sreten said:
Hi, anyone interested in building open baffles would
be very interested in those dynaudio bass drivers.
Replacing the bass unit in the 3-way should be straightforward,
in the 2-way it would be more difficult because of the crossover.
/sreten.
Dear Mr. Sreten,
do you have any specific suggestion for the 3-way, that anyway I prefer between the two ?
The 3 way has the 24W75.
The driver should be much easier to drive (of course).
Thank you very much for your extremely kind and valuable help.
Kind regards,
beppe
I'm powering a set of speakers with a sensitivity around 88-90dB.
As far as power requirements and thiele small paramters go, you'll want to look at: Cms, SPL, and Re. There are of course more as was previously mentioned, but this is what I look at when comparing drivers initially. As in, when I am searching for 6.5" drivers, I will compare using those values and then go into finer details as I narrow the choice down to two or three drivers.
Cms usually noted in mm/N is the excursion per Newton (force from magnet). This is the suspension 'compliance' or in easier words, the amount that the cone moves given a set amount of force. Intuitively then, the higher the Cms the easier it would be to power a speaker and, the lower the Cms the harder it is to power the speaker to the same excursion.
SPL is usually noted in dB/V (decibels, a unit of loudness). SPL will desribe the loudness of a speaker given a reference voltage which is typically 1V or 2.83V. You can convert the voltage to W to get a better idea of the amount of power the speaker may require for a certain loudness. Of course, this is dependent on the impedance that the 'enclosure' represents to the driver.
Re, the DC resistance, or the only important resistance reading (Z is rough and designing with respect to Z [nominal resistance] is pointless or 'rough'). Chose Re as close as possible to the stable mode of the amplifier's output, this will optimise control and power transfer to the driver.
Enjoy!
As far as power requirements and thiele small paramters go, you'll want to look at: Cms, SPL, and Re. There are of course more as was previously mentioned, but this is what I look at when comparing drivers initially. As in, when I am searching for 6.5" drivers, I will compare using those values and then go into finer details as I narrow the choice down to two or three drivers.
Cms usually noted in mm/N is the excursion per Newton (force from magnet). This is the suspension 'compliance' or in easier words, the amount that the cone moves given a set amount of force. Intuitively then, the higher the Cms the easier it would be to power a speaker and, the lower the Cms the harder it is to power the speaker to the same excursion.
SPL is usually noted in dB/V (decibels, a unit of loudness). SPL will desribe the loudness of a speaker given a reference voltage which is typically 1V or 2.83V. You can convert the voltage to W to get a better idea of the amount of power the speaker may require for a certain loudness. Of course, this is dependent on the impedance that the 'enclosure' represents to the driver.
Re, the DC resistance, or the only important resistance reading (Z is rough and designing with respect to Z [nominal resistance] is pointless or 'rough'). Chose Re as close as possible to the stable mode of the amplifier's output, this will optimise control and power transfer to the driver.
Enjoy!
It sounds as if the speaker responds to higher current amplifiers because the larger amp is able to maintain the damping factor at higher currents, due to the lack of current limiting. Perhaps improving overall damping factor might help; the suggestions below may not help, but on the other hand are inexpensive and fairly easy, so are worth trying first.
1. Be sure your speaker cables are low resistance; larger diameter and shorter, unless they are already pretty big.
2. The woofer will have a series inductor to roll off its high end; lowering the DC resistance of the inductor, by replacing it with one of the same inductance but lower resistance might also help.
1. Be sure your speaker cables are low resistance; larger diameter and shorter, unless they are already pretty big.
2. The woofer will have a series inductor to roll off its high end; lowering the DC resistance of the inductor, by replacing it with one of the same inductance but lower resistance might also help.
Curmudgeon said:
Dear Sir,
thank you sincerely for your very valuable reply.
1) This has been exactly my own sensation when I had the opportunity to try the speakers with a high current amp.
The sound became very tight, powerful, fast and above all very enjoyable indeed.
So I know that the speakers can sound very well.
After all the distortion figures of the woofer are very impressive indeed and I have always found the sound very realistic and natural in tone.
These speakers do deserve a chance.
Moreover I am pretty sure that an amplification that does justice to these speakers should be also very good with a lot of other speakers.
2) Very interesting advice.
For point 1)
The connecting cables are already quite big in section.
I could do something with terminations instead.
They do not look high quality.
For point 2)
This is very interesting.
I have already heard about so called "zero-resistance" coils for crossovers.
I will try to find them here in Italy.
