AudioCircle
Audio/Video Gear and Systems => Open Baffle Speakers => Topic started by: Rudolf on 20 Jan 2008, 05:19 pm
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I believe most of us still wonder how the different dipole frame types really differ from one another and what type to choose. So I built different frames of almost the same size for one driver, the Visaton W250 8 Ohm. All frames are 30x30x30 cm cubes outside, with the I-frame (aka OB) being just the driver mounting baffle for the H- and U-frame.
U-frame
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/U-frame.JPG)
H-frame
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H-frame.JPG)
M-frame
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/M-Frame.JPG)
I-frame aka open baffle
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/I-Frame.JPG)
The following measurements where done with the mike on the floor at 60 cm distance from the front plane of the frames. The I-frame was measured at 75 cm distance to put the speaker at the same distance as in the H- and M-frame.
Measurements are not gated, so you see some room response and the influence of the rear wave, but the positions of frame and mike were identical for all frames:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB%20and%20H-Frame.gif)
Black line is the "Open Baffle". Red is the H-frame "top down". This means that the H-frame is open to the top. Green is the H-frame as shown in the pictures.
I see this as another demonstration of how much bass energy you loose in "open" bass constructions. Regarding the H-baffle: I know that H-baffles of greater vertical proportions are less prone to bass loss when used with an open top. But for a square H-baffle a closed top seems to be mandatory.
Note that the open baffle looses almost 9 dB compared to a closed H-frame while not having any real benefit up to 600 Hz.
Next diagram compares the front radiation of the H-, M- and U-frame. Up to 200 Hz it is almost the same for all frames, even with the driver in the U-frame being 15 cm closer to the mike than in the H- or M-frame.
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_M_U_front.gif)
Above 200 Hz there are big differencies between the frames. I will discuss them in a following posting comparing the front/rear radiation of the different frame types.
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Rudolph,
Wouldn't you agree that these baffle shapes are for use below say 200hz?
Wouldn't you also agree that nearfield measurements of an open alignment in the bass region are pretty much useless, because the rear wave delay distance is significant in comparison to the mic distance?
Where's your damping for the U, since a U-baffle doesn't perform properly without addressing the lumped mass behavior of the air in the cavity?
Don't get me wrong, I applaud the effort and sharing. I just question the test conditions.
John
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From the last diagram in my first posting it looks like there isn´t much difference below 200 Hz between the I-, H-, M- and U-frame. So let us look closer how the front and rear radiation vary for each frame:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/I-Frame.gif)
For the I-frame there is practically no difference between front and rear up to 600 Hz. Equalizing from 500 Hz down and crossing at 2 kHz to a tweeter looks like an easy way, albeit at a very low level of efficiency. But of course that little Visaton driver would bottom out almost immediately. :nono:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H-Frame.gif)
The H-frame will peak at 200-300 Hz and needs some more care for those peaks and dips. But the front/rear radiation symmetry is on par with the OB up to 800 Hz.
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/M-Frame.gif)
The M-frame peaks at the same frequency as the H-frame, but with a more pronounced peak and following dip. This calls for a much lower X-over point. One could argue whether the better impulse compensation (mechanically) of a two-driver-M-frame is worth the effort. :?
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/U-Frame_1.gif)
At first glance the undamped U-frame looks like the H-Frame, but with much worse front/rear symmetry. But this diagram does not tell the whole story. With the mike 60 cm from the box front, it effectively is 90 cm from the rear when taking the measurement.
With equal distance from the mike to the front and back of the driver the SPL looks like this:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/U-Frame_2.gif)
The U-frame calls for detailed compensation of the front/back radiation difference as JohnK has shown. For anybody without the means to tame the U-frame properly, the H-frame looks like the better bass dipole IMHO.
Thanks for your attention. How do you think about it?
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Rudolf,
Could you make an I-frame with the woofer placed close to the floor @18"w x 24"h ( @45cm x 61cm? ) to measure for comparison to the H-frame?
