I've been working on a design for my desk that will get down to 35hz, but hopefully still have the great imaging and coherence of full range speakers.
I've done a pretty minimal 1st order crossover with just an inductor and zobel for the low pass, and a single cap with a few resistors for the high pass. The simulated response is less flat than it could be, but I'd rather keep the fewest number of components, especially capacitors, in the signal path as possible. The modeled box response for the Anarchy 7" has an f3 of 35hz in a 25L ported enclosure. I know the bass won't be detailed, but I just miss having it there at all.
I don't think I really understand the phase plots, is there something else I need to be doing for coherence? I think the voice coils will be aligned in the enclosure, but may have to tinker once the drivers arrive.
It seems like the next step is to get the drivers into the cabinets and start measuring. This is my first design after having built a few designs by others, I've done lots of reading, and some things are still over my head so please let me know if I've made any glaring errors.
I've done a pretty minimal 1st order crossover with just an inductor and zobel for the low pass, and a single cap with a few resistors for the high pass. The simulated response is less flat than it could be, but I'd rather keep the fewest number of components, especially capacitors, in the signal path as possible. The modeled box response for the Anarchy 7" has an f3 of 35hz in a 25L ported enclosure. I know the bass won't be detailed, but I just miss having it there at all.
I don't think I really understand the phase plots, is there something else I need to be doing for coherence? I think the voice coils will be aligned in the enclosure, but may have to tinker once the drivers arrive.
It seems like the next step is to get the drivers into the cabinets and start measuring. This is my first design after having built a few designs by others, I've done lots of reading, and some things are still over my head so please let me know if I've made any glaring errors.
No one seems to be responding so I'll have a go.
Inductors are usually more troublesome in a passive crossover compared to capacitors.
You don't have any baffle step compensation but if its a desk top speaker and you are listening near field then you probably don't need any.
A pic of your crossover would be useful.
Inductors are usually more troublesome in a passive crossover compared to capacitors.
You don't have any baffle step compensation but if its a desk top speaker and you are listening near field then you probably don't need any.
A pic of your crossover would be useful.
Thanks for the reply Stal. I think I posted this prematurely.
I'm going to play around with a few different enclosures built out of foam board after the drivers arrive and see how things measure in the intended spot. I'm going to do an external crossover and tailor it to my listening position since they will only be used in the one spot. There will be a good amount of room gain and they're nearfield, so I'm not too worried about baffle step, I'll probably have to pad down the woofer a bit to avoid having an uncontrolled bass canon.
I'll update once I have some measurements.
I'm going to play around with a few different enclosures built out of foam board after the drivers arrive and see how things measure in the intended spot. I'm going to do an external crossover and tailor it to my listening position since they will only be used in the one spot. There will be a good amount of room gain and they're nearfield, so I'm not too worried about baffle step, I'll probably have to pad down the woofer a bit to avoid having an uncontrolled bass canon.
I'll update once I have some measurements.
Here is the prototype speaker made from 3/4" xps foamboard in its intended spot(left) on my very messy desk:
Here are the measurements with umik-1 and REW on axis from the listening position 1/48 smoothing:
Anarchy woofer:
Fostex:
Combined in parallel:
Why am I getting the big dips at 50 and 150Hz, and why is the woofer output so much worse than the modeled response? The woofer in this cabinet was supposed to have an f3 of 35Hz but here it's 220Hz. Any help is appreciated, it seems like I didn't understand as much as I thought.
Here are the measurements with umik-1 and REW on axis from the listening position 1/48 smoothing:
Anarchy woofer:
Fostex:
Combined in parallel:
Why am I getting the big dips at 50 and 150Hz, and why is the woofer output so much worse than the modeled response? The woofer in this cabinet was supposed to have an f3 of 35Hz but here it's 220Hz. Any help is appreciated, it seems like I didn't understand as much as I thought.
Hmmm...
It's nearly impossible to measure low frequency in your room, that's why you see the bottom at 200 Hz.
The suckouts at 50 and 150 Hz are probably reflections from the environment, you better take the speaker outdoors and measure again, especially the midwoofer.
Position the mike very close to the dust cap, maybe 5 - 10cm, 2 - 4 inch in your measuring system.
