35.5" heightaccurate measures of the box, please
well, it might hold a bloddy big pro woofer, with a stupid fullrange, and a top tweeter
who said old style studio monitor
I dont know
off to bed
cheers
24" width
20" depth
I think the material thickness is 3/4" so looks like around 8.19cuft.
tinitus,
I believe you may have a lot of the information about what is in the simulation confused. Please look at post #162. The linked drivers are what has been used in simulation. Please explain why you believe that these drivers are poorly matched. I have reason to believe that they play very nice together.
I don't like the idea of trying to get away with 6dB/octave filters here for numerous reasons. And I have purposely used the mid-range as a "fill" driver rather than a full blown mid for many reasons as well.
The aluminum cone and 10" size of the woofer has a narly peak that has to be dealt with, a 2nd order low pass or steeper at a reasonably low frequency as shown in simulation helps take that peak out of the picture.
I would normally want to cross to the the mid-bass lower (from the lows) to get better use of that mid range unit, but this is a cost sensitive build and the x-over components necessary to do a lower x-over point would increase the price point dramatically. In fact, trying to push the X-over too much lower may require a series notch impedance correction filter on the mid-range in order to get the X-over to actually effect the mid-range unit enough, such a notch filter would have pretty high component values and costs, not to mention, a "proper" filter would almost have to be based on measurements taken after it had been box loaded.
I don't like the idea of using a ~6-7" driver above ~2.5K. They tend to get peaky and beamy and the manufacture response chart for the driver simulated supports this position.
In order to use this lower x-over point for the mid to tweeter transition, it has to be a relatively steep filter in order to protect the tweeter from mechanical damage. This design overall has a lot of dynamic range, I would hate to make the tweeter the weak link due to not giving it enough protection.
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Nines,
Please do not pay attention to the frequency range listed in the general specs for a driver. Often times the ranges listed are unacceptable if you want a reasonably "flat" performance. You need to look at the response charts, and, if possible, fine 3rd party measurements of the drivers to see if the manufacture charts are "true" or not. With the more reputable brands, the manufacture supplied charts are going to be close enough for the scope of this project in my opinion (some may disagree).
A 2 or 2.5 way is very possible and if you would like to explore that further, I suggest going back and looking at my suggestions much earlier in the thread regarding the use of the Neo8 as the high range coupled to these aluminum woofers. My previously posted sim was off because it did not properly take into account the charting error for the 10" woofers and I can't recall if I accounted for baffle loading of the Neo8. But something like that would be possible and should be considered.
Keep in mind that if you intend on building new boxes for these drivers, my x-over recommendations WOULD change. The x-over I am suggesting now, based on the drivers we have picked out, is based on installation in those wide baffle huge boxes. If you think you want to put these drivers in a more traditional upright narrow vertical alignment box, then I would suggest considering a 2.5 or 3.5 way, The mid and tweeter options if we did that would open up dramatically because we would be low passing the bottom woofer lower and dropping our sensitivity goals by ~3dB for the mid and high range drivers (or high range only, if we wanted to shoot for a 2 way). Basically, I would approach the design as possibly benefiting from a couple few dB of BSC.
Eric
I believe you may have a lot of the information about what is in the simulation confused. Please look at post #162. The linked drivers are what has been used in simulation. Please explain why you believe that these drivers are poorly matched. I have reason to believe that they play very nice together.
I don't like the idea of trying to get away with 6dB/octave filters here for numerous reasons. And I have purposely used the mid-range as a "fill" driver rather than a full blown mid for many reasons as well.
The aluminum cone and 10" size of the woofer has a narly peak that has to be dealt with, a 2nd order low pass or steeper at a reasonably low frequency as shown in simulation helps take that peak out of the picture.
I would normally want to cross to the the mid-bass lower (from the lows) to get better use of that mid range unit, but this is a cost sensitive build and the x-over components necessary to do a lower x-over point would increase the price point dramatically. In fact, trying to push the X-over too much lower may require a series notch impedance correction filter on the mid-range in order to get the X-over to actually effect the mid-range unit enough, such a notch filter would have pretty high component values and costs, not to mention, a "proper" filter would almost have to be based on measurements taken after it had been box loaded.
I don't like the idea of using a ~6-7" driver above ~2.5K. They tend to get peaky and beamy and the manufacture response chart for the driver simulated supports this position.
In order to use this lower x-over point for the mid to tweeter transition, it has to be a relatively steep filter in order to protect the tweeter from mechanical damage. This design overall has a lot of dynamic range, I would hate to make the tweeter the weak link due to not giving it enough protection.