I appreciate your time and effort to make measurements. :thumb:
Thanks,
Lin
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Rudolph,
Yes I agree, however, for those of us who use the woofers only to fill in the bass, it's really only the response difference below 200hz that's important. Damping U's for that purpose is pretty easy. Some of JohnK's stuff outlines the differences in the alignments, which require mic distances of 2 or more meters to properly quantify. I appreciate that you're looking at something different, the higher frequency peaks and troughs, which is why you measure that way.
Take care,
John
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Rudolph,
Wouldn't you agree that these baffle shapes are for use below say 200hz?
John,
By and large, yes. Of course these comparisons are not relevant if one wants his driver to reproduce a range from 50-5.000 Hz.
Wouldn't you also agree that nearfield measurements of an open alignment in the bass region are pretty much useless, because the rear wave delay distance is significant in comparison to the mic distance?
All diagrams show a dipole roll-of of at least 10 dB. So it isn´t nearfield anymore. And these are just comparable measurements under a given condition. No filters, no EQ, no optimized front wall reflections. They are not intended as building instructions - just as food for thought.
Where's your damping for the U, since a U-baffle doesn't perform properly without addressing the lumped mass behavior of the air in the cavity?
You were just a bit too fast with your answer. :wink: Hope the second part of my demonstration shows that I want to rise attention for the shortcomings of an undamped U-frame.
Don't get me wrong, I applaud the effort and sharing. I just question the test conditions.
John
Hey man, you can´t question the test conditions. It´s my posting, and I´m king here. :green:
But of course you can question the relevance of my findings. That´s up to everybody reading this. I just do what I can. :thumb:
BTW: And certainly I would not mess with chipboard boxes in the rainy winter if I had the means to be in CR like you. :drool:
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Rudolf,
Could you make an I-frame with the woofer placed close to the floor @18"w x 24"h ( @45cm x 61cm? ) to measure for comparison to the H-frame?
Lin,
the gods are with you! :wink: I found an old piece of chipboard 50x70 cm. I allow for ONE cut to size it for your taste. Tell me where. And do you want the OB standing or with the long side to the floor?
@ all else: I don´t intend to make it a habit building and measuring baffles for individual members of this fine forum. :lol:
So please refrain from asking what else chipbord sizes I have in my basement. :green:
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@ all else: I don´t intend to make it a habit building and measuring baffles for individual members of this fine forum. :lol:
So please refrain from asking what else chipbord sizes I have in my basement. :green:
:scratch: How about measuring the same baffle at a few different distances? aa
John
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Do I steer the whole thing wrong by asking what you think sounds the best? I would be interested in that. I know that the measurements are of significant interest to many, but I would like to try to tie some subjective impressions (yours) to the graphs that I see.
Just my ask! I will stay away from asking about the various sized boards, unless you happen to have a 90cmx120cm...
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Rudolf,
My thinking was 45cm wide (I just threw out a # on height :scratch:) because a few OB'ers feel that @45cm (17" to 18" for us odd balls) is a good compromise between bass rolloff and imaging.
I'm curious as to how an I-baffle of this width (your piece of chipboard acting as the lower half of a full baffle with a FR driver on top) measures compared to your H-baffle.
Thank you very much,
Lin
PS- I will PM you all the other sizes to cut. :lol:
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Let me contribute with a Topless-U measurement. It is my 'Volks-OB' Bass unit A&D R1524 with no crossover that is measured 65 cm in front and back.
The red curve is the front measurement. In room measurement and mic as Rudolf put it. Resolution is 1/24 octave.
(http://www.audiocircle.com/image.php?id=13297)
I think the Topless-U also deserves a place in this discussion on the basis of this measurements. With a suitable element the Topless-U can also be made
very small as these simulations with MJK's Math-Cad models prove. It is with the actual A&D R 1524 15" speaker, the upper simulation is with the actual
height of 60 cm and 30 cm 90 degree wings from the 40 cm wide baffle, the lower simulation is with 45 cm height and same 30 cm wings.
(http://www.audiocircle.com/image.php?id=13298)
/Erling
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Lin,
No estimation but the simulation of my A&D 1524 on a 45 x 60 cm baffle looks like this (Bass-center 25 cm above floor):
(http://www.audiocircle.com/gallery/albums/userpics/50000/1524__45x60_cm.JPG)
/Erling
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:scratch: How about measuring the same baffle at a few different distances?
