I will advice you not to mess around with your Dynaudio speakers
I dont think you will have much succes with modding them - its way too complex - and they will loose their value
If you think of OpenBaffle there are better options, and cost even less
But you seem to like a tight and clear detailed bass - well here crossovers often muddies things, and a very good fullrange solution steers clear of all this fuzz
I dont think you will have much succes with modding them - its way too complex - and they will loose their value
If you think of OpenBaffle there are better options, and cost even less
But you seem to like a tight and clear detailed bass - well here crossovers often muddies things, and a very good fullrange solution steers clear of all this fuzz
tinitus said:
Hi Tinitus,
1) you are very right, expecially about resell value.
Instead of modding I would have said to design again the speakers keeping the boxes and the dome drivers that I really like.
There is indeed a potential in these speakers.
However if you look in the web you can see a lot of suggestions about equipment modding, even on classic speakers.
A friend of mine has a McIntosh pair (do not remember the model).
A designer modded their xovers an the speakers gained in efficiency and transparency.
2) so no openbaffle design.
3) Definitely yes. I like a bass that is thight and clear.
A "snapping" bass.
It is very important to me that ability to transmit the sense of the rythm.
And moreover I do not like any compression of dynamic peaks.
Thank you very much indeed.
Kind regards,
beppe
sreten said:
Seems to be "way too complex" for you to understand I know what I'm talking about.
The simplest ( so probably best ) solution is fitting suitable new bass drivers.
The process of doing this is very straightforward if you have the technical details.
/sreten.
Dear Mr. Sreten,
maybe I have wrongly understood your advice, but is it not just a problem of finding a woofer with the same impedance, sensitivity, mounting cutout and, of course, a lower Qts?
All considered I deem it an extremely sensible solution.
In this way I could save the boxes, the tweeters and the xover.
Thank you so much again for your valuable advice about this option.
Kind regards,
beppe
beppe61 said:
All the drivers parameters much be suitable, (mainly Re,Le,Qts, Fs,Vas)
The Morel unit is very near ideal (if it fits).
Details of the crossover for the bass unit in the 3-way would help.
The Morel unit might work well in the 2-way if a Zobel is used.
Again crossover details would help.
As I said before you could get the Morel's if they should work in the 3-way.
You could then see how well they worked in the 2-way.
/sreten.
Hi Beppe,
It's been some time since I looked at Dynaudio woofers, but my impression of them from years ago was that they did not use enough magnet in most of them. Also, they did not offer much Xmax but clearly worked reasonably well, far beyond their linear Xmax. Something to keep in mind with a weak motor is that, all things being equal - mainly cone mass, the efficiency is lower. It seems that they compensated for this by having large voice coils to handle the power of a larger amp. I believe that they were shooting for a driver optimized for a fairly high Qtc, say .8 to 1.0, closed box system which has some interesting properties. The slight peaking above resonance helps to compensate for baffle step. The higher Q provides more output at Fc than the same driver with more damping. There are a few Dynaudio drivers that have stronger motors with more typical characteristics, the 21W54 for example as used in the early Wilson Puppy woofer. These woofers work well beyond their theoretical Xmax - very interesting.
It is an interesting property of second order systems that the Q is the relative gain at Fc:
Qtc Gain
1.0 0dB
.7 - 3dB
.5 -6dB
The low Q=.5 system will take four times the power to provide the same output at Fc as the Q=1 system.
However, most if not all of the Dynaudio drivers would require a large box when used in a sealed configuration, and this is probably why they use a variovent. Interesting that the driver Q suggests closed box, but their moving mass and Xmax do not since most closed box drivers have high moving mass and long Xmax.
One mod that you might try is to seal off the variovent (from inside the box), then use a line level Linkwitz Transform to shift the system to a lower Q system with deeper extension. I'd shoot for a transformed system with Fc=40 and Qtc=.8. Remember you must have enough power to handle the boost EQ:
http://www.linkwitzlab.com/filters.htm#9
However, if you really were satisfied with a high end amp, I'd say that the problem is power and current. Try a high power amp that can provide high current such as the bigger Adcoms. Try 200W/ch. This is supported by the fact that the drivers are less efficient. The bigger high current amps will get you to a listening level where your higher up on the equal-loudness contours and make what bass your getting more effective. I cannot stress how important it is to have enough power. You might also experiment with less stuffing, try just lining the walls, then increase as needed.
I've been meaning to write more about aperiodic systems for some time now.
