This is a new 3 way Usher design that I just completed. It uses the Usher 9950 tweeter, 8945A 7" and 8955 8". The crossover was designed by Joe D'Appolito. The cabinet was made up from MDF ,the front baffle is 2.25" thick and is profiled on the top for reduced diffraction effects. I also made the TM portion of the baffle separate from the Woofer portion to reduce vibrational interference. Each speaker weighs about 110lbs. These speakers have turned out to be very,very nice with great detail and imaging as well as a very clean and fast low end. Bass extension is easily ino the low 30s.
FYI for WAF ,I keep these in the cabinet shown behind doors with grillcloth builtin. When I want to listen by myself critically I just bring them out into the room and position them with the correct placement.
Thanks for looking!
FYI for WAF ,I keep these in the cabinet shown behind doors with grillcloth builtin. When I want to listen by myself critically I just bring them out into the room and position them with the correct placement.
Thanks for looking!
Crossover design
I purchased the drivers from Elliot at Zalytron a while back and he sent me the design that Joe D had provided for him. It included the crossover schematics,desired box volumes and port dimensions,etc. I may play a bit with some tweaks in the future ,but it sounds great right now.
I purchased the drivers from Elliot at Zalytron a while back and he sent me the design that Joe D had provided for him. It included the crossover schematics,desired box volumes and port dimensions,etc. I may play a bit with some tweaks in the future ,but it sounds great right now.
I don't have any measurements on it. I stuck to the design from Joe D'Appolito though. I would imagine the measurements are close to the older Usher's using the same drivers with the silk dome tweeter.
Crossover
This is the crossover. I would love to hear any comments from the design experts out there.
This is the crossover. I would love to hear any comments from the design experts out there.
Re: Crossover
Hi,
Designed by J D'A or not I'm not that keen on the design.
It is one of the ways to try to get round baffle step compensation.
In this case lower bass is brought by presumably low mounting the
8" bass unit near the floor - it needs aggressive filtering to prevent
a big dip in the lower midrange due to floor reflection.
Boosting bass this way removes deep bass room gain you can use.
I cannot tell just by inspection whether baffle step higher up is
correctly handled, one would presume it is, but it would need a
fair amount of simming work or measurements to confirm it is.
I've not heard any speakers that fudge BSC that sound really neutral.
Just my considered opinion ........
🙂/sreten.
Agee said:
Hi,
Designed by J D'A or not I'm not that keen on the design.
It is one of the ways to try to get round baffle step compensation.
In this case lower bass is brought by presumably low mounting the
8" bass unit near the floor - it needs aggressive filtering to prevent
a big dip in the lower midrange due to floor reflection.
Boosting bass this way removes deep bass room gain you can use.
I cannot tell just by inspection whether baffle step higher up is
correctly handled, one would presume it is, but it would need a
fair amount of simming work or measurements to confirm it is.
I've not heard any speakers that fudge BSC that sound really neutral.
Just my considered opinion ........
🙂/sreten.
Sreten,
Thanks for your reply. I am not an expert on crossover design but I do know that fortunately I do not hear a lower midrange dip in my room. I would be interested in what frequency range you would expect the dip to cover.
I am not sure that I could handle much more bass reinforcement in my 16x19 room either. The bass extends into the low 30s ,is tight and tuneful but not overdamped.
Is your premise of the lower woofer mounting similar to the design that Audio Physic has used in the past with their side mounted 7" Scanspeak drivers mounted low?
Thanks for your input! I would like to learn more about how different speakers are designed, any comments on my latest project will help me to further my knowledge. A friend of mine has a great deal of experience with 1st order series crossovers and I considered having him take a look at this speaker with that type of crossover in mind. I don't know if these drivers would be applicable to this type of crossover or not. The FS of the tweeter is relatively low but the mid may not be smooth enough for a 1st order crossover without a lot of extra work.
Thanks for your reply. I am not an expert on crossover design but I do know that fortunately I do not hear a lower midrange dip in my room. I would be interested in what frequency range you would expect the dip to cover.
I am not sure that I could handle much more bass reinforcement in my 16x19 room either. The bass extends into the low 30s ,is tight and tuneful but not overdamped.
Is your premise of the lower woofer mounting similar to the design that Audio Physic has used in the past with their side mounted 7" Scanspeak drivers mounted low?
Thanks for your input! I would like to learn more about how different speakers are designed, any comments on my latest project will help me to further my knowledge. A friend of mine has a great deal of experience with 1st order series crossovers and I considered having him take a look at this speaker with that type of crossover in mind. I don't know if these drivers would be applicable to this type of crossover or not. The FS of the tweeter is relatively low but the mid may not be smooth enough for a 1st order crossover without a lot of extra work.
Agee said:
a) somewhat above the 220Hz (?) crossover point.
b) basically no, have seen it in Mordaunt Short Performance speakers.
c) don't try a 1st order series c/o - will not work well.
🙂/sreten.
Thanks for the info. I don't have any fancy measuring equipment but do have a Radio Shack sound level meter and test tone discs.
If anyone is interested I can take some measurements this weekend (the RS Meter doesn't measure the highs correctly from what I understand).
If anyone is interested I can take some measurements this weekend (the RS Meter doesn't measure the highs correctly from what I understand).