I also think it's a bit ambitious to expect 35 Hz from a 7" driver regardless of enclosure type, simple law of physics.
About the xover, because you want simplicity you might be better off with a series one. It will achieve smoothness (to a degree) naturally and will let you get rid of the zobel, but keep the l-pad for the tweeter for level matching.
Also bring the two drivers as close as physically possible. That way with a low xover point they'll sound very much like a full range driver.
It's nearly impossible to measure low frequency in your room, that's why you see the bottom at 200 Hz.
The suckouts at 50 and 150 Hz are probably reflections from the environment, you better take the speaker outdoors and measure again, especially the midwoofer.
Position the mike very close to the dust cap, maybe 5 - 10cm, 2 - 4 inch in your measuring system.
I also think it's a bit ambitious to expect 35 Hz from a 7" driver regardless of enclosure type, simple law of physics.
About the xover, because you want simplicity you might be better off with a series one. It will achieve smoothness (to a degree) naturally and will let you get rid of the zobel, but keep the l-pad for the tweeter for level matching.
Also bring the two drivers as close as physically possible. That way with a low xover point they'll sound very much like a full range driver.
This is the Exodus Audio W06-017R? It would appear from a quick model in WinISD that 25 liters is waaaaaay too big for this driver. What are the diameters and lengths of your vent tubes?
jeff
jeff
Ok back to the drawing board.
The woofer is the same design as the Exodus W06-017R, but the 4 ohm version made by diysoundgroup.com
I forgot to update that I changed the internal volume for the woofer section of the cabinet to 17.5L with a tuning frequency of 37Hz using two 2"(5cm) vent tubes, each 9.25"(23.5cm) in length.
I will work on a new cabinet design with the drivers closer together vertically.
Is there software to design a series crossover? I only know PCD/WinPCD and they seem to only have parallel crossovers as an option.
My apartment/computer won't let me get the speaker outside for measurement, but I can move to an open room with the speaker away from walls and desk reflections.
Thanks Stan and Jeff.
The woofer is the same design as the Exodus W06-017R, but the 4 ohm version made by diysoundgroup.com
I forgot to update that I changed the internal volume for the woofer section of the cabinet to 17.5L with a tuning frequency of 37Hz using two 2"(5cm) vent tubes, each 9.25"(23.5cm) in length.
I will work on a new cabinet design with the drivers closer together vertically.
Is there software to design a series crossover? I only know PCD/WinPCD and they seem to only have parallel crossovers as an option.
My apartment/computer won't let me get the speaker outside for measurement, but I can move to an open room with the speaker away from walls and desk reflections.
Thanks Stan and Jeff.
Went there, but couldn't find any data for the 4 ohm version. Can you post up your TS for this driver please.
jeff
Re: 3.6
Le: 0.85mH
Impedance: 4 Ohm
Fs: 45.5Hz
Qts: 0.44
Qes: 0.48
Qms 6.37
Vas: 9.61L
Bl: 10.79
Sd: 131 cm^2
Xmax: 12mm
Le: 0.85mH
Impedance: 4 Ohm
Fs: 45.5Hz
Qts: 0.44
Qes: 0.48
Qms 6.37
Vas: 9.61L
Bl: 10.79
Sd: 131 cm^2
Xmax: 12mm
Nice.
Can you bi-amp?
I have a simple worksheet for series XOs. But you would still need to play. 1st step would be to take your existing parallel parts and wire them up as a series XO for a 1st pass.
I also have some fairly simple mods for improving both the FF85wk & the A10p (nice Mar-Ken10pT).
Below about 300 most FR issues will be room resonance (not really reflections) modes.
dave
Can you bi-amp?
I have a simple worksheet for series XOs. But you would still need to play. 1st step would be to take your existing parallel parts and wire them up as a series XO for a 1st pass.
I also have some fairly simple mods for improving both the FF85wk & the A10p (nice Mar-Ken10pT).
Below about 300 most FR issues will be room resonance (not really reflections) modes.
dave
I would prefer not to bi-amp if possible, just got a new integrated amp that I like this summer.
I would gladly use the worksheet and driver mods, are they posted somewhere?
