Eva said:
Dear Eva,
thank for your kind response.
My believe is: a very good amp drives properly "any" real speaker out there.
Then there are only good amps that drive "almost all" the speakers.
And going on there are at the end bad amps that have serious problem to drive a lot of real speakers.
To clarify my point I had the opportunity to try a Krell KSA50 with my speakers and it drove them with an authority very impressive.
For the very first time I got that solid bass response I am looking for.
And this for the amp.
Talking of my speaker you very well say: "Drivers with such a high Qts are extremely easy to drive for any amplifier, as the impedance is high, but are indeed very hard to use in any configuration other than open or infinite baffles".
I am everything but an expert but I trust in your statement.
My point is: a very famous brand like Dynaudio that puts a driver like this in a speaker that is not open of infinite baffles makes a huge mistake, I would stress an unacceptable mistake for their consumers.
They designed and built a speaker that can be defined just a "wrong" speaker!
And these speakers were not cheap at all I would add.
I would say that after all even the driver im my opinion is "wrong" seeing that all the best woofers are a very low Qts.
Just look at the "rightly" famous and appreciated Scanspeak 18W/8545 that has a Qts 0.27 instead of the 0.835 of the Dynaudio.
Actually I understand that the more recent Dynaudio production has undergone to a series of upgrading in the power of the magnet in order to and with the result of lowering the Qts.
To end all these my maybe silly ramblings:
the Krell KSA50 has been a masterpiece of amp and is able to drive almost any speaker with impressive authority
my speakers are not a masterpiece and do need a masterpiece of an amp to give a just adequate sonic result.
Kind regards,
beppe
Bose(o) said:
Dear Mr. Bose,
you understand me perfectly. Thank you.
Nevertheless I would stress the fact that this kind of woofer would be difficult to drive "properly" for any power amp.
This is a "wrong" driver.
I mean, some drivers have reached a cult status on the basis of their mechanical/electrical properties.
Looking at the Qes of my woofer it is very poor meaning a very humble magnet.
Please just look at some JBL pro woofer.
Oh guys, what a huge magnet they have, even made out of particular material like Alnico !
Of course they are very expensive drivers but also Dynaudio are not given as a present.
Scanspeak are much better in my mind, for instance.
Some manufacturers then put "a patch" adding maybe another magnet glued to the existing one.
Please Sir. Can we design and build a driver rightly firstly?
I understand that the current Dynaudio production has addressed the magnet decreasing the Qts as a result (good move Dynaudio. Bravo!).
When I purchased these two pairs of similar speakers I was very ignorant.
And now I understand I paid for my ignorance.
As you very well understand a very good and authoritative power amp can mitigate with "its" high qualities the defects of the speaker.
But even the best amp in the world can trasform a toad in a prince.
That was a fairy tale I am afraid.
Thank you very much indeed for your extremely kind and valuable support.
Kind regards,
beppe
Another afterthought. I never used a Variovent, but I believe they used plastic open celled foam as the resistive element.
If these are older speakers, it is possible that the foam in the Variovent has deteriorated and is no longer doing its job.
Also Beppe, some people, who are not as discerning as you, like a boomy bass. And I suspect the speakers were designed for that market.
If these are older speakers, it is possible that the foam in the Variovent has deteriorated and is no longer doing its job.
Also Beppe, some people, who are not as discerning as you, like a boomy bass. And I suspect the speakers were designed for that market.
Hum, I never thought of material wear, good call curmudgeon. One can then consider that the T/S parameters may have changed in a non-preferrable way as well further causing more havoc to the audio reproduced.
Beppe, it's great that you've learned a lot! Which brings me to ask: Are you going to DIY something? Since you have a so-called reputable brand (This threa has opened my eyes in Dynaudio's direction) then they should have damn good resell, enough for you to afford a DIY project of some sort.
Beppe, it's great that you've learned a lot! Which brings me to ask: Are you going to DIY something? Since you have a so-called reputable brand (This threa has opened my eyes in Dynaudio's direction) then they should have damn good resell, enough for you to afford a DIY project of some sort.