Dick Pierce does a fine job here:
...a variovent can be accurately modeled using a standard vented model (4th order) with the following adjustments:
1. Since the vent diameter is relatively large and the vent length essentially the thickness of the panel it's mounted in, the actual vent mass is quite low, that results in a box resonance which is much higher than would be considered reasonable for a vented system, which means that a system aligned with such a port would indeed have a very strange response, if it were not for the fact that:
2. With the damping in the vent, the port losses are extremely high, the resulting Qp is VERY low (around 1-2 max), and thus the action of the port at box resonance (at the high frequency it has) is significantly attenuated to the point where the contribution to the system's total volume velocity is essentially attenuated to insignificance.
The result is a vented system with a high Fb that has a very low Qb. Such systems, while still technically 4th order, approach 2nd order behaviour at and below resonance for a significant range.
What advantage does this have? Well, with normal woofers, it's not dear. It has no efficiency advantage over properly designed closed boxes, it does not have the bandwidth or efficiency advantages of lower-loss vented systems. It might have an advantage when you are forced to use a high-resonance, high Qts woofer (just like some of the woofers Dynaudio makes, for example).
But, magic it is not.
Dick Pierce
Loudspeaker and Software Consulting
17 Sartelle Street Pepperell, MA 01463
-----------------------------
Pete B.
It's been some time since I looked at Dynaudio woofers, but my impression of them from years ago was that they did not use enough magnet in most of them. Also, they did not offer much Xmax but clearly worked reasonably well, far beyond their linear Xmax. Something to keep in mind with a weak motor is that, all things being equal - mainly cone mass, the efficiency is lower. It seems that they compensated for this by having large voice coils to handle the power of a larger amp. I believe that they were shooting for a driver optimized for a fairly high Qtc, say .8 to 1.0, closed box system which has some interesting properties. The slight peaking above resonance helps to compensate for baffle step. The higher Q provides more output at Fc than the same driver with more damping. There are a few Dynaudio drivers that have stronger motors with more typical characteristics, the 21W54 for example as used in the early Wilson Puppy woofer. These woofers work well beyond their theoretical Xmax - very interesting.
It is an interesting property of second order systems that the Q is the relative gain at Fc:
Qtc Gain
1.0 0dB
.7 - 3dB
.5 -6dB
The low Q=.5 system will take four times the power to provide the same output at Fc as the Q=1 system.
However, most if not all of the Dynaudio drivers would require a large box when used in a sealed configuration, and this is probably why they use a variovent. Interesting that the driver Q suggests closed box, but their moving mass and Xmax do not since most closed box drivers have high moving mass and long Xmax.
One mod that you might try is to seal off the variovent (from inside the box), then use a line level Linkwitz Transform to shift the system to a lower Q system with deeper extension. I'd shoot for a transformed system with Fc=40 and Qtc=.8. Remember you must have enough power to handle the boost EQ:
http://www.linkwitzlab.com/filters.htm#9
However, if you really were satisfied with a high end amp, I'd say that the problem is power and current. Try a high power amp that can provide high current such as the bigger Adcoms. Try 200W/ch. This is supported by the fact that the drivers are less efficient. The bigger high current amps will get you to a listening level where your higher up on the equal-loudness contours and make what bass your getting more effective. I cannot stress how important it is to have enough power. You might also experiment with less stuffing, try just lining the walls, then increase as needed.
I've been meaning to write more about aperiodic systems for some time now.
Dick Pierce does a fine job here:
...a variovent can be accurately modeled using a standard vented model (4th order) with the following adjustments:
1. Since the vent diameter is relatively large and the vent length essentially the thickness of the panel it's mounted in, the actual vent mass is quite low, that results in a box resonance which is much higher than would be considered reasonable for a vented system, which means that a system aligned with such a port would indeed have a very strange response, if it were not for the fact that:
2. With the damping in the vent, the port losses are extremely high, the resulting Qp is VERY low (around 1-2 max), and thus the action of the port at box resonance (at the high frequency it has) is significantly attenuated to the point where the contribution to the system's total volume velocity is essentially attenuated to insignificance.
The result is a vented system with a high Fb that has a very low Qb. Such systems, while still technically 4th order, approach 2nd order behaviour at and below resonance for a significant range.
What advantage does this have? Well, with normal woofers, it's not dear. It has no efficiency advantage over properly designed closed boxes, it does not have the bandwidth or efficiency advantages of lower-loss vented systems. It might have an advantage when you are forced to use a high-resonance, high Qts woofer (just like some of the woofers Dynaudio makes, for example).
But, magic it is not.
Dick Pierce
Loudspeaker and Software Consulting
17 Sartelle Street Pepperell, MA 01463
-----------------------------
Pete B.
beppe61 said:
PB2 said:
Dear Mr. Pete,
thank you so much for your very appreciated advice.
