I don't have words to thank you for all your help. I am learning a lot with your explanations and also having the possibility of building the speakers with a solid help. As I said before, I had the idea that designing a two way speaker it was better to crossover it as high as possible to limit the amount of mid range going to the tweeter. I see your experience is different for home use. In any case, playing with the crossover, we can change the way the drivers are set up, but we need to have range with both drivers. I was looking to Part Express and found they have a line of speakers, Dayton Audio, where they have woofers going as high as 7000 Hz. They aren't very expensive but I don't have any idea about the quality of those drivers. I think that having a woofer that responds as high as 4K Hz or more and a tweeter that can be set as low as 2k Hz, we have enough range to change the crossover in case it be necessary. I mean more possibility of adjusting the design after listening to it. However, if the selected woofer has a top of 2K Hz, it forces you to crossover at that point or lower and there is not margin to play. Anyway, I am very excited and hoping to begin the project soon.
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People speak good about Dayton here :
Dayton drivers vs. ScanSpeak and Seas?
What do you think of this one ?? It responds to 4000 Hz
Dayton Audio DS215-8 8" Designer Series Woofer Speaker
Dayton drivers vs. ScanSpeak and Seas?
What do you think of this one ?? It responds to 4000 Hz
Dayton Audio DS215-8 8" Designer Series Woofer Speaker
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This speaker seems to have reviewed well but I have some concerns about it. The plots have been smoothed, it always a bit misleading to compair unsmoothed plots with smoothed ones. There could be short peaks in the response that we cant see and the peaks we can see might be worse for short frequecy spans
The cone break up at 1khz looks like it is resonating quite strongly, notice the disturbance in the impedance plot at the same frequency. This is indicative of resonance in the cone and thus energy storage causing poor transient response. You always get a bit of this but it seems quite high in this driver. It might sound quite musical depending on the behaviour of the resonance but it is not accurate and usually smears the image slightly. See the regions I have circled in the plots.
If it is especially cheap it might be worth putting up with these faults and designing to minimise the effects but they would be quite hard to mask in the crossover.
The cone break up at 1khz looks like it is resonating quite strongly, notice the disturbance in the impedance plot at the same frequency. This is indicative of resonance in the cone and thus energy storage causing poor transient response. You always get a bit of this but it seems quite high in this driver. It might sound quite musical depending on the behaviour of the resonance but it is not accurate and usually smears the image slightly. See the regions I have circled in the plots.
If it is especially cheap it might be worth putting up with these faults and designing to minimise the effects but they would be quite hard to mask in the crossover.
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The good reviews and technical data called my attention but I don't have the resources neither knowledge to judge it right. The price is half of the Scanspeak. There are other Dayton drivers with good reviews. I would like to find a woofer with a frequency response higher than 2000 Hz, no matter if the crossover be designed to less than 2000 Hz. I would like to feel safe in case a live test doesn't sound the way I like. Having a woofer with more mid-range allow to increase the crossover point and to release the tweeter in any case. Maybe it isn't necessary but the possibility is there.
This is the other option I found with Dayton. But, again, I don't know how good it may be. The price is $30.00 less than the Scanspeak.
Dayton Audio RS225P-8A 8" Reference Paper Woofer 8 Ohm
The reviews are good and I like the paper cone. This belongs to its reference line.
Dayton Audio RS225P-8A 8" Reference Paper Woofer 8 Ohm
The reviews are good and I like the paper cone. This belongs to its reference line.
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I understand the low Qms doesn't have the last word. Qts is more important according to some articles I read. For instance one of them says it :
Qms will tend not to make much of a difference, since the forces arising from mechanical properties o the cone and suspension will be small compared to the loading caused by a nice enclosure and by the electrical properties.
Reading this old discussion, I am still confused :
The significance of high Qms..?
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Of the two I think the DS215-8 would probably be easier to work with as its response is more controlled over a larger frequency range. However neither of these speakers has 60deg of axis plots (They stop a 45deg) so their off axis response could become very poor the further out you go. (the scan speak included 60deg)
Whilst they do offer extended on axis response the off axis response of any 8 inch driver becomes problematic for good power response in the room as you go over 2kHz. It why most manufacturers of 2 way speakers now use 6 - 6.5 inch drivers rather than 8 inch.
Whilst they do offer extended on axis response the off axis response of any 8 inch driver becomes problematic for good power response in the room as you go over 2kHz. It why most manufacturers of 2 way speakers now use 6 - 6.5 inch drivers rather than 8 inch.
If I am understanding all this right, high Qms = softer surround and less rigid, and low Qms = harder surround material and more rigid cone (or spider) So, some people favor one, and other the opposite. My Paradigm Studio 100 V2, that were top of the line, have rigid woofers. The surround material is rigid and doesn't allow the cone moves easily. I tested them with a Classe power amp with a very high damping factor, even driven with this amp, the Paradigm's woofers didn't move a lot (even at high volume) One observation I can say is lower line Paradigm's models didn't have woofers with hard surround materials. So, Paradigm designers could have a good reason to chose low Qms drivers to build their top of the line speakers with them. I am sorry if what I am reasoning isn't correct. I am learning.!
A low Qms means the driver is mechanically providing the necessary damping. Most speakers today instead depend on the amplifier to supply the damping (Qes). One cannot make any judgements unless the entire system is considered. In the end the total of th emechanical damping & the electrical damping is what is important (Qt)
One thing a low Qms driver allows is an amplifier with higher output impedance to work well.
dave
One thing a low Qms driver allows is an amplifier with higher output impedance to work well.
dave
Yes, that is what I understand with my poor knowledge. The driver is "playing the role" of a high damping factor amplifier, or at least, helping the poor damping of most modern home receivers and integrated to control the sound. Not sure if I am right.!
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Most modern SS amplifiers, including commercial receievers & integrated amps, have low enuff output impedance that they are essentially the same (ie damping factor of something like 20+ are essentially the same).
A high damping factor is in no way a measure ofamplifier quality, just a clue as to which speakers will work best with it.
dave
A high damping factor is in no way a measure ofamplifier quality, just a clue as to which speakers will work best with it.
dave
Yes, there are speakers demanding a high damping factor amplifier. It all depends of the drivers. However, I understand a high damping factor is a resource that offer better speaker control, a better way to drive the speakers without distorting.
If you can afford it I think it will provide a better solution than either of the Dayton drivers. However if you cant afford it or would prefer not to spend that much money the Dayton clearly can sound good at least to the people reviewing it.
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