience with it. The tweeter without waveguide must have a minimum sensititvity of 91 dB and being an 8 ohm version.
I'm gonna search further.
Aatto, Scanspeak R2904-70000 is too expensive for you? With the Visaton WG148, it is a known concept and maybe Mbrennwa will apply it also in the Monkey Coffin.
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