John
Good idea, John. I will make that part of the agenda.
My thinking was 45cm wide (I just threw out a # on height :scratch:) because a few OB'ers feel that @45cm (17" to 18" for us odd balls) is a good compromise between bass rolloff and imaging.
I agree. 45 cm seems to be a common width. Hopefully I can get at it before the weekend.
Do I steer the whole thing wrong by asking what you think sounds the best? I would be interested in that.
I have not listened to anything but test tones with these frames. But I believe that it depends totally on the proper x-over and EQ, whether those frames sound well or not.
If you look at the comparison of the different frames (second diagram of my first post) there is practically no difference below 150 Hz. Everything that will make them sound different stems from the different response above 150 Hz. If you put a 24 dB/oct low pass filter at 80 Hz, you hardly need any compensation above 150 Hz and all frames will sound the same.
Without a x-over, the H-frame is +/- 5 dB from 200-2000 Hz, which isn´t too bad sounding. The M-frame will have +/- 10 dB, which IS bad. The U-frame has some peaks around 200 Hz but doesn´t look too bad elsewhere.
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Lin,
No estimation but the simulation of my A&D 1524 on a 45 x 60 cm baffle looks like this (Bass-center 25 cm above floor):
How close to the floor is the bottom edge of driver?
Thanks,
Lin
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Just 5 cm (2") from the floor both in the real OB and the simulation.
/Erling
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Hardware is on location. Measurements will have to wait till tomorrow:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_I-frame.JPG)
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Rudolf, - After you test Lins baffle with the driver on the bottom would you flip it "upside down", and see what it does with the driver on top?
Thank you!
Bob
EDIT: And move the mic vertically to correspond to the center height of the driver too please.
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Rudolf, - After you test Lins baffle with the driver on the bottom would you flip it "upside down", and see what it does with the driver on top?
Thank you!
Bob
EDIT: And move the mic vertically to correspond to the center height of the driver too please.
It will lose a lot of output.
Lin
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Seconded from Bob in St. Louis.
Rudolf, I suppose Bob's request is OT, but it would be very instructive, and in particular for those of us who use a separate midrange baffle, either for isolation reasons, or to optimise the step response, to see what happens.
Having done a lot of simulating in The Edge, there can be advantages in midrange reponse in having the speaker near the top of the baffle for the midrange/full-range (lots of qualifications).
If you can see your way clear......?
Thank you.
David
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My results comparing these dipols: H-frame of 30x30x30 cm and OB of 70x45 cm.
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_I-frame.JPG)
Please note that all measurements were done with two drivers. I did not exchange one driver between H-frame and OB. All measurements were done with the dipoles at the same position. All measuring distances are from the driver plane. Since the measurements are not gated you see a lot of room influences. But they are absolutely identical for both dipoles.
I start with a direct comparison of OB and H-frame. Mike positions were at 60, 120 and 260 cm distance and 0, 70 and 110 cm height from the floor respectively.
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_OB_1.gif)
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_OB_2.gif)
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_OB_3.gif)
Thank you Lin for suggesting the 70x45 cm baffle. It looks like it has just a little less bass efficiency than the H-frame.
Next two pictures show the response for each dipole with rising distance:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_6_12_26.gif)
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_6_12_26.gif)
Next I turned the OB upside down. The driver is now at 56 cm height. Measurements at 120 and 260 cm show what is lost and gained when comparing to the woofer at the bottom:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_du_12.gif)
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_du_26.gif)
My last diagram is a comparison of the "high" driver measured closely (20 cm) on axis and at 120 and 260 cm distance. It will give you an idea how the dipole roll of becames more severe with rising distance.
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_u_2_12_26.gif)
Interpretation is up to the forum community. :scratch:
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Rudolf,
Thanks again for your time and effort, it is much appreciated. :thumb:
Lin :)
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Thank for trying my suggestion Sir!!
Bob
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Hi Rudolf, and thanks for your contribution to some hard research.
