Need some opinions
I've been planning on building a monitor for about half a year or so and have gone through many designs. I'm stuck on this one tho.
Essentially i want to know if the Vifa XT 25 (dual concentric) will go well with the Usher 8945A or 8945P(phase plug) for a 2 way bookshelf crossover at 2500 hz, probably using 2nd order, due to the low end distortion of the vifa.
Will the usher give clear strong midrange?
Does the airy characteristics of the vifa go well with the Usher? Zaph provides some very nice specs on both of the drivers if you need visuals.
Any suggestions would be helpful
Other suggestions are welcome (minus going to scan-speak for the woofer) lol too much money
What type of league would this speaker be in from the driver point of view.
thanks again
don
I've been planning on building a monitor for about half a year or so and have gone through many designs. I'm stuck on this one tho.
Essentially i want to know if the Vifa XT 25 (dual concentric) will go well with the Usher 8945A or 8945P(phase plug) for a 2 way bookshelf crossover at 2500 hz, probably using 2nd order, due to the low end distortion of the vifa.
Will the usher give clear strong midrange?
Does the airy characteristics of the vifa go well with the Usher? Zaph provides some very nice specs on both of the drivers if you need visuals.
Any suggestions would be helpful
Other suggestions are welcome (minus going to scan-speak for the woofer) lol too much money
What type of league would this speaker be in from the driver point of view.
thanks again
don
Usher 8945A woofer
I am looking at this design myself, refer to these sites for ideas:
1.http://www.partsexpress.com/projectshowcase/usher701/index.cfm
2. http://murphyblaster.com/content.php?f=usher2way.html
3.http://www.markk.claub.net/usher_index.htm
you see you don't even have to design the x-over!!
I am looking at this design myself, refer to these sites for ideas:
1.http://www.partsexpress.com/projectshowcase/usher701/index.cfm
2. http://murphyblaster.com/content.php?f=usher2way.html
3.http://www.markk.claub.net/usher_index.htm
you see you don't even have to design the x-over!!
Usher 8945
thanks for your response
can any body give me the characteristic sound of the Usher woofer. Warm, detailed etc. When compared to the peerless HDS 6.5" how does it compare??Midrange and bass.
thanks
thanks for your response
can any body give me the characteristic sound of the Usher woofer. Warm, detailed etc. When compared to the peerless HDS 6.5" how does it compare??Midrange and bass.
thanks
lewisd said:
have you thought of the usher 9930 or 9950 tweeters?
I'm curious about these and the 8945's too.
BTW I haven't build one yet, in the process of building.
I heard from those you have said that its has powerful bass, but the mid range is a little lacking.
It sure makes a good MTM speaker without A SUB WOOFER.
I heard from those you have said that its has powerful bass, but the mid range is a little lacking.
It sure makes a good MTM speaker without A SUB WOOFER.
Your going to lose
As for your question for whether the airy vifa will suit the usher, keep in mind that usher is very similar to scanspeake, and vifa and scanspeak have been successfully matched together before in retail commercial speakers. The question is do you like the sound they produce?
Keep in mind that the breakup at 6.5khz really needs to be properly removed because if it shows up then sibilance will be heard.
And lastly make sure u do something with the elevated FR above 1khz, because it will give u a forward/bright sounding vocal. Oh and u realize the impedances dont match right? Could cause problems... Just throwing it out there.
As for your question for whether the airy vifa will suit the usher, keep in mind that usher is very similar to scanspeake, and vifa and scanspeak have been successfully matched together before in retail commercial speakers. The question is do you like the sound they produce?
Keep in mind that the breakup at 6.5khz really needs to be properly removed because if it shows up then sibilance will be heard.
And lastly make sure u do something with the elevated FR above 1khz, because it will give u a forward/bright sounding vocal. Oh and u realize the impedances dont match right? Could cause problems... Just throwing it out there.
Usher 8945A
I've been designing several box sizes (data achieved from Zaph, Mark k and manufacturers spcs) using the usher and i am curious as to what the optimum box size that people have been using that resulted in good performance as the end result. I've designed pretty much everything from a bookshelf to a floor stander, but again software can only give me so much feedback, it comes back to what it will sound like in real performance.
Any feedback is welcome and appreciated
Donny
I've been designing several box sizes (data achieved from Zaph, Mark k and manufacturers spcs) using the usher and i am curious as to what the optimum box size that people have been using that resulted in good performance as the end result. I've designed pretty much everything from a bookshelf to a floor stander, but again software can only give me so much feedback, it comes back to what it will sound like in real performance.
