I somehow tend to like quite simple 2-way projects. Of course not 6"+1" standard, but more sophisticated. Though I worked on several 4ways and 3ways, I still like and enjoy quite simple and easy projects.
21WE looks like the one of few 8inchers promising satisfactory results when used in 2-way. If it measures similar to 18WE......
I was looking for suitable 8inch for a long time, but so far nothing convinced me to give it a go. There is always at least one drawback, like sensitivity, distortion, FR linearity, or just lower extension.
21WE seems to offer it all. 8ohm version, as this one models better. I assume 40l enclosure.
Anyway, as the price of 21WE is as is, and moreover there are too many projects on my table already, this 2way will still be just in my had, at least for some time.
21WE looks like the one of few 8inchers promising satisfactory results when used in 2-way. If it measures similar to 18WE......
I was looking for suitable 8inch for a long time, but so far nothing convinced me to give it a go. There is always at least one drawback, like sensitivity, distortion, FR linearity, or just lower extension.
21WE seems to offer it all. 8ohm version, as this one models better. I assume 40l enclosure.
Anyway, as the price of 21WE is as is, and moreover there are too many projects on my table already, this 2way will still be just in my had, at least for some time.
I just know that Troels measured 4ohm version:
21WE-4542-T00_test
Some of 8inch midwoofers for 2way I have considered:
- NE225W: I used this woofer for bass duty, very very good, I see 2way with this driver very feasible
- Scan Speak 22W classic kevlars, unfortunately NLA
- Audiotechnology: maybe maybe
- WF223BD: might be good
- BC has some nice 8inch midwoofers, though I think they dont go low enough
- Scan Speak 22W Discovery, I think very underestimated midwoofer
- Audax HM210CP
https://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][category==8&index[shop_articles][data][shop_articles_id]=160]%[/category][category=]%[/category]
21WE-4542-T00_test
Some of 8inch midwoofers for 2way I have considered:
- NE225W: I used this woofer for bass duty, very very good, I see 2way with this driver very feasible
- Scan Speak 22W classic kevlars, unfortunately NLA
- Audiotechnology: maybe maybe
- WF223BD: might be good
- BC has some nice 8inch midwoofers, though I think they dont go low enough
- Scan Speak 22W Discovery, I think very underestimated midwoofer
- Audax HM210CP
https://www.audax-speaker.de/index.php?module=shop_articles&index[shop_articles][action]=details&index[shop_articles][category==8&index[shop_articles][data][shop_articles_id]=160]%[/category][category=]%[/category]
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I agree, not enough and not detailed data for proper decision yet. That clio distortion graphs are useless, all the useful data is squeezed in the very low part of the graph. It is just the feeling and experience with scan speak drivers that makes me think 21we will be special. I hope hificompass will get it under the mic. I cannot thank enough to Yevgeniy for his measurements and especially presenting them in readable form, with proper scales and zoomed useful data.
The combo of the 22W Discovery with the 15F midrange has a high bang for buck, it's used, for example, in John K's Nao Note II dipoles and in Troels' bookshelf speakers
Measurement of some protection elements of Bliesma done today. As I was not able to safely fix the toothpicks and grid to the waveguide, I did measurement on the loudspeaker on the floor. I did not bother with damping material around the speaker, which would remove some reflection....
Ok, the results..... 2 toothpicks seem to have very little efect around and above 20kHz. Original Bliesma grid did not hold on the place due to strong bliesma magnet, I had to use double sided sticky tape, and here we can see it caused small irregularities around 12kHz and above 20kHz. In both cases, I think the sticky tape protruding from the waveguide surface caused more problems than toothpicks and grid themselves.
For now, I incline to using of the grid. To fix it properly to waveguide, I would make 1mm circular groove and sit waveguide into it.
Hmm, I think I will experiment more with the grid, and fix the tape better.
Ok, the results..... 2 toothpicks seem to have very little efect around and above 20kHz. Original Bliesma grid did not hold on the place due to strong bliesma magnet, I had to use double sided sticky tape, and here we can see it caused small irregularities around 12kHz and above 20kHz. In both cases, I think the sticky tape protruding from the waveguide surface caused more problems than toothpicks and grid themselves.
For now, I incline to using of the grid. To fix it properly to waveguide, I would make 1mm circular groove and sit waveguide into it.
Hmm, I think I will experiment more with the grid, and fix the tape better.
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. I have experience with 10F and 15M Discovery, both great drivers with good sound. I just wish 15M was more linear in 2-3kHz region.
Progress update:
- drivers will be delivered next week, photos will follow
I attached 32W simulation, comparison of sealed, sealed with 0R5, and pasive radiators, both in 75l. Pasive radiator system with 2x30W scan speak PR per cabinet, system tuned to 20Hz. Simulation contains baffle step.
- drivers will be delivered next week, photos will follow
I attached 32W simulation, comparison of sealed, sealed with 0R5, and pasive radiators, both in 75l. Pasive radiator system with 2x30W scan speak PR per cabinet, system tuned to 20Hz. Simulation contains baffle step.