I sincerely hope to improve the global "dynamic" response of the system because, as maybe I have already said, I like very much the sound from the speakers for its realism.
Maybe I am influenced by the very low distortion figures I saw on the woofer's data sheet.
Thank you very much indeed for your extremely kind, friendly an very valuable support and advice.
Kind regards,
beppe
Lee1234 said:
Dear Mr.Lee,
thank you again for your kind and valuable reply.
Your amps are so much more powerful than mines.
I understand that these kind of drivers ask for power.
Nevertheless it seems to me that your words confirm the high quality of the drivers.
I will try to find a very strong amp (like those you mention) at a nice price.
I would like to stay with Dynaudio having heard that recently at BBC they have installed a lot of monitors from this Company.
Thank you very much again.
Kind regards,
beppe
beppe61 said:
Hi,
without specific details of your cabinet and new bass alignment required,
and as much detail as possible about the crossover is hard to be specific.
However something like the Seas CA22RNX (H1288) would probably work if
your cabinet is bass reflex. Minor mods to the crossover may be needed.
(Depends on if the crossover uses zobel driver compensation or not)
What budget is possible for each bass driver ?
/sreten.From my experience, a zobel is MUST when designing a passive cross-over. I remember that it was equivalent to buying a better amplifier, more control, tighter dynamics, more musical all at the same time. It required the purchase of my NAD too, finally, I speakers revealed the low quality of the Technics amp that I was using.
Back to the topic, if amplifier juice is all that you need and you HAVE heard your speakers sound better with an amplifier then I guess you should be buying an amplifier. If that's what you prefer of course. IIRC, you have an adcom and Adcom is supposed to outpace the NAD stuff. Anyway, have you looked at Behringer? My friend has their A500 (I think) and it's hooked up to the 901s, which, could use more power, but it's pretty damn good sounding for a pro audio amp.
Back to the topic, if amplifier juice is all that you need and you HAVE heard your speakers sound better with an amplifier then I guess you should be buying an amplifier. If that's what you prefer of course. IIRC, you have an adcom and Adcom is supposed to outpace the NAD stuff. Anyway, have you looked at Behringer? My friend has their A500 (I think) and it's hooked up to the 901s, which, could use more power, but it's pretty damn good sounding for a pro audio amp.
sreten said:
1) Hi, without specific details of your cabinet and new bass alignment required, and as much detail as possible about the crossover is hard to be specific.
2) However something like the Seas CA22RNX (H1288) would probably work if your cabinet is bass reflex.
Minor mods to the crossover may be needed.
(Depends on if the crossover uses zobel driver compensation or not)
3) What budget is possible for each bass driver ?
Dear Mr. Sreten,
1) I understand perfectly your point. As a first step I would like to try changing the inductor in series with the woofer with a low resistance type as Mr. Curmudgeon advises, so that the damping improves.
Presently is one of the main problems.
2) Thank you for your kind suggestion.
If i understand correctly this drive should be an easier load for the amp and also it has a lower Qts (a good thing in general).
I will try to draw the xover schema anyway.
3) I have not fixed any budget yet. I am trying to evaluate the cost of the modification.
I think that the woofers should be about 150$/each?
In this case a 400$ budget is the minimum required.
Thank you so much and kind regards,
beppe
Bose(o) said:
Dear Mr. Bose,
1) unfortunately this is out of my reach.
I have to study what a "zobel" is before.
2) Well let's say that I tried two little British monos able to source a peak current of almost 20A (nice little things indeed but very uncommon in the used market).
For the first time the speakers "sang" or "woke-up".
In particular the bass was very tight but also deep and powerful and transmitted the sense of rythm ala JBL, if I can use the paragon.
My Adcom gfa 545 1st series is not enough unfortunately.
3) I have heard of the A500 and the very positive review on the online mag "The Audio Critic".
I think that the 901s are a much easier load than my Dynaudio anyway.
There should be also the Behringer EP1500, a QSC clone, specified at about 250W/8 ohm and 400W/4 ohm, maybe a better (more powerful choice).
The EP1500 has the problem of noisy fans.
I wonder if the A500 can provide enough current.
Thank you very much indeed.
Kind regards,
beppe
Bose(o) said:
Hi,
this is a very simplistic viewpoint and simply not true for all cases.
There are cases where they help a great deal, e.g. second
order serial crossovers, and other cases where they are a
pointless addition, e.g. second order parallel crossovers.
If B61s crossovers do not have Zobels for the drivers (I suspect
that they don't) then adding them would be completely wrong.
