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Cardioid speakers
Old 3 weeks ago
  #31
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@ Jens : Do you remember what X-overs you used for your Greger-Avicii edition and if any ”special tricks” were needed?

The progress in my room has for various reasons been at a standstill for some years but is now picking up again. All drivers are identical to the ones in your Greger except for maybe impedance, mine are 8 ohms. The lower part of the cabinet only works as a speaker stand but its volume can later be used if a vented speaker is wanted. The TD 12M sits in its own sealed damped compartment about 18,4 L (prior to damping material for a bit larger virtual volume). I believe the Greger’s volume is quite close. The TPL 150H’s plastic housing has been removed and it also has its own sealed and damped compartment about 3,7 L. C-c distance 272 mm between the midbass <=> TPL 150H. The AE 18+ driver is 68 cm beside / away. The cabinet goes into a dog house, so the baffle area around TD 12M is about 86 cm wide. Above and behind a combined superchunk and membrane absorber.

(Setup is a 3x60 degree listening triangle, 326,5 cm c-c between front speakers and head about 13 cm in front of speaker crossing. Top of cabinet is 104 cm above floor. Listening height varying between 86-97 cm in a recliner.)
Attached Thumbnails
Cardioid speakers-59a-tomlada-i-hundkojan.jpg   Cardioid speakers-63b-fardigbetsad-lada-i-hundkojan.jpg  
Old 3 weeks ago
  #32
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Jens Eklund's Avatar
If I recall correctly, I think it was at 1250 Hz. Standard 4th order LR. No trix needed as I recall (except signal alignment obviously, don't recall how much though but you'll want to measure it anyway).



EDIT:

I checked the polar for a CC of 270-280 mm between drivers, and 1250 Hz results in a null beam exactly at 30 degrees so that makes sense for me (avoiding desk reflection as discussed previously). A 680 mm CC (mid – woofer) would suggest that you could X-over as high as 300 Hz without issues (possibly less issues than if lower due to the directivity it would provide in the horizontal plane). The TD18H+ would perform better than the TD12M up to at least 500 Hz I would guess, possibly even 1 kHz or higher.

Last edited by Jens Eklund; 3 weeks ago at 09:01 PM..
Old 3 weeks ago
  #33
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Jens Eklund's Avatar
Quote:
Originally Posted by Adhoc View Post
The TPL 150H’s plastic housing has been removed and it also has its own sealed and damped compartment about 3,7 L.
Have you measured the difference it made (if any)? I didn't bother with that.
Old 3 weeks ago
  #34
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Thanks. I will experiment from 1200 Hz and up to 1540 or so. If calculations and theory are correct the TD 12M's diameter 243 mm should have about 80 degree horizontal dispersion around 1540 Hz, like the TPL's.

In some good threads at diyaudio.com and a German site it was found to be benefical to remove the plastic housing and have the TPL open backwards in a separate housing with some light weight damping. The plastic housing has only some 10 mm felt at the back. So, I took their findings and measurements for granted and removed it.
Old 3 weeks ago
  #35
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Jens Eklund's Avatar
Quote:
Originally Posted by Adhoc View Post
Thanks. I will experiment from 1200 Hz and up to 1540 or so. If calculations and theory are correct the TD 12M's diameter 243 mm should have about 80 degree horizontal dispersion around 1540 Hz, like the TPL's.
1250 Hz is already pushing it ... Check XDir (Tolvan) if you haven’t already. But I guess if only sitting position is relevant and ceiling is well treated (lobe at about 55 deg if 1540 Hz will be as strong as direct sound …) it might work.


Quote:
Originally Posted by Adhoc View Post
In some good threads at diyaudio.com and a German site it was found to be benefical to remove the plastic housing and have the TPL open backwards in a separate housing with some light weight damping. The plastic housing has only some 10 mm felt at the back. So, I took their findings and measurements for granted and removed it.
Yes, I thought of doing it but if I´m not mistaken, there was another thread in another forum (can’t remember which one) that didn’t find any measurable difference, so that helped me decide not to do it (plus dozens of other reasons … ). If I still used that driver I would have done some tests naturally, but since I stopped using it that never happened.

see my edit on post 32.
Old 3 weeks ago
  #36
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Thanks for the suggestions Jens, much appreciated.

The seating position is the only relevant one for me. I checked out XDir in Svante's Tolvan a long time ago but I don't recall now what it showed. If 1540 Hz or so gives a lobing at 55 degrees it ends up in the cloud, about 3 dm from the front of it (W 240 x L 165 cm x 140 mm of Flexibatts) and stretches backwards behind listening position.