Attachments
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Pida
Calculating the PR response with my calculators shows that an enclosure volume of 75 L is too low for a flat low frequency response. The response is boosting. For a PR system with the 32W, a cabinet volume of 120 L is required.
Using two PR Scanspeak 30W, the mass on each PR has to be 400 g for a tuning at 20 Hz. That is a lot and not so ideal IMO.
A more interesting result ban be realized using 2x 10 inch Dayton DS270. They have a lower Vas than the 30W, a more stiff suspension. In 120 L a tuning frequency of 24 Hz can be realized with 200 g on each PR. That is more realistic.
Just to check. For 2 PR in the same cabinet, Vas and Sd have the double value.
For the same PR system in the same volume with 2 PR instead of 1 PR, double the mass for each PR is needed.
I use the VituixCAD Enclosure tool and the R.Small PR formulas for my calculations. Both almost have the same results. The VituixCAD Enclosure Tool works excellent and is very accurate.
I have enclosed my VituixCAD Enclosure files for the Scanspeak 30W and the Dayton DS270
Calculating the PR response with my calculators shows that an enclosure volume of 75 L is too low for a flat low frequency response. The response is boosting. For a PR system with the 32W, a cabinet volume of 120 L is required.
Using two PR Scanspeak 30W, the mass on each PR has to be 400 g for a tuning at 20 Hz. That is a lot and not so ideal IMO.
A more interesting result ban be realized using 2x 10 inch Dayton DS270. They have a lower Vas than the 30W, a more stiff suspension. In 120 L a tuning frequency of 24 Hz can be realized with 200 g on each PR. That is more realistic.
Just to check. For 2 PR in the same cabinet, Vas and Sd have the double value.
For the same PR system in the same volume with 2 PR instead of 1 PR, double the mass for each PR is needed.
I use the VituixCAD Enclosure tool and the R.Small PR formulas for my calculations. Both almost have the same results. The VituixCAD Enclosure Tool works excellent and is very accurate.
I have enclosed my VituixCAD Enclosure files for the Scanspeak 30W and the Dayton DS270
Paul, I tried 32W with 2x30W passive in 75l tuned to 20Hz in Vituix, see attachment. 30W has Mms 435g, and for two of them in 75l and 20Hz tuning I have to add ~90g to each. I am not sure I see any boosting.
I checked your files, thank you for them.
Is there any negative aspect of using passive radiators with Mms 435g and additional weight ~100g?
Generally I am not after the lowest possible extension with that driver and also like more reasonable cabinet volume. I chose this driver based on experience with 28W and other scan speak drivers. I also listened to Xavian Opus Magnum, using 8ohm version in 80l with 2x30W passive.
I checked your files, thank you for them.
Is there any negative aspect of using passive radiators with Mms 435g and additional weight ~100g?
Generally I am not after the lowest possible extension with that driver and also like more reasonable cabinet volume. I chose this driver based on experience with 28W and other scan speak drivers. I also listened to Xavian Opus Magnum, using 8ohm version in 80l with 2x30W passive.
Attachments
Pida
We used different settings in VituixCAD Enclosure.
I had chosen Rg = 0.5 E, and I did use other values for Qa and QL.
(I didn't see before that the number of PR's can be defined also, that is nice).
With Rg = 0.5 E, Qa = 100 and QL = 15, there is a boost of 1 dB at low frequencies, see attach.
With Rg = 0 E, like in your simulation, there is indeed no boost.
You add 180 g extra to the PR in your simulation. I understand that it is extra for each PR? Then the total moving mass is 435g + 180g = 615 g. That is a lot, but maybe that PR can handle that. If the minimum Mms is already 435 g and you can add extra weigth, I expect 180 g extra is no problem.
My last VituixCAD file again attached.
We used different settings in VituixCAD Enclosure.
I had chosen Rg = 0.5 E, and I did use other values for Qa and QL.
(I didn't see before that the number of PR's can be defined also, that is nice).
With Rg = 0.5 E, Qa = 100 and QL = 15, there is a boost of 1 dB at low frequencies, see attach.
With Rg = 0 E, like in your simulation, there is indeed no boost.
You add 180 g extra to the PR in your simulation. I understand that it is extra for each PR? Then the total moving mass is 435g + 180g = 615 g. That is a lot, but maybe that PR can handle that. If the minimum Mms is already 435 g and you can add extra weigth, I expect 180 g extra is no problem.
My last VituixCAD file again attached.
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I assume Rg can represent Rdc of the coil. I checked and it seems better to keep Rg~0.3ohm, and cabinet volume 85liters, with that the boosting is minimized. I am still not decided whether to go closed and PR in pasive crossover version, there is plenty of time to decide that anyway, and I will listen to active version before that anyway.
Yes, I have taken 0.5 E for the serial coil(s) Rdc. Rg = 0.3 E and Vb = 85 L seems to be ok.
With some dampening material inside the cabinet, Qa and QL become lower also. Qa = 20 and QL = 7 are more realistic values for a system with some filling in the cabinet.
To know it all more accurately, you need the measurements.
With some dampening material inside the cabinet, Qa and QL become lower also. Qa = 20 and QL = 7 are more realistic values for a system with some filling in the cabinet.
To know it all more accurately, you need the measurements.