-----------------
Nines,
Please do not pay attention to the frequency range listed in the general specs for a driver. Often times the ranges listed are unacceptable if you want a reasonably "flat" performance. You need to look at the response charts, and, if possible, fine 3rd party measurements of the drivers to see if the manufacture charts are "true" or not. With the more reputable brands, the manufacture supplied charts are going to be close enough for the scope of this project in my opinion (some may disagree).
A 2 or 2.5 way is very possible and if you would like to explore that further, I suggest going back and looking at my suggestions much earlier in the thread regarding the use of the Neo8 as the high range coupled to these aluminum woofers. My previously posted sim was off because it did not properly take into account the charting error for the 10" woofers and I can't recall if I accounted for baffle loading of the Neo8. But something like that would be possible and should be considered.
Keep in mind that if you intend on building new boxes for these drivers, my x-over recommendations WOULD change. The x-over I am suggesting now, based on the drivers we have picked out, is based on installation in those wide baffle huge boxes. If you think you want to put these drivers in a more traditional upright narrow vertical alignment box, then I would suggest considering a 2.5 or 3.5 way, The mid and tweeter options if we did that would open up dramatically because we would be low passing the bottom woofer lower and dropping our sensitivity goals by ~3dB for the mid and high range drivers (or high range only, if we wanted to shoot for a 2 way). Basically, I would approach the design as possibly benefiting from a couple few dB of BSC.
Eric
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the Dayton mid is a better match than the Celestion
might also have been my choice
but I dont know any of those drivers
I noticed a 15" Peavey
but whatever, its impossible to say exactly how it will work anyway
not going to make it a contest or battle
and I have no idea what is expected of the result
good luck, cheers
but theres no way to guarantee it will actually happen
neither do I
but its 'easier' to change, thats all
probably, yes
have you considered to try a sim on the 15" Peavey I mentioned ?
(I still wonder how you could say the Celestion would be a 15ohm driver, but thats obviously 'history' now, with other Dayton mid)
My dad likes this so far what are the crossover points? Did you end up making the diagram better?Not bad IMO....
The sim includes resistance of the inductors as listed in the cart. If the OP is willing, I would suggest upgrading "low L1" to the 15GA option from Jantzen. The rest I would just use the 20GA units.
Drivers:
Vifa BC25SG15-04 1" Shielded Dome Tweeter 264-1026
Dayton PK165-8 6" Professional Kevlar/Paper Cone Midrange 295-020
Dayton Audio DA270-8 10" Aluminum Cone Woofer 295-334
That's $180 worth of drivers and $120 worth of X-over
I believe the OP wants to stick with 2x10" drivers because the cabinets already have cutouts for 10" drivers. If that is not a limitation then hopefully the OP lets us know. A single larger driver would not be a bad idea, though to be honest, the dayton 10" drivers do model out just fine in that box size. Assuming ~8ft^3, sealed would work fine, vented and tuned anywhere from 18-28hz could work fine (depending on taste). It happens to match up well with the drivers IMO. Though that size also would be great for a lot of 15-18" woofers out there as well. If it were my personal project re-using those boxes, I think I would be tempted to use the 8ft^3 boxes as a place to put some 18" woofers into, then build some smaller boxes (or use those ones laying there in the picture) to build some "2-way" jobs that would sit on top of those big cabinets. If the 15-18" were something with good behavior up to ~500hz, then I would be comfortable with a passive x-over similar to the one proposed for the current build.
The chart below is the one I found for the celestion sealed back mid-range. Perhaps I am not reading it right, but the lowest resistance point on the plot appears to be ~15ohM @20hz. Are you seeing something different here? The chart suggests ~16oHm driver, but the specs claim 8oHm. the chart claims "1W" was used for the plot, but was that 2.83V (assuming an 8 ohm) or 4V (assuming a 16ohm?). Without knowing the voltage used to make the chart, any simulation could have the driver off by 3dB.
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pitty
but I think he actually corrected that, and said it was ok to change front baffle
looks perfectly 'normal' to me
but from looking at thousands of them, its obvious they are not always logical
hey, Im not questioning your sim skills, not at all
I have zero sim ability, but have to rely on knowing the drivers I use
but it tells that if you had used the Celestion, something would have gone awfully wrong
well, that one is history
ofcourse anyone can make a mistake
but this would have been really bad
The exact x-over points are not terribly important. Very roughly speaking, they are somewhere around 750hz and 2500hz. Which is what modeled out well while keeping component costs relatively low (only about $7 more per x-over that the pre-built units and no iron core here, all air!), but the component values have been adjusted (some higher some lower) than what a paper/java-calculated x-over would spit out in order to contour the driver roll-offs to mate up better.