Dear beppe,
Your Dynaudio 24w-75 has an EBP ratio of 30 units which is much lower from the limit of 50 for using it into a closed box.
It's x-max is 5.5 for a 9 incher which is also excellent for a closed box.
The Qts of 0.835 looks high but there is no problem.
When we fit the speaker into the box Qts is going for vacations and we have Qtc which is the Q of the speaker and box combination and is lower.
Lower Qtc means stiffer, detailed more controlled bass.
With the use of the Variovent the Qtc tends to lower even more, as previously noted by 'sreten'.
So if we want to benefit from the use of the closed box and the Variovent, we must design a speaker unit with a relatively high Qts.
Beside you cannot evaluate them from Qts and magnet size only. There is more: other parameters, materials used, intensions, the tradition of the company.
Also you can never cure problems in loudspeakers changing amplifiers.
Loudspeaker transforms electric currents into sound, it is a kind of creation.
Maybe you can imagine the loudspeaker as the actor/director combination when sources, amplifiers and currents is the text or senario.
Sorry but I am not convinced that there is a real problem here.
Regards.
fiak
Your Dynaudio 24w-75 has an EBP ratio of 30 units which is much lower from the limit of 50 for using it into a closed box.
It's x-max is 5.5 for a 9 incher which is also excellent for a closed box.
The Qts of 0.835 looks high but there is no problem.
When we fit the speaker into the box Qts is going for vacations and we have Qtc which is the Q of the speaker and box combination and is lower.
Lower Qtc means stiffer, detailed more controlled bass.
With the use of the Variovent the Qtc tends to lower even more, as previously noted by 'sreten'.
So if we want to benefit from the use of the closed box and the Variovent, we must design a speaker unit with a relatively high Qts.
Beside you cannot evaluate them from Qts and magnet size only. There is more: other parameters, materials used, intensions, the tradition of the company.
Also you can never cure problems in loudspeakers changing amplifiers.
Loudspeaker transforms electric currents into sound, it is a kind of creation.
Maybe you can imagine the loudspeaker as the actor/director combination when sources, amplifiers and currents is the text or senario.
Sorry but I am not convinced that there is a real problem here.
Regards.
fiak
I agree with fiak. There is no real problem here, it's just that speaker design is not affordable for everybody, as it requires a scientific background instead of a subjectivist tweaker background.
Somebody speaking about taming a high Qts driver with an "authoritary amplifier" is not likely to have the required physics and acoustics understanding to success at all (not to mention the lack of solid state electronics understading). There are methods for solving that problem, but they involve measuring, modelling and calculation only (no room for "authoritary amplifier" imaginative tweaker stuff).
If a speaker has inherently high Qts and resonates more than desirable in the lowest LF range, it will do that with *any* amplifier (unless you build a special one with negative output impedance at LF as i mentioned). However, Qb or Qtc may be reduced either with a "stuffed" lossy vent tuned near Fs (as it was pointed out) or with a conveniently big and stuffed lossy sealed box.
Somebody speaking about taming a high Qts driver with an "authoritary amplifier" is not likely to have the required physics and acoustics understanding to success at all (not to mention the lack of solid state electronics understading). There are methods for solving that problem, but they involve measuring, modelling and calculation only (no room for "authoritary amplifier" imaginative tweaker stuff).
If a speaker has inherently high Qts and resonates more than desirable in the lowest LF range, it will do that with *any* amplifier (unless you build a special one with negative output impedance at LF as i mentioned). However, Qb or Qtc may be reduced either with a "stuffed" lossy vent tuned near Fs (as it was pointed out) or with a conveniently big and stuffed lossy sealed box.
The observation that a more powerful amplifier produced the sound Beppe wanted may not agree with some person's understanding of theory. Nonetheless, it is the theoreticians' job to explain the observation. Since the only effect anyone could think of that might explain the satisfactory results with a different amplifier revolved around damping factor, that was explored in the thread above, not all of which every poster has read.
Alternative explanations, that match the observation would be very interesting.
LEAP's first pass utility indicated at best a mild peak in either vented or sealed box of optimal size, which this is not. Not a bad starting point for the discussion.