(http://edge visaton 2 w250.jpg)
This is my attempt at simulating the 'driver up' configuration (at 260 cm), noting that The Edge doesn't take floor reflections into account.
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Obviously the screen capture didn't come through.
Can anyone help me.
The image insertion read: (http://edge visaton 2 w250.jpg).
Is this the right format?
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It seems that even writing the text creates an image that won't insert.
I'll try to fool it by trying to show what I inserted this way:
"square bracket"img"square bracket"edge visaton 2 w250.jpg"square bracket"/img"square bracket"
What's wrong (the "square brackets" point the right way)?
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Rudolph,
Interesting stuff. What surprises me is that the measurement distance only seems to show a difference in the general slope of the bass response with the woofer up away from the floor. Can you tell us some general info about the room size and approximate speaker placement for your measurements. I think I need that to wrap my brain around your results. Again, thanks for the effort and for sharing.
John
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Yes, great effort. :thumb:
Thanks for taking the time to post your measurements. Very interesting.
Did you run impedance measurements for the various configurations as well?
Cheers
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In the absense of the Edge graph, it is impossible to show a comparison, but the most notable difference is that the response is "flat" down to around 300 Hz, and -3 dB at about 170 Hz as it develops the 6 dB per octave loss (when I say flat, a 3 dB peak occurs at 700 Hz, and a 2 dB peak around 2 kHz).
This makes an interesting comparison with your "real world" measurements showing a drop off at around 500? Hz, and -3 dB at, say, 350? Hz.
I can only invite those interested to try The Edge themselves, but it appears that it is almost twice as optimistic as these real measurements show.
David
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What surprises me is that the measurement distance only seems to show a difference in the general slope of the bass response with the woofer up away from the floor. Can you tell us some general info about the room size and approximate speaker placement for your measurements.
John,
the room is roughly 5,3 x 4,2 m with the OB standing 1 m in front of the front wall (4,2 m wide). There is a 30 cm deep open rack on the wall behind the OB. The baffle is placed at 2/5 of the room width. Indeed the measurements show less difference between the driver positions than one might expect.
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(http://www.audiocircle.com/image.php?id=13316)
I've finally remembered how to post an image.
So as far as I can tell, the Edge simulation suggests lower frequency extension at Fe than actual measurements show (and given that it is a simulation of a baffle in free air, i.e. not resting on the floor, you might expect it to be a bit higher).
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Here is the correct Sd :duh:
(http://www.audiocircle.com/image.php?id=13318)
This graph especially begs the question: where is Fe?
What is correct, that there is a reference level with a large peak, or that Fe is the top of the peak, with some unexplained? higher frequency baffle drop-off?
(The second scenario doesn't? seem to accord with your graphs, except in so far as the driver itself has a high frequency roll-off).
David
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My measurements give me the opportunity to compare the real world with some simulations. David has already shown, that EDGE on itself does not help much for lower frequencies (albeit simulating in EDGE with a mirror image would be nearer to reality). MJKs worksheets http://www.quarter-wave.com/Models/MathCad_Models.html (http://www.quarter-wave.com/Models/MathCad_Models.html) are a much better way.
First I simulated (red) my H-frame from the same 60 cm distance as the measurement (black):
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/H_6_comp.gif)
Next I simulated the OB in the nearfield at 20 cm distance. The conformity is close enough:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_2_up_comp.gif)
For a comparison I simulated the OB at two distances. Light colour is for the simulation:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_2_12_up_comp.gif)
It´s very obvious: While at 20 cm simulation and measurement are rather close, the divergence at 120 cm distance is sincere. The later measurement is almost in the middle of the room, so accounting for floor and front wall only - as MJK does - can´t reflect reality completely. But neither can any other program.
A last simulation I want to show is the cone excursion of both baffles:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_H_excursion.gif)
The dotted blue line is for the infinite baffle.
My conclusion: MJKs worksheets will help you very much to design the best dipole for your needs, but the room will be a major factor in what you will hear in the sweet spot.
One day later:
This is how the MJK worksheet see the difference between the driver mounted low and high on the OB. The large dip at 430 Hz is the floor reflection for the driver mounted at 56 cm.