Any feedback is welcome and appreciated
Donny
I've built a 2-way with the Usher 8945P. The cleanest midrange I've ever heard. Just what I expected from Mark K and Zaph's tests.
I've used a sealed design in my case. So I can't really help you much here. But all the existing three vented designs (Dennis Murphy's, A Feyz P's, and PE kit) with 8945P or 8945A use the PE .75 cu ft box. The A and P versions' T/S parameters are very similar.
That's why I suggested box dimensions with .75 cu ft in my 8945P design page:
http://www.geocities.com/woove99/Spkrbldg/Usher_2way/Usher_2way.htm
BTW, I've modeled a xover for the 8945P and the XT25 for someone else. But the higher frequency response between the A and P versions are different. So, you may not be able to use it. If you still want it, though, I can send it to you. Let me know.
I've used a sealed design in my case. So I can't really help you much here. But all the existing three vented designs (Dennis Murphy's, A Feyz P's, and PE kit) with 8945P or 8945A use the PE .75 cu ft box. The A and P versions' T/S parameters are very similar.
That's why I suggested box dimensions with .75 cu ft in my 8945P design page:
http://www.geocities.com/woove99/Spkrbldg/Usher_2way/Usher_2way.htm
BTW, I've modeled a xover for the 8945P and the XT25 for someone else. But the higher frequency response between the A and P versions are different. So, you may not be able to use it. If you still want it, though, I can send it to you. Let me know.
Ah thanks jay
I have looked at your design before and found it very impressive design wise, can't tell the real performance but i bet it's very good. If you wouldn't mind sending that xover it could be helpful, i can work backwards and see what you did.
I am curious to see if you have a conjugate notch like zaph's and otherwise just see what you have done with the xover.
Was this another design you considered over using the HDS? if so y?
Cheers
donny
I have looked at your design before and found it very impressive design wise, can't tell the real performance but i bet it's very good. If you wouldn't mind sending that xover it could be helpful, i can work backwards and see what you did.
I am curious to see if you have a conjugate notch like zaph's and otherwise just see what you have done with the xover.
Was this another design you considered over using the HDS? if so y?
Cheers
donny
lewisd said:
Hi Donny,
I initially used a conjugate notch. But recently I learned that an LR4 design can be done without it. A shunt resistor in parallel with the XT25 can prevent a resonance-induced peak. BTW, an LR2 slope is not appropriate for the 8945P or 8945A due to their nasty response above 2.5 kHz (combination of breakup and rolloff). In fact, very few 7" drivers can be used in an LR2 design. The Seas CA18RNX is the only driver I can think of now.
I modeled the XT25 version because someone at PE forum asked me to do so. A downside of using the XT25 with the 8945P is that the problem of 8945P's 1.2 kHz dip cannot be addressed with a 2 k or 2.5 kHz crossover point.
Luckily I found the 8945A's frd file I traced before using Zaph's IB measurement, which is also very close to the PE measurement. So, I was able to model a xover for you by modifying the 8945P xover. For diffraction modeling, I used the same baffle and driver positions that I suggested in my Usher 2-way design page for a vented cabinet. The baffle is 8.5" wide. But this xover can be used with an up to 10" wide baffle without modification. A little wider baffle will only increase the lower midrange SPL a little bit. Below is my modeling result:
An externally hosted image should be here but it was not working when we last tested it.
According to the XT25's distortion measurement, this tweeter can be used in an LR4 design with a xover frequency as low as 2 kHz. Take a look at Zaph's XT25 harmonic distortion sweep (http://www.zaphaudio.com/tweetermishmash/compare.html) and then the XT25's rolloff in the above crossover simulation. The XT25's distortions start to rise at about 1.5 kHz but its rolloff through the xover already reaches more than 10 db down at that point. So the 2 kHz xover point here is a good choice that avoids the XT25's high distortion range as well as the 7" woofer's frequency range that is prone to beaming.