Alternative explanations, that match the observation would be very interesting.
LEAP's first pass utility indicated at best a mild peak in either vented or sealed box of optimal size, which this is not. Not a bad starting point for the discussion.
The observation is worthless when the observer is not objective (would you also want us to study claims about $3000 power cords? I use to have more interesting phenomena to research).
beppe61 said:
Hi,
there is a lot of opinion in this thread and not much real practical advice.
If the Morel drivers fit the cut-outs in your speakers I strongly recommend
that you fit these drivers, they will drastically change the bass performance.
You are lucky that an almost "perfect" driver exists to fit as a replacement.
The resultant new bass alignment will have far less upper bass so they will
become room gain friendly, consequently low bass will sound much better.
🙂/sreten.
Bose,... Yes boss...
Tinitus,
This is a magnetically shielded woofer, difficult if not impossible to add magnet. Will require new specifications evaluation.
Beside you just need moderate magnets for closed boxes.
Feyz,
You are about right. We can calculate Xmax by taking the Voice coil length, subtracting the air gap height and dividing by two. That makes 2.75, which is still acceptable because with an effective cone area of 220 cub.cm this is rather an 8incher.
Sreten,
All these for the future historians, because if I am not wrong our fellow member has bought two new pairs of company made loudspeakers.
These are not diy or any budget pieces where you can make alterations, they will loose their value.
I give up.
Tinitus,
This is a magnetically shielded woofer, difficult if not impossible to add magnet. Will require new specifications evaluation.
Beside you just need moderate magnets for closed boxes.
Feyz,
You are about right. We can calculate Xmax by taking the Voice coil length, subtracting the air gap height and dividing by two. That makes 2.75, which is still acceptable because with an effective cone area of 220 cub.cm this is rather an 8incher.
Sreten,
All these for the future historians, because if I am not wrong our fellow member has bought two new pairs of company made loudspeakers.
These are not diy or any budget pieces where you can make alterations, they will loose their value.
I give up.
Hi, not very helpfull i know, but I have a suspicion that this driver originally was made for a big 4-way system - I think in the old day they even had 5-way speakers
fiak said:
Hi,
Generally I would agree with you but for this scenario
if you read my posts you will see this is not the case.
🙂/sreten.
Curmudgeon said:
Dear Sir,
I think that the influence of Variovent is marginal after all.
My understanding after all these discussions is the drivers make a speaker in the end.
I am more and more convinced that these woofers should be replaced with others to save the rest, that is good indeed (I mean the dome drivers).
Maybe in the next future I will start modding the two ways model.
Thanks a lot and kind regards,
beppe
Bose(o) said:
Dear Mr. Bose,
more than about reselling them I am thinking about modding them.
The boxes are substantial and well built.
I think that chage a driver would be easier after all.
Thank you veyr much indeed.
Kind regards,
beppe
fiak said:Dear beppe,
Your Dynaudio 24w-75 has an EBP ratio of 30 units which is much lower from the limit of 50 for using it into a closed box.
...
Sorry but I am not convinced that there is a real problem here.
Regards.
fiak
Dear Mr. Fiak,
I think that a really good speaker should have two qualities:
1) good with a lot of different amps
2) should leave some "traces" in the audio world like the Dalquist DQ10, the AR10-p, etc.
For point 2) I have never found a review of these speakers, so they were and are nothing of remarkable.
Then I see that making a low Qts is expensive, difficult.
If some brands face all these problems a reason should be.
Don't you think so ?
And after all I believe in first impression and I remember that first impression was bad from the start.
With time I have discovered that I like powerful, fast and punching bass: qualities that these woofers fail to give me.
Thanks a lot and kind regards,
beppe
Eva said:
Thank you Miss.Eva,
1) you are very right. Speaker design is so difficult that even at Dynaudio they have not understood completelythe the principles behind it.
This is a wrong speaker and a wrong buy for the poor and not expert people like me. I was lucky not to buy it new !
2) I do not like "resonating" woofers at all. Do you like them?
Thank you sincerely.
Kind regards,
beppe
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