I am afraid a lot of the talk is just beyond my ability to understand.
Anyway I will study your statements very deeply before undertaking any action.
Nevertheless I think that the need to rely on very powerful power amps speakes against the Dynaudio woofers.
If I understand well your position confirms the opinion that the woofers' magnets are undersized.
Actually more recent woofers from Dynaudio sport bigger magnets.
Speaking of Qes I see a 1.11 for Dynaudio 24W75 and a 0.30 for the Scanspeak 18W/8545.
Instead Qms is 3.37 against 2.30.
On this basis I wonder from where comes the high reputation of the drivers of the brand.
Maybe the dome drivers are an entirely different matter.
Actually I like them a lot indeed.
Thank you very much indeed.
Kind regards,
beppe
Dear beppe,
Here is a project, which is I think is what you need, as life is short.
You must make or have somebody do it for you, a cabin with internal volume of 70 to 90 Lts, the bigger the better, with one or two PVC tubes for bass-reflex.
You can use the units, as well as, their cross-over from the three way loudspeaker.
You can make one and if you like it, you can then make the second.
If is difficult for you to remove the cross-over, leave it inside the Dynas and make extension cables. At the back of the new speaker, install three pairs of sockets for the drivers.
Try not to destroy or alter anything on the Dynas, as you will appreciate them in the future. Especially the arrangement of the dumping material is very critical for them.
Make the new one by at least 18mm MDF and cover at least half of the inside walls, one of the opposed, by around 4cm of dumping material. You can add some bracing, i.e. two wood sticks, say 4by4cm, at the two vertical walls.
You can see below the expected response, at the low end.
Please tell me if you are interested, as well as the volume, to post you the final details.
Regards.
fiak
Here is a project, which is I think is what you need, as life is short.
You must make or have somebody do it for you, a cabin with internal volume of 70 to 90 Lts, the bigger the better, with one or two PVC tubes for bass-reflex.
You can use the units, as well as, their cross-over from the three way loudspeaker.
You can make one and if you like it, you can then make the second.
If is difficult for you to remove the cross-over, leave it inside the Dynas and make extension cables. At the back of the new speaker, install three pairs of sockets for the drivers.
Try not to destroy or alter anything on the Dynas, as you will appreciate them in the future. Especially the arrangement of the dumping material is very critical for them.
Make the new one by at least 18mm MDF and cover at least half of the inside walls, one of the opposed, by around 4cm of dumping material. You can add some bracing, i.e. two wood sticks, say 4by4cm, at the two vertical walls.
You can see below the expected response, at the low end.
Please tell me if you are interested, as well as the volume, to post you the final details.
Regards.
fiak
Your welcome Beppe,
Wanted to mention that I heard Mark Levinson 3-way speakers (Cello, IIRC) based on all Dynaudio drivers about 10 years ago at a show. They were the Stradivari Legend if I remember correctly:
http://www.marklev.com/cello/img/legend_pp.jpg
It was a mighty impressive demo, the bass from that pair of 12" woofers shook the room and hit you in the chest. I believe that they were sealed with dome mid and tweeters. They probably had serious power to drive the systems, and I believe there was a Cello Palette for EQ. There might be hope for your speakers.
Pete B.
Wanted to mention that I heard Mark Levinson 3-way speakers (Cello, IIRC) based on all Dynaudio drivers about 10 years ago at a show. They were the Stradivari Legend if I remember correctly:
http://www.marklev.com/cello/img/legend_pp.jpg
It was a mighty impressive demo, the bass from that pair of 12" woofers shook the room and hit you in the chest. I believe that they were sealed with dome mid and tweeters. They probably had serious power to drive the systems, and I believe there was a Cello Palette for EQ. There might be hope for your speakers.
Pete B.
beppe61 said:
PB2 said:
Dear Mr. Pete,
please excuse my belated reply.
I had a look at the Cello website and found info about the discontinued (?) Stradivari line.
Very fine speakers indeed. And they seemed to use all Dynaudio drivers actually.
As you say these drivers (and woofers expecially) need very high power to deliver good sound.
Honestly I have to say that I appreciate their accuracy of tones, very natural and realistic, maybe due to a very low distortion ?
As I said in two occasions I heard them sound just fine, with high-current amps.
You talk about two 12" woofers per speaker.
Maybe those have better S-T parameters than mines.
By the way I found these data for a 12" woofer from Dynaudio:
DYNAUDIO 30W100
8Ohm
Qts 0.619
Fs 24 Hz
Vas 269 liters
Thank you very much again.
Kind regards,
beppe
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