(http://rudolffinke.homepage.t-online.de/audio/Dipol/W250/Syscomp/OB_driv_height_comp.gif)
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Rudolf,
Extremly good and interesting comparisons. I was going to remark that your 120 cm measurements fall a bit off the line if
compared to MJK's Math-Cad sheet and also if compared to the 60 cm and 260 cm measurements for the plain OB.
In the 60 and the 260 cm measurements the response is flat (relatively at least) above 200-250 Hz up to the upper roll off as one would expect, while the 120 cm
result is behaving quite differently. That the results for the up and down placed units doesn't differ more is a bit surprising considering that you have
good help of the floor. Baffle dimensions can as I have put forward be quite small if floor reflection is accounted for.
However that the results with the 45x70 OB and the H-OB does'nt differ more is not so surprising as dimensions are fairly equal.
Also which perhaps has not been quite put forward is that the Visaton W 250 is quite a capable bass unit for OB use.
Another thought, with the help of Martin's models one could simulate the ideal OB bass unit. I wonder if someone has given that angle a thought.
I think such an excercise could qualify as serious scientific research. There will be some combinations of TSP-parameters that will give superior OB Bass result, and these will not only be dependent of Qts value. There is more to it ! :thumb:
/Erling
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Erling,
thanks for your friendly remarks. :) And yes, there are measurements that are not like expected, like that H-frame and OB comparison at 120 cm. The first two results in my last post make me even more confident, that sims with the MJK worksheets will deliver clearer results than that mess of reflections and room modes which I measure with JustOct.
With regard to the OB and H-frame comparison I expected a close race too, since the effective dipole radii would be roughly equal. What I still want to show is that you can get equal performance to a plain OB with much less visual impact. Your U-baffle does support that as well.
I see that we really are in the same boat when it comes to price-performance-ratios. :thumb: Those Visaton drivers are just basic drivers, but with reliable values. No quality outliers, no strange noise. Nevertheless I am on the verge of buying some Perless SLS drivers to replace the Visatons.
Rudolf
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I did another comparison between a plain baffle and a "tapered" H-frame:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/H%20frame%20SLS/H-frame%20SLS10.jpg)
The baffle is 80x30 cm with the wings base protruding 21 cm to the front and back. The baffle is tilted back 5°. Driver is a Peerless SLS 10. The camera perspective might suggest otherwise, but the baffle is rectangular with the wings perpendicular to it.
I measured the baffle without wings (black) first and then added the wings (red). Distance 1 m. The diagrams are smoothed 1/3 octave:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/H%20frame%20SLS/H%20frame%20SLS%2010%20wings.gif)
By and large I win about 6 dB by adding the wings, which is the same as adding a second SLS 10 at floor level.
I then turned the H-Frame 180° and measured the response at the back side. With the tilted baffle the wings inclose a slightly bigger volume in the back than in the front. So the back SPL (blue) is a bit more than the front radiation, but symmetrical enough for the planned operation up to 200 Hz:
(http://rudolffinke.homepage.t-online.de/audio/Dipol/H%20frame%20SLS/H%20frame%20SLS%2010%20wings%20f_r.gif)
Finally I want to build H-frames with equally tapered wings, but with a SLS 12 at the bottom, SLS 10 above and a 7" midrange with 1" tweeter on top, resulting in a tapered baffle too.
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Rudolf,
Interesting design and measurement. Am I right to conclude that the side panels are triangular with a base of (21+21+baffle thickness) cms and about 80 cm high ?
/Erling
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Rudolf,
Just a point of clarifications, the actual woofer implementation would be a pair of woofers mounted on your "tapered" H-frame, one firing forward and the other firing towards the rear.
If that the case then you would see the rear of one woofer facing you? The general appearance may not look too good.
I may be wrong if this the case please explain.
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Am I right to conclude that the side panels are triangular with a base of (21+21+baffle thickness) cms and about 80 cm high?
That´s exactly right, Erling. Base length is 44 cm total. This H-frame is just a test bed. Later I will cut off the upper 20 cm of the triangles and put in horizontal dividers between and above the SLS to see if that makes any difference (I believe the difference will be quite small).