I think no matter what x-over frequency, it will be some sort of compromise. As low as 1250 Hz seems like a "stretch" for the TPL. The null downwards at 30 degrees with 270-280 mm c-c is of little value for me, while it would be good for some others (I don't have a desk in front, it's a listening room, open towards speakers). More important then that a 30 degree null upwards passes over the head. I think I will check out your suggestion for a "higher" cross over between woofer and midbass. If I remember correctly though, John at Acoustic Elegance mentioned the AE 18+ with a dust cap (instead of the usual aluminium phase plug) has a resonance around 500 Hz.
Old 3 weeks ago
  #37
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Jens Eklund's Avatar
Quote:
Originally Posted by Adhoc View Post
Thanks for the suggestions Jens, much appreciated.

The seating position is the only relevant one for me. I checked out XDir in Svante's Tolvan a long time ago but I don't recall now what it showed. If 1540 Hz or so gives a lobing at 55 degrees it ends up in the cloud, about 3 dm from the front of it (W 240 x L 165 cm x 140 mm of Flexibatts) and stretches backwards behind listening position.

I think no matter what x-over frequency, it will be some sort of compromise. As low as 1250 Hz seems like a "stretch" for the TPL. The null downwards at 30 degrees with 270-280 mm c-c is of little value for me, while it would be good for some others (I don't have a desk in front, it's a listening room, open towards speakers). More important then that a 30 degree null upwards passes over the head. I think I will check out your suggestion for a "higher" cross over between woofer and midbass. If I remember correctly though, John at Acoustic Elegance mentioned the AE 18+ with a dust cap (instead of the usual aluminium phase plug) has a resonance around 500 Hz.
So what about 45 degrees ... the lobe is only down 1 dB at 45 deg. compared to direct lobe ... if 1540 Hz X-over that is.

Dust cap version of TD18H+ has a slight resonance at 810 Hz (around 800 Hz according to John and 810 Hz confirmed by my measurements), so up to 300 Hz is absolutely fine. Response and distortion is excellent up to about 360 Hz.
Old 3 weeks ago
  #38
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Impressive speakers you've got there Jens

Out of curiosity, how high is the acoustic axis on these ? Taking the 18in woofers as reference I would say around 140/145cm but I may be wrong.
Old 2 weeks ago
  #39
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Quote:
Originally Posted by Scholl View Post
Impressive speakers you've got there Jens
Thanks!

Quote:
Originally Posted by Scholl View Post
Out of curiosity, how high is the acoustic axis on these ? Taking the 18in woofers as reference I would say around 140/145cm but I may be wrong.
The 0 degree acoustic axis is at 1460 mm height. However, each system is calibrated individually on site, thus making sure that the direct sound is measuring flat (or flat relative to target) at the sweet spot. At normal distance (about 1700 mm), this results in a -7 degree angle form normal at ear height when sitting. This also results in the +7 degree axis measuring flat as well (since it´s a symmetric driver setup) which is exactly where the average (male … sorry ladies) ear position ends up when standing up. This is a deliberate design decision in order to provide accurate frequency response regardless working sitting or standing up.

Cardioid speakers-acoustic-axis-olo-48.jpg
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Cardioid speakers-acoustic-axis-olo-48.jpg  
Old 2 weeks ago
  #40
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Interesting, thanks for the info !
Old 2 weeks ago
  #41
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Quote:
Originally Posted by Jens Eklund View Post
So what about 45 degrees ... the lobe is only down 1 dB at 45 deg. compared to direct lobe ... if 1540 Hz X-over that is.

Dust cap version of TD18H+ has a slight resonance at 810 Hz (around 800 Hz according to John and 810 Hz confirmed by my measurements), so up to 300 Hz is absolutely fine. Response and distortion is excellent up to about 360 Hz.
That is a valid point (the 45 degrees) which I have already noticed with REW. With previous speakers I sat at a longer distance from the speakers so the cloud had a better coverage area versus the ceiling reflection <=> listening position. The ETC used to be about -20 dB. With the new speakers and a closer listening distance the ETC gets worse, so I will squeeze in an additional framed cloud 1,2x2,4 m in front of the existing one. Regrettably max depth will be around 17 cm due to practical reasons. With hinges + chains it can be tilted down towards the front though, to 26 cm below the ceiling.