Keep in mind, of course, that the x-over assumes that the manufacture supplied charts are reasonably accurate. Also, keep in mind, that I am human and may have screwed up somewhere, so it would not be a bad idea for someone to confirm the simulation by carrying it out themselves from the start.
Here's a better looking wiring diagram.... I just spread out the low and highs so there aren't connections crossing through the band-pass part of the filter that make it hard to read. Also, put some logical "spacing" in there to make it easier to mentally isolate the different filter sections.
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Nines,
Hold off on ordering anything...
I screwed up
For some reason I got confused about the situation with the 8 ohm mid range, thinking that since it would be running at half the power from the 4 ohm high and low frequency sections, that I needed to subtract 3dB from the drivers response in order to properly integrate it, however, I *think* that was incorrect because all of the drivers in the simulation were charted at 2.83V originally, so the impedance difference did not need to be adjusted for.
I believe the following is what it would actually look like.... (there are a couple changes to the x-over in the following) With this in mind, I believe we could use a mid range unit with less sensitivity and be alright.
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Ok... same drivers... made some adjustments to compensate for the previous mistake and believe that my original instinct on the high sensitivity needs on the mid range was correct after-all. However I suspect that we could use a lower sensitivity driver if we wanted to.
The new component values actually move the lower x-over a little lower which is a good thing IMO. It's somewhere around 500-600hz now. Switched "Low C1" to electrolytic to help reduce component costs.
The new component values actually move the lower x-over a little lower which is a good thing IMO. It's somewhere around 500-600hz now. Switched "Low C1" to electrolytic to help reduce component costs.
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ok thanks it all looks amazing and we plan on ordering everything tomorrow I believe. But you are right it would be nice to have someone take a look at it for a 2nd pair of eyes before we buy it all.
you are aware that two paralel woofers is pushing many amps to their absolute limits ?
ofcourse not all, but many wont like it at all
I just hope you have good stable amps
btw, did you calculate the BSC ?
hell, I remember even mr Geddes asking, what is BSC
at least we could teach him that
(just asking)
ofcourse not all, but many wont like it at all
I just hope you have good stable amps
btw, did you calculate the BSC ?
hell, I remember even mr Geddes asking, what is BSC
at least we could teach him that
(just asking)
The amp is an Adcom GFA-545 II and we are willing to change the baffle to a different size woofer but I can't find any 12" that have a vas near 8 cuft which would be needed since the boxes are 8cuft. My dad doesn't want to use a 15.
He has an adcom amp that is rated to run 4 ohm loads. I see no reason the amplifier would not be able to do so gracefully, especially if the specifications are true (no reason to doubt them at this point)....
http://www.adcom-usa.com/userguides/gfa-545II-ug.pdf
24" wide baffles, cabinets placed right against a wall, and a 15" active sub. I can't think of any reason to worry about baffle lossesbtw, did you calculate the BSC ?
hell, I remember even mr Geddes asking, what is BSC
at least we could teach him that
(just asking)
-------
I'm hoping one of the resident experts could chime in on the zobel for the mid-range. I was just tinkering and preferred the results with a 4 ohm resistor rather than an 8 ohm (it's an 8 ohm driver). I'm just wondering if there is anything "wrong" with doing this. I realize that it effects the way the x-over behaves in the higher frequencies, but this seems to be a "good" thing in this particular situation.
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budget is a problem with that
I didnt find any good looking 12" either
or at least not one I would dare suggest
thats why I suggested the 15" Peavey
looked perfect fore this big box
but whatever, if your dad pays, what can go wrong
btw, VAS is not equal to box volume, as such
depends on other specs how the optimal box turns out
closed box is a lot more' forgiving' than BR
but low end rolloff can still vary with different box size
no box calculation/simulation yet
bloddy hell, with additional double tens, sounds like dad is planning a small disco
He can tune that big box to anywhere from 18-28hz and it's going to sound fine IMO. The simulation that I did has a box sim spliced in from 200hz down. I think it was based on a hypothetical box we discussed earlier in the thread. Think it may have been a 5ft^3 box tuned fairly low. Changing the box really has no impact on the x-over so i didn't worry about splicing in the "exact" box, just something close.
I'm thinking that a proper port and the little box that needs to be constructed for the mid range driver could actually share common baffles in order to save on wood.
What peavey driver was that you had in mind? I skimmed the thread and can't find anything.
Eric
I'm thinking that a proper port and the little box that needs to be constructed for the mid range driver could actually share common baffles in order to save on wood.
What peavey driver was that you had in mind? I skimmed the thread and can't find anything.
Eric
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I remember even mr Geddes asking, what is BSC
at least we could teach him that
LOL.
Seriously though, I'm sure the hobbyist methodology is just as amusing in reverse
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