The basic design is no invention of mine. I first saw it here:
http://www.diyaudio.com/forums/showthread.php?postid=752224#post752224 (http://www.diyaudio.com/forums/showthread.php?postid=752224#post752224)
(http://brainwatch.us/images/sym_h_frame_front.JPG)
I will taper the final baffle in the same way. In the end the midrange driver will see a smaller baffle than the bass drivers and no protruding wings to the sides.
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Just a point of clarifications, the actual woofer implementation would be a pair of woofers mounted on your "tapered" H-frame, one firing forward and the other firing towards the rear.
I may mount the lower woofer with the basket to the front, yes.
If that the case then you would see the rear of one woofer facing you? The general appearance may not look too good.
In that case I intend to experiment with some front cover. I´m not sure yet, whether that will add too much visual "volume" to the contraption. I will have to do it to find out. :)
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Rudolf,
I suppose you already have seen it otherwise you will be interested, a new MJK-study of OB, U- and H-frame performance:
http://www.quarter-wave.com/OBs/OB_Theory.html .
/Erling
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Erling,
I´m no spider! I don´t have my eyes in every direction. :green:
So thanks very much for guiding me to MJKs new study. Haven´t seen it before.
You may have noticed that I am sounding the trumpet for the H-frame for quite a while. So I´m really grateful to MJK that he is showing what can be achieved (or not) with U- and H-frames compared to pure OBs. The icing on the cake would have been a comparison of the polar diagrams for different frequencies.
We are never contend with what we get, ain´t we? :nono:
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For a biamp guy like myself, seeking to redesign my baffles for decreased floor space, and increased WAF, I found the articles very interesting, even though I am not the specific target market.
I suspect I will go with the U baffle, in order to hit the deeper bass, and the drop in efficiency can easily be made up with my sub amp.
Nice catch, and thanks for sharing!
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how could i have missed this thread? :)
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BTW, Rudolf, how are you liking the Peerless SLS 12"?
I'm thinking to use the same (a pair per side), but I also saw some nice visaton 12". No idea of price yet.
http://www.visaton.de/de/chassis_zubehoer/tiefton/w300s_8.html
and che cheaper one
http://www.visaton.de/de/chassis_zubehoer/tiefton/w300_8.html
What do you think?
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BTW, Rudolf, how are you liking the Peerless SLS 12"?
I have to admit that I still don´t use them in a permanent system because I´m sidetracked all the time. But from testing I know that they will do very well. Somehow the SLS seem to be the stamped frame drivers with the build quality of a good cast frame driver. Their venting system is light years ahead of those Visatons you are mentioning. The W300 does not even have venting to speak of. Xlin (8mm) is well ahead of the Visatons (5 mm) too. Depending on the Xover frequency you may want to damp the frame legs a bit.
If you look around you will see the SLS series used in dipoles all the time. I don´t remember a dipole project with the Visaton W300 series.
BTW: I am amazed how fast you have been moving from a "no compromise accepted" attitude to the lowlands of value drivers. :roll: :wink:. It´s a lot more fun around here.
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Somehow the SLS seem to be the stamped frame drivers with the build quality of a good cast frame driver. Their venting system is light years ahead of those Visatons you are mentioning. The W300 does not even have venting to speak of. Xlin (8mm) is well ahead of the Visatons (5 mm) too. Depending on the Xover frequency you may want to damp the frame legs a bit.
If you look around you will see the SLS series used in dipoles all the time. I don´t remember a dipole project with the Visaton W300 series.
BTW: I am amazed how fast you have been moving from a "no compromise accepted" attitude to the lowlands of value drivers. :roll: :wink:. It´s a lot more fun around here.
Budget issues :(
But I'm still trying to get an excellent sound. And I can always upgrade the drivers in the future or make something new.
I ran some simulations and I agree that those Visatons are totally inferior to the Peerless SLS.
What do you think instead of the Eminence Beta 12A2*?
I's really looking good in my sim.
Same cheap price, slightly higher SPL in my xbaffle sim.
*"The 12A-2 has more Xmax and is a better bass woofer."