/sreten.
sreten said:
Hi,
IMO changing the inductor will be a waste of time and money.
Please give details of the speaker cabinet, i.e. its internal
volume and if it is reflexed the dimensions of the port.
I need this to suggest suitable bass driovers.
Dear Mr. Sreten,
Thank you for your reply again.
I hope that these infos could be useful.
Drivers complement of the 3 way speaker is:
24W75 + D52 + D21
of the 2 way
23W75 + D28
The internal dimension (net) are:
24*25*45 cm for the 2 ways
27*25*55 cm for the 3 ways
both have a variovent (10cm diameter) on the upper part in the back.
They are pretty full of dumping material similar to glass wool.
I could not examine the x-over beacuse is bolted in the back.
Thank you very much.
Kind regards,
beppe
sreten said:Hi,
Lets stop beating about the bush.
The plots attached are for 60 litre sealed and reflexed.
THANK YOU Mr. Sreten!
Exceptionally interesting software.
Unfortunately I am absolutely ignorant about these kind of emulation softwares.
Did you simulate the behaviour of the 24W75 ?
Now, I see you have used a 60l volume for simulation.
This is much bigger than the actual volume of my two speakers!
Do you mean that the boxes are too small to give an adequate bass response?
This is extremely interesting.
What kind of response I can expect from my two present speakers?
Thank you very much again.
Kind regards,
beppe
My honest opinion, if your satisfied with the way they sound with a powerfull amplifier, your best bet is to get a good amplifier.
The woofer from the spec page you had linked at the first post of the thread shows a small Xmax value (for todays standards.) A bigger box or a reflex box will probably give trouble with driver going over xmax frequently. The driver seems to be designed for a sealed box anyways from the specs. So playing with volume or changing it to reflex box is likely to cause more trouble. I also wouldn't recommend replacing it with another woofer if you don't have the tools to do some measurements and some skill with xovers, which appears you don't.
If these speakers are brand name Dynaudio speakers, meaning the boxes are Dynaudio as well with the brand on it etc, your other option is to sell them and either try a good speaker kit with a well reputation for good controlled bass response, or try another commercial speaker, may be a used one if price is an issue. If the speakers you have were DIY, then sell the drivers individually, you are still likely to get good money on them, including the bass drivers.
But again your best bet and most convenient option IMO is to get the amplifier which makes them sound good. But if you want to get into the hobby of DIY speakers and to have fun for a while with trying different things, that's a different issue.
The woofer from the spec page you had linked at the first post of the thread shows a small Xmax value (for todays standards.) A bigger box or a reflex box will probably give trouble with driver going over xmax frequently. The driver seems to be designed for a sealed box anyways from the specs. So playing with volume or changing it to reflex box is likely to cause more trouble. I also wouldn't recommend replacing it with another woofer if you don't have the tools to do some measurements and some skill with xovers, which appears you don't.
If these speakers are brand name Dynaudio speakers, meaning the boxes are Dynaudio as well with the brand on it etc, your other option is to sell them and either try a good speaker kit with a well reputation for good controlled bass response, or try another commercial speaker, may be a used one if price is an issue. If the speakers you have were DIY, then sell the drivers individually, you are still likely to get good money on them, including the bass drivers.
But again your best bet and most convenient option IMO is to get the amplifier which makes them sound good. But if you want to get into the hobby of DIY speakers and to have fun for a while with trying different things, that's a different issue.
Feyz said:
Dear Mr. Feyz,
thanks for your appreciated reply.
1) This is the case. I liked my speakers with a more powerful amp. Any suggestion about suitable high-current amps?
2) Interesting. Thanks.
3) Would it be beneficial to close the hole on the rear of the variovents then? how?
4) I do not have neither tools or expertise actually.
5) "try a good speaker kit with a well reputation for good controlled bass response".
Any suggestion? maybe a 2 way should suffice as my room is not that big.
Thank you very much indeed.
Kind regards,
beppe
Hi,
your 3 way box appears to be around 37 litres.
I'm not sure how well the variovents work.
They are a form of aperiodic loading, I don't know how to sim it.
A Q of 1.56 in a sealed 37 litres is a very bad place to start from.
As I said earlier a low DCR inductor is not going to help.
/sreten.
your 3 way box appears to be around 37 litres.
I'm not sure how well the variovents work.
They are a form of aperiodic loading, I don't know how to sim it.
A Q of 1.56 in a sealed 37 litres is a very bad place to start from.
As I said earlier a low DCR inductor is not going to help.
/sreten.Attachments
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