Hello all,
I decided to hold of on my clonus faber project, and can honestly say I am glad I did. The amount of knowledge I've accumulated here in the time since has drastically changed my direction. Although I have come to another difficult position, I have a general outline of what I would like to build over the summer break but I would appreciate some additional input.
The driver layout will be an exact match of the Veritas Elevation 3 seen here:
The cabinet is similar as well although I have exchanged curved sides for an angular hourglass shape, the lower woofer section will also have a modest angle to orient the driver a little more on axis with the listening position. If not to the aid of acoustics, aesthetics will surely benifit greatly.
My driver selection has led me to a vented Eton 8-800 in the 34 liter lower section tuned to 37Hz via 3" tubing to minimize compression. The bass section will be crossed to the sealed upper module at 200Hz via 4th order active filter. The upper half will house the mid and a Scan Speak 9500. Here is my problem, typical to say the least, what mid to use?
I have narrowed my candidates at the moment to the Eton 7-360 and the Vifa PL18, both 7" drivers. Both were chosen on their merit as very smooth performers out to 4-5Khz, a higher than normal crossover frequency is the ultimate goal here. Of course, polar patterns force my hand at 3K with these woofers. I was thinking 2nd order on the Eton for a predicted summed 4th order slope, then a 4th order on the tweeter and a reverse polarity wiring to bring the two back in phase. The Vifa would simplify matters to 4th order on both the mid and tweeter due to its extended response to 6K. The Eton's cone seems stiffer to me, which I would consider highly desireable, although it doesn't exhibit any ringing which throws me for a loop... is it really stiffer or just well damped? On the other side, the Vifa has a much flatter and extended response curve and is half the price of the Eton.
So ladies and gents, what would you choose? Just to recap, all crossover points will be active and the whole system triamped, 100 watts to each driver via an Anthem PVA-7. Room will be 12 x 14 with hard floors, goals are clarity and accurate image placement while retaining ability to reproduce sustained 110Db's full range with various program music.
I decided to hold of on my clonus faber project, and can honestly say I am glad I did. The amount of knowledge I've accumulated here in the time since has drastically changed my direction. Although I have come to another difficult position, I have a general outline of what I would like to build over the summer break but I would appreciate some additional input.
The driver layout will be an exact match of the Veritas Elevation 3 seen here:
An externally hosted image should be here but it was not working when we last tested it.
The cabinet is similar as well although I have exchanged curved sides for an angular hourglass shape, the lower woofer section will also have a modest angle to orient the driver a little more on axis with the listening position. If not to the aid of acoustics, aesthetics will surely benifit greatly.
My driver selection has led me to a vented Eton 8-800 in the 34 liter lower section tuned to 37Hz via 3" tubing to minimize compression. The bass section will be crossed to the sealed upper module at 200Hz via 4th order active filter. The upper half will house the mid and a Scan Speak 9500. Here is my problem, typical to say the least, what mid to use?
I have narrowed my candidates at the moment to the Eton 7-360 and the Vifa PL18, both 7" drivers. Both were chosen on their merit as very smooth performers out to 4-5Khz, a higher than normal crossover frequency is the ultimate goal here. Of course, polar patterns force my hand at 3K with these woofers. I was thinking 2nd order on the Eton for a predicted summed 4th order slope, then a 4th order on the tweeter and a reverse polarity wiring to bring the two back in phase. The Vifa would simplify matters to 4th order on both the mid and tweeter due to its extended response to 6K. The Eton's cone seems stiffer to me, which I would consider highly desireable, although it doesn't exhibit any ringing which throws me for a loop... is it really stiffer or just well damped? On the other side, the Vifa has a much flatter and extended response curve and is half the price of the Eton.
So ladies and gents, what would you choose? Just to recap, all crossover points will be active and the whole system triamped, 100 watts to each driver via an Anthem PVA-7. Room will be 12 x 14 with hard floors, goals are clarity and accurate image placement while retaining ability to reproduce sustained 110Db's full range with various program music.
I am attempting to create an unusual shape along with a good speaker, so the long and short of it is that the visual dictated the distance.
If Dickason was correct though, at 200Hz, the distance shouldn't matter as it is significantly less than one wavelength at that frequency. My current drawing puts the center of the bass driver 32" from the center of the mid/tweet module. Shouldn't have problems until 400Hz, a full octave above XO. I'm hoping it will help to minimize any anomalies it is sure to introduce. I know I'm going to pay a price for the distance, but I just am not sure what that is going to be right now.
