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Multi-Way Conventional loudspeakers with crossovers

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Old 9th April 2006, 06:44 PM   #21
beppe61 is offline beppe61  Italy
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Location: torino
Quote:
Originally posted by sreten

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
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Old 9th April 2006, 11:10 PM   #22
Lee1234 is offline Lee1234  United States
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Perhaps the bias on your Adcom is low. If the heatsinks are kinda cool then you have some room to push the amp a little more into class A.It sure helped my Adcoms sound better.Bass was not so good and the highs were very bad.
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Old 9th April 2006, 11:17 PM   #23
Lee1234 is offline Lee1234  United States
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I have Adcom 5300, Hafler XL600, DIY Krells from these fine forums.Upping your power supply capacitance and also bypassing with film caps helps.Course if your capacitors get too large then your rectifer is in danger unless you have something to minimize turn on surge.
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Old 9th April 2006, 11:42 PM   #24
Bose(o) is offline Bose(o)  Canada
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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!
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Old 10th April 2006, 02:00 AM   #25
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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.
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Old 10th April 2006, 07:18 AM   #26
beppe61 is offline beppe61  Italy
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Quote:
Originally posted by Curmudgeon

1) 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.
2) 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.
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
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Old 10th April 2006, 07:30 AM   #27
beppe61 is offline beppe61  Italy
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Quote:
Originally posted by Lee1234

I have Adcom 5300, Hafler XL600, DIY Krells from these fine forums.
Upping your power supply capacitance and also bypassing with film caps helps.
Course if your capacitors get too large then your rectifer is in danger unless you have something to minimize turn on surge.
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
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Old 10th April 2006, 02:21 PM   #28
sreten is offline sreten  United Kingdom
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Quote:
Originally posted by beppe61


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
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.
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Old 10th April 2006, 04:30 PM   #29
Bose(o) is offline Bose(o)  Canada
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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.
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Old 10th April 2006, 06:05 PM   #30
beppe61 is offline beppe61  Italy
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Join Date: Feb 2005
Location: torino
Quote:
Originally posted by sreten

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 ?
/sreten.
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
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