I have 4 pcs Isover Piano, air flow resistivity around 5000 Pa.s/m² 1170 x570 x 210 mm thick as leftover material. If I compress it to 170 mm the air flow resistivity will increase, a guesstimate to between 7000-9000 Pa.s/m². As a non tilted cloud this actually shows better absorbtion in Porous Absorber below 200 Hz, but a bit worse between 200-800 Hz (still above 0,8 though). From Soundflow, do you think, I'm playing it cheap and should buy some other insulation for best performance instead.
Old 2 weeks ago
  #42
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Jens Eklund's Avatar
I'll do some simulations in Soundflow once back in office. Is the fibre orientation in Isover random or layered? If not random; go with flexibatt.
Old 2 weeks ago
  #43
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The interior of Isover Piano has fibre orientation along the 1170 mm side and is layered. The flat facing has some thin random fibre orientation, -like from a slurry for adhesive purposes and a "hard" surface.

As the cloud's size ratio will be 1:2, fibre orientation can go along the room width or along its length. Some partions / "wave guides" will be used inside the cloud frame so the insulation fits snugly and doesn't sag down too much due to gravity, putting pressure on the fabric. (Will do the same also if the heavier Flexibatts with random fibre direction are used.)
Old 2 weeks ago
  #44
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Even if ignoring the non-random fibre orientation in Isover Piano, Rockwool Flexibatts still outperforms Isover piano, and even if compressed (I just took the values and added 20 %, about the same increase as the decrease in thickness):
Cardioid speakers-170-mm-wool-45-degrees-incidence.jpg

The non-random fibre orientation for Isover will most likely further decrease the performance but to what extent, I don’t know.
Attached Thumbnails
Cardioid speakers-170-mm-wool-45-degrees-incidence.jpg  
Old 2 weeks ago
  #45
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Quote:
Originally Posted by Jens Eklund View Post
Even if ignoring the non-random fibre orientation in Isover Piano, Rockwool Flexibatts still outperforms Isover piano, and even if compressed (I just took the values and added 20 %, about the same increase as the decrease in thickness):


The non-random fibre orientation for Isover will most likely further decrease the performance but to what extent, I don’t know.
Many thanks Jens.

I got similar results when I simulated in Porous Absorber. It evens out around 280 Hz or so between the alternatives but the compressed Isover Piano in "Porous Absorber theory" slightly outperforms the Flexibatts below that. In Soundflow it is the other way around. I guess Soundflow is more "true", as it considers more parameters like weight / m². The settings in Porous absorber were Miki and 45 degrees incidence.

I can always start with some compresssed Isover Piano as those are available. With hinges on the cloud's frame it will be easy to lower the frame and replace the Piano with Flexibatts if ETC will show replacement as necessary. As it is, it's not written in stone where to cross over from the 4 x 18" woofers to the 12" midbass drivers and the TPL 150H. (The 18" drivers are at 1/4 from sidewalls and ceiling / floor with room 419 cm wide x 220 cm height.)
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Cardioid speakers-porous-absorber.jpg  
Old 2 weeks ago
  #46
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Yes; Soundflow simulations are more accurate due to more data being included in the model. However, as long as the fibre orientation is not parallel to the ceiling (if you use Isover Piano), I wouldn’t worry too much about the small theoretical difference.
Old 1 week ago
  #47
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I apologize for a late answer. With new speakers and a change to a closer distance speaker <=> LP than before, the 45 degree upward ceiling reflection ends up just in front of the existing cloud. So I decided to first move it 90 cm forward so the reflection ends up in the middle of the cloud. After all, the ceiling reflection was below -20 dB before the change.

Good move to start with I thought and a bad one. Lifting up the cloud to the new position one knee twisted with a sound one doesn't like to hear. Some X-rays at hospital showed the meniscus wasn't in the best of shape any more. Nothing serious though, some time ahead on crutches.

Good and cheap advice with arranging the Isover's fibre direction perpendicular to the ceiling, -should show a bit higher airflow resistivity compared to parallell when the cloud can't be very thick, -thanks!
Old 1 week ago
  #48
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Quote:
Originally Posted by Adhoc View Post
I apologize for a late answer. With new speakers and a change to a closer distance speaker <=> LP than before, the 45 degree upward ceiling reflection ends up just in front of the existing cloud. So I decided to first move it 90 cm forward so the reflection ends up in the middle of the cloud. After all, the ceiling reflection was below -20 dB before the change.

Good move to start with I thought and a bad one. Lifting up the cloud to the new position one knee twisted with a sound one doesn't like to hear. Some X-rays at hospital showed the meniscus wasn't in the best of shape any more. Nothing serious though, some time ahead on crutches.

Good and cheap advice with arranging the Isover's fibre direction perpendicular to the ceiling, -should show a bit higher airflow resistivity compared to parallell when the cloud can't be very thick, -thanks!
Sorry to hear!

Acoustics can be dangerous … Let´s hope it was worth it.
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