If Dickason was correct though, at 200Hz, the distance shouldn't matter as it is significantly less than one wavelength at that frequency. My current drawing puts the center of the bass driver 32" from the center of the mid/tweet module. Shouldn't have problems until 400Hz, a full octave above XO. I'm hoping it will help to minimize any anomalies it is sure to introduce. I know I'm going to pay a price for the distance, but I just am not sure what that is going to be right now.
Any recommendation for mids in that class? Seems most of the Danish entries fall short on the efficiency criterion. Also, the step down to 5" sizes, I am concerned that this will give way to nonlinearity problems later on when I ask this system to produce Dave Matthew's Band at 110 decibels for the entire Cd. I honestly do not believe they will handle the power, perhaps I am wrong on that. I have considered the smaller mids as a way of extending their usuable range but the displacement issue kept coming up and I am in a situation to say the least now in dealing with it.
i think yours is a very nice design. between the Vifa PL and Eton 7 i prefer the Eton. from what i remember I think the Vifa PL has better bass, the Eton better mids and your application is for a mid more than a woofer. i have not heard eton drivers for a while (10 yrs +) now so i cant say how the current ones stack up esp since the vifa PL is a more recent line.
other obvious alternates are the SS, SEAS, Focal, and Audax Aerogel. I think the Audax Aerogel works well with the 9500 also for teh bass you might want to consider Peerless 8" CSX/HDS units.
other obvious alternates are the SS, SEAS, Focal, and Audax Aerogel. I think the Audax Aerogel works well with the 9500 also for teh bass you might want to consider Peerless 8" CSX/HDS units.
Seth Smith said:
I can't make any specific recommendations as to which 5"(I'm looking myself) but with a 4th order crossover at 150-200Hz the excursion isn't going to be very much. I'd be more concerned about thermal compression at the levels you are looking at. Sadly, most of the 5" drivers seem to be designed for mid-bass use when it should be clear that there is room in the line for one which gives up some excursion in favor of efficiency for situations like this. Perhaps one of the PHL units with a passive notch to get rid of their ridiculous high frequency response. Of course most of the seemingly desireable drivers need a notch filter. At the prices they get for these things they ought to throw the notch filter in the package. Maybe Morel has something to offer.
It pays to look at the performance graphs. Whenever there is a majorly phat cone break-up (indicating ringing), there is a ripple in the impedance curve at the same frequency. That occurs at about 1.4kHz for the Focal 7K6411, and at 2.3kHz for the 6WS. As for the Eton, I've got the 7-360, and even just by looking at it I can tell it's good. The cone has 2 layers of woven kevlar (or something similar) with a honeycomb mesh in between. The total thickness of that is about 2.5mm or maybe 3mm. The dust-cap is soft so it can absorb high frequency resonances.
Re: notch filters. I had a really hard time finding any useful information on the net about them. You'll probably need a program like "Filter Wiz Pro" or something like that, which has various types of notch filters built in.
CM
Re: notch filters. I had a really hard time finding any useful information on the net about them. You'll probably need a program like "Filter Wiz Pro" or something like that, which has various types of notch filters built in.
CM
CeramicMan said:
Exactly my thinking, the rigidness is what I'm after to increase the pistonic range of this driver as much as I can. High crossover points and floppy cones don't mix. I've looked at Focal's offerings, and no units really caught my eye for this particular application. The large response spikes they exhibit at 2800Hz are just killing me, I would like the system to start as flat as possible to minimize any equalization measures later on. Perhaps I've overlooked something?
Unfortunately, that is not an option, due to the 30" physical seperation between the woofer and center of the mid/tweet section, I am forced to stay with a crossover point no higher than 400Hz and in reality, an octave lower to minimize dispersion anomalies. Thus, I have arrived and settled on the 200Hz point as an absolute limit. Again, I am active and slope is variable, in this case, the plans call for 4th order LR, again, in an effort to minimize odd dispersion patterns caused by the woofer producing higher frequency tones.
Scan Speak doesn't offer anything that convinces me of its ability to reproduce 3-4K faithfully without significant filtering aside from the Revelators which would increase my budget significantly. Seas Excels are wonderful, I've used them before, but they don't seem to like the 9 liter sealed upper chamber at all, looks like they are going to lack much warmth. Did I mention notch filtering on those yet... The Focal I've already mentioned, that resonance has got to go. Audax I am not all that familiar with in all honesty, I just looked into the Aerogel mid and it looks workable, still not as flat as I would hope for, but definately workable. Lets throw that into the mix, what can you all tell me about this speaker?