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(http://i39.tinypic.com/5z1tec.png)
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What do you think instead of the Eminence Beta 12A2*?
I's really looking good in my sim.
Sorry, I don´t know any longer, what the actual boundary conditions of your project are. Baffle size, efficiency, other drivers? You seem to be fixed to max. efficiency? Or is it max absolute SPL? Could you give a brief summary, from where I could better judge, what the actual goals are?
Rudolf
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What do you think instead of the Eminence Beta 12A2*?
I's really looking good in my sim.
Sorry, I don´t know any longer, what the actual boundary conditions of your project are. Baffle size, efficiency, other drivers? You seem to be fixed to max. efficiency? Or is it max absolute SPL? Could you give a brief summary, from where I could better judge, what the actual goals are?
Rudolf
Yes, sure.
Bass reinforcement 30-100hz roughly. Boost @ 35-30hz and XO done with the reckhorn B1, then amped with an alesis ra300.
Baffle 30-35cm wide + wings (havent decided the exact size. In Xbaffle i put 60cm which equals to 30cm width + 15cm wings,but they probably will be longer but sloped). For the height I have no probs, depending on the drivers i can go between 100 and 130cm.
Up there will be either a fullranger or a mid + tweeter, powered by my F3.
The goal for the bass is neither efficiency nor max SPL, it's transparency and quickness to keep up with the upper range.
Forgot to say that the baffles will be pretty close to rear wall (about 60cm).
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Telstar,
I compared the following drivers:
Peerless SLS 12 (green)
Eminence Beta 12a 2 (blue)
Visaton W300 (red)
Visaton WHC 30 X (lilac)
(http://rudolffinke.homepage.t-online.de/audio/Dipol/H%20frame%20SLS/comparison.gif)
(http://rudolffinke.homepage.t-online.de/audio/Dipol/H%20frame%20SLS/Power.gif)
The Visaton drivers have been simulated from actual frequency range measurements, the Peerless and Eminence from TSP only. Data will be comparable only to ~300 Hz.
As you can see, the Peerless will give you the maximum SPL down to 30 Hz, the Eminence the least.
If the SLS is beyond your budget, the Visaton WHC 30 X would be a real bargain at 30 Euro from
http://www.conrad-int.com/websale7/VISATON-WHC-30-X--8-OHM-HIFI-TIEFT%d6NER.htm?Ctx=%7bver%2f7%2fver%7d%7bst%2f3eb%2fst%7d%7bcmd%2f0%2fcmd%7d%7bm%2fwebsale%2fm%7d%7bs%2fconrad%2dint%2fs%7d%7bl%2fint%2fl%7d%7bmi%2fSHOP%5fAREA%5f17478%5f1312034%2fmi%7d%7bpi%2f310669%2fpi%7d%7bpo%2f1%2fpo%7d%7bfc%2fx%2ffc%7d%7bp1%2f6a0a9453b4c8ea628dbd1d8d2e35393b%2fp1%7d%7bmd5%2ff34fc2f24e7f5b8fb015dcd424d0aebf%2fmd5%7d (http://www.conrad-int.com/websale7/VISATON-WHC-30-X--8-OHM-HIFI-TIEFT%d6NER.htm?Ctx=%7bver%2f7%2fver%7d%7bst%2f3eb%2fst%7d%7bcmd%2f0%2fcmd%7d%7bm%2fwebsale%2fm%7d%7bs%2fconrad%2dint%2fs%7d%7bl%2fint%2fl%7d%7bmi%2fSHOP%5fAREA%5f17478%5f1312034%2fmi%7d%7bpi%2f310669%2fpi%7d%7bpo%2f1%2fpo%7d%7bfc%2fx%2ffc%7d%7bp1%2f6a0a9453b4c8ea628dbd1d8d2e35393b%2fp1%7d%7bmd5%2ff34fc2f24e7f5b8fb015dcd424d0aebf%2fmd5%7d)
As I already mentioned, quality wise the SLS is in another league compared to the competitors. I don´t know of any comparable 12" driver <100 Euro that could keep up.
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Hi Rudolf,
I sent you an email.