Sreten
You definitely know your stuff! I only have a Radio Shack DB meter but I ran a hand plotted in room measurement last night and the dip in the lower midrange was right where you said it would be. There was a trough about 8-9 db down around 250 -300hz. The frequency response from 350 on up was very flat within about +/- 2 db up to 10K. ( My meter is pretty innaccurate above 10-12K)
The lower end had a peak of 6 db at 63HZ which I suspect is a room node (I did not have time to play with placement,room treatment etc) . The -6db on the low end was about 35HZ but overall it is shelved down about 3 db.
The speakers sound detailed and image well. I suspect the detail is from the overall smooth frequency response in the high end accenuated by the lack of low midrange.
Now that I know you were correct, how would I go about correcting this? Is it simply moving the woofer up on the baffle or do I need to modify the crossover? The bass is a bit down over all,is this a case where ,with the correct cabinet volume, I would benefit from a second 8"woofer with increased bass levels and a smoother frequency response?
I have built many kits in the past but am new at the actual design end of things. Any help or suggestions would be appreciated.
Thanks!
You definitely know your stuff! I only have a Radio Shack DB meter but I ran a hand plotted in room measurement last night and the dip in the lower midrange was right where you said it would be. There was a trough about 8-9 db down around 250 -300hz. The frequency response from 350 on up was very flat within about +/- 2 db up to 10K. ( My meter is pretty innaccurate above 10-12K)
The lower end had a peak of 6 db at 63HZ which I suspect is a room node (I did not have time to play with placement,room treatment etc) . The -6db on the low end was about 35HZ but overall it is shelved down about 3 db.
The speakers sound detailed and image well. I suspect the detail is from the overall smooth frequency response in the high end accenuated by the lack of low midrange.
Now that I know you were correct, how would I go about correcting this? Is it simply moving the woofer up on the baffle or do I need to modify the crossover? The bass is a bit down over all,is this a case where ,with the correct cabinet volume, I would benefit from a second 8"woofer with increased bass levels and a smoother frequency response?
I have built many kits in the past but am new at the actual design end of things. Any help or suggestions would be appreciated.
Thanks!
Hi,
I really do not want to get into a hand waving exercise regarding redesign.
http://www.usheraudio.com/speaker-CP-8571 II.html
http://www.usheraudio.com/speaker-CP-8871 II.html
But given the specification of the two speakers and the drivers
- the latter speaker has ~ 3dB more bass end than the former.
The dip you measured depends on the axis it is taken.
The best method is to take a series of in room measurements
at a number of different positions and average all of them.
Not sine waves - warble tones or pink noise in bands.
🙂/sreten.
I really do not want to get into a hand waving exercise regarding redesign.
http://www.usheraudio.com/speaker-CP-8571 II.html
http://www.usheraudio.com/speaker-CP-8871 II.html
But given the specification of the two speakers and the drivers
- the latter speaker has ~ 3dB more bass end than the former.
The dip you measured depends on the axis it is taken.
The best method is to take a series of in room measurements
at a number of different positions and average all of them.
Not sine waves - warble tones or pink noise in bands.
🙂/sreten.
Usher 3-Way Questions
Hello Agee. I'm planning on building a 3-way system with these drivers, so I was quite pleased to stumble across the crossover design you posted. Have you modified it at all? Is the cabinet housing the 8945A ported or sealed? Likewise, for the 8955A? (I'm assuming the 8" driver is ported, but it doesn't hurt to ask.) BTW, it looks like you did a great job on the cabinets. Are you still happy with how this system sounds?
Hello Agee. I'm planning on building a 3-way system with these drivers, so I was quite pleased to stumble across the crossover design you posted. Have you modified it at all? Is the cabinet housing the 8945A ported or sealed? Likewise, for the 8955A? (I'm assuming the 8" driver is ported, but it doesn't hurt to ask.) BTW, it looks like you did a great job on the cabinets. Are you still happy with how this system sounds?
I didn't see at what frequencies the XO points are located.
Interesting to do a 3-way with 7" & 8" woofs - doesn't seem to be enough spread. Maybe the Usher 10" would be good for the lower end. I've been mulling over a 2.5 Way w/ 2 7s or 7 + 8.
Interesting to do a 3-way with 7" & 8" woofs - doesn't seem to be enough spread. Maybe the Usher 10" would be good for the lower end. I've been mulling over a 2.5 Way w/ 2 7s or 7 + 8.
I questioned the use of a 7” driver as a midrange in another thread. If you’re going to do this, why not make it a 2.5 way system? But, the crossover posted in this thread looks like it’s bandpass for the 7” driver. I guess an argument can be made for or against this approach depending on the other drivers in the system and your desired crossover points. In Usher’s CP-6381 and CP-8571II models that use the 8955A 8” woofer and a 7” driver that looks similar to the 8945A, they report relatively low crossover points of 323 Hz and 282 Hz, respectively. (The original CP-8571 crossover was even lower at 220 Hz.) My assumption is that the 8955A and 8945A will work well in this configuration. BTW, does anyone know the identity of the 7” driver used in Usher’s commercial speakers? It looks like the 8945A but has a rubbery-looking coating at the interface of the cone and rubber surround. Photos of the 8945A don’t show this coating.
any chance of posting the box design? i'm interested in building this speaker. i checked with elliot at zalytron, but he doesn't have any usher plans anymore. nice build , by the way agee.
blue934
blue934