Please share your thoughts on the eaton, I know it is going to have an excursion limited problem with such a relatively high Fb, but it was necessary to achieve a smooth response. I'm going ot look into the Peerless 8" that Navin suggested later today. Do you have any additional suggestions for the bass department? Enclosure volume must stay the same or less. I figured the Eton must be better than it models as Avalon seems to extract great numbers from them. False assumption possibly?
Hello Seth
Quite an interesting design.
While I have no experience with the Eton, I have worked long enough with the Vifa PL18 to know it's strengths and weaknesses.
The PL18 is a mid-woofer designed primarily for a 2-way. In that capacity, it is actually pretty good. It goes fairly deep, has a very nice flat response which simplifies the crossover networks and cost is manageable.
But when used as a mid, as the way you intend to, it will sound slower than a true mid-range unit. It will also lack some presence when crossed at 4-5KHz. This mid-woofer sounds better when crossed at about 2.5-3KHz, with the HF unit coming in more.
You may wish to consider either a 5" or 4 1/2" true mid-range units instead. With their lighter cones, they will match the dynamics of the 8" better.
Regards
Quite an interesting design.
While I have no experience with the Eton, I have worked long enough with the Vifa PL18 to know it's strengths and weaknesses.
The PL18 is a mid-woofer designed primarily for a 2-way. In that capacity, it is actually pretty good. It goes fairly deep, has a very nice flat response which simplifies the crossover networks and cost is manageable.
But when used as a mid, as the way you intend to, it will sound slower than a true mid-range unit. It will also lack some presence when crossed at 4-5KHz. This mid-woofer sounds better when crossed at about 2.5-3KHz, with the HF unit coming in more.
You may wish to consider either a 5" or 4 1/2" true mid-range units instead. With their lighter cones, they will match the dynamics of the 8" better.
Regards
Interesting, and also sadly, what I was afraid of. I had my concerns on the PL18's energy storage as I couldn't find a waterfall on it anywhere. You seemed to have confirmed my fears in a round about way.
The Eton I would suspect will suffer from a similar problem in the upper registers, I looked at Accuton as a way around storage issues with such a high XO, but $250 for a single driver is simply out of sight for this project, that would blow most of my finishing budget in one fell swoop.
Thus we find outselves back at Seas and Visaton for a light metallic cone with a faster energy bleed that won't break the bank. I'm willing to work with an Excel as a tried and true performer, the Visaton's will take some time to really look into.
Any additional thoughts on larger diameter drivers? Just to clarify, the XO point will be between 3 and 4K, in the case of an 18cm unit, 3.5 is about as high as I am willing to go, but, I also do not want to use the cookie cutter 2K point either. In the case of a 14-15cm unit, I want to cross at 4K or higher. I am exploring the larger diameter drivers as an effort to reduce IMD through minimized excursion, although I am not certain on how the wider passband will effect that goal. My requirement of 110Db's relatively unstrained also has a hand in this decision as well.
The Eton I would suspect will suffer from a similar problem in the upper registers, I looked at Accuton as a way around storage issues with such a high XO, but $250 for a single driver is simply out of sight for this project, that would blow most of my finishing budget in one fell swoop.
Thus we find outselves back at Seas and Visaton for a light metallic cone with a faster energy bleed that won't break the bank. I'm willing to work with an Excel as a tried and true performer, the Visaton's will take some time to really look into.
Any additional thoughts on larger diameter drivers? Just to clarify, the XO point will be between 3 and 4K, in the case of an 18cm unit, 3.5 is about as high as I am willing to go, but, I also do not want to use the cookie cutter 2K point either. In the case of a 14-15cm unit, I want to cross at 4K or higher. I am exploring the larger diameter drivers as an effort to reduce IMD through minimized excursion, although I am not certain on how the wider passband will effect that goal. My requirement of 110Db's relatively unstrained also has a hand in this decision as well.
Update:
After looking into other options for the bass driver, it appears that the Scan Speak 21W-8555-01 will be a significant improvement over the Eton in the 37L box for the same money. It appears to outperform the Audax and Peerless units of similar character as well. This should be considered the bass unit as of now unless something better is lurking around out there.
After looking into other options for the bass driver, it appears that the Scan Speak 21W-8555-01 will be a significant improvement over the Eton in the 37L box for the same money. It appears to outperform the Audax and Peerless units of similar character as well. This should be considered the bass unit as of now unless something better is lurking around out there.
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