I'm also going to give Xsim a shot.
I really like my 10pT's - great design, I plan to keep them and switch back and forth at my desk until I find a new home somewhere for them. The only remaining room with no speakers is the kitchen but it's small and poorly ventilated so I worry about cooking smoke/grease building up on them. My wife and I have been toying with the idea of moving to Victoria for a while now, the pandemic makes it a problem, but it's a 5 year goal, maybe there will be space for a listening room there.
I've been reading about bass traps today, might try some thick acoustic foam wedges in the near corner.
I would gladly use the worksheet and driver mods, are they posted somewhere?
I'm also going to give Xsim a shot.
I really like my 10pT's - great design, I plan to keep them and switch back and forth at my desk until I find a new home somewhere for them. The only remaining room with no speakers is the kitchen but it's small and poorly ventilated so I worry about cooking smoke/grease building up on them. My wife and I have been toying with the idea of moving to Victoria for a while now, the pandemic makes it a problem, but it's a 5 year goal, maybe there will be space for a listening room there.
I've been reading about bass traps today, might try some thick acoustic foam wedges in the near corner.
email me for the worksheet.
Simple cone mods are to puzzlekoat the cones of both (as little as possible, i have posted about this many times) and the rear surround/cone interface with 2-way ZIG glue (2 coats)
dave
Simple cone mods are to puzzlekoat the cones of both (as little as possible, i have posted about this many times) and the rear surround/cone interface with 2-way ZIG glue (2 coats)
dave
You are welcome.
Follow David's (Planet10) advice and you'll be on the right track.
Also have a look at this article, you'll find a few interesting points:
Series vs. Parallel Crossover Networks
Follow David's (Planet10) advice and you'll be on the right track.
Also have a look at this article, you'll find a few interesting points:
Series vs. Parallel Crossover Networks
Dave, I'm scared to do a puzzlekoat myself, but the damping on the back doesn't seem too hard. The drivers may make it out to you for enabl treatment at some point.
Stan, the article makes a good argument for a series 1st order crossover, and I bookmarked the index for all the other articles, thanks again.
Stan, the article makes a good argument for a series 1st order crossover, and I bookmarked the index for all the other articles, thanks again.
The FF85WK is a nice driver. Very well behaved I think and easy to integrate in a FAST. I have actually got it to play nicely with RS225-8 in 1st order XO similar to yours. Try putting the woofer on top and letting full range be time delayed via positioning on bottom BA stepped baffle.
Here is a XO I did for a 4ohm 8in woofer and 8ohm full range.
Here is a XO I did for a 4ohm 8in woofer and 8ohm full range.
Thanks for the tips xrk, I've read through some of your fast/waw threads and stolen ideas. I thought of using the same alignment but I was worried since these are for desktop use that having the high frequency driver closer to the desk would make reflections worse, is that not a concern?
I guess I can build a foam version and find out.
Those crossover values are very close to where I ended up in PCD. I'm going to try working out a series first order and modeling it on xsim if I can figure it out.
I guess I can build a foam version and find out.
Those crossover values are very close to where I ended up in PCD. I'm going to try working out a series first order and modeling it on xsim if I can figure it out.
It looks like the Anarchy woofer is not going to perform like I had hoped in practice with a non bi-amped passive crossover. I may switch to the Dayton RS225-4 for better sensitivity and give up the theoretical LF extension of the Anarchy.
You might check out this SB Acoustics 8in paper cone driver. Nice high sensitivity and controlled breakup at the top with a pretty flat response. I have not tried it but wanted to look at it. Only $27.
SB Acoustics SB20PFC30-4 8" Paper Cone Woofer
SB Acoustics SB20PFC30-4 8" Paper Cone Woofer
Try it again, this time with 40Hz tuning in a 14 liter box. Port is 2" dia, x 9" long. Looks decent to me.🙂
This is your tuning (see pic). It's actually more like 50Hz tuning with your port tube dims, not 37Hz.
jeff
Attachments
I just opened WinISD again and realized that I modeled the box with the T/S numbers from the 8ohm version. Thanks for catching that Jeff, it'll be nice if I don't have to buy another set of drivers.