The system frequency response turned out to be surprisingly good as a preliminary xover's. If you're going to use this driver combination, I'm pretty sure that this crossover will only need minor fine tuning to provide a satisfying result to you. Fine tuning options I can suggest are the tweeter level and the notch filter depth in the woofer network. The split padding resistors (R9 and R10) are on purpose. They were split to give better phase tracking as well as response shaping of the tweeter. To adjust the tweeter level, you need to vary R10, not R9. Changing R9 will only affect treble above 4 kHz. The series notch filter in parallel with the woofer is used to suppress a response hump around 700-800 Hz. Along with the primary 2.0 mH inductor, this notch filter works as a means of baffle step compensation. By adjusting the R1 value, you can conveniently control the midrange's brightness/warmness.
The designed listening axis is in the middle of tweeter and woofer axes.
Let me know if you have any questions.
Thanks Jay,
Your crossover is very impressive, it will be put to the tests soon enough if i can manage to find most of the parts in my spare pieces. I am curious as to how the real response turns out and ill post the results. thanks for your help, mainly bc my crossover didnt seem to work based on my crossover parts, only went 2nd order and didnt seem to get a good crossover slope. I just got a mic and preamp and some software, so i will be testing the stuff out as soon as i can figure everything else and set up my rig.
BTW i am leaning towards building a .75 cuft, sand filled floor standing speaker driven by some solid state amps
Cheers
don
Your crossover is very impressive, it will be put to the tests soon enough if i can manage to find most of the parts in my spare pieces. I am curious as to how the real response turns out and ill post the results. thanks for your help, mainly bc my crossover didnt seem to work based on my crossover parts, only went 2nd order and didnt seem to get a good crossover slope. I just got a mic and preamp and some software, so i will be testing the stuff out as soon as i can figure everything else and set up my rig.
BTW i am leaning towards building a .75 cuft, sand filled floor standing speaker driven by some solid state amps
Cheers
don
As you may already know, overly expensive xover parts are a waste of money. Inductors suggested in my schematic and capacitors like Dayton poly, Jantzen CrossCap, and Bennic poly will work nicely.
Tweeter Levels
Hey jay,
I have been listening to the crossover and it sounds very nice.
The only thing i would like to address would be that between 3 & 5 khz the tweeter is missing something (it sounds like its lacking detail and information in that region) its hard for me to explain. When i put an equalization of a couple of dB at 4Khz i find that its not lacking anymore. What would your suggestions be to improve the tweeter level at that point. I thought to increase the R9 value in order attenuate and to flatten above 4kHz out and the weaken the attenuation R10 and R11 values to bring it back up.
My box is 9" wide, 15" tall and 10" deep (this is just my test box that i use when testing stuff)
I plan on using your vented floor standing box dimensions for my final design.
Any ideas/suggestions as to the crossover or box would be helpful.
Donny
Hey jay,
I have been listening to the crossover and it sounds very nice.
The only thing i would like to address would be that between 3 & 5 khz the tweeter is missing something (it sounds like its lacking detail and information in that region) its hard for me to explain. When i put an equalization of a couple of dB at 4Khz i find that its not lacking anymore. What would your suggestions be to improve the tweeter level at that point. I thought to increase the R9 value in order attenuate and to flatten above 4kHz out and the weaken the attenuation R10 and R11 values to bring it back up.
My box is 9" wide, 15" tall and 10" deep (this is just my test box that i use when testing stuff)
I plan on using your vented floor standing box dimensions for my final design.
Any ideas/suggestions as to the crossover or box would be helpful.
Donny
Donny,
The dip around 4 kHz is entirely due to baffle diffraction. There is no way to fill that in with a simple xover mod, unless you want to use a couple of notch filters.
If your test baffle has sharp edges, the diffraction ripple should be worse than the simulated one, and I think that's what you hear.
The only simple way to elevate the tweeter level in frequency ranges that include 3 k to 5 kHz is to increase R11 (e.g., from the current 6 Ohms to 8 Ohms). But this may make the speakers sound bright because SPL above 5 kHz will also be increased. Changing anything else in the network will worsen the problem.
A better way to remedy the diffraction problem is to use at least 1/2" round over on baffle edges. Applying felt around the tweeter can also be tried. I'd try these methods first, and then tweak the xover later.
According to my new simulation, I need to change my statement in my original post about tweeter level adjustment. Varying R11 is a better way to adjust the overall tweeter level than varying R10 or R9. A larger value of R11 will increase the level.
The dip around 4 kHz is entirely due to baffle diffraction. There is no way to fill that in with a simple xover mod, unless you want to use a couple of notch filters.
If your test baffle has sharp edges, the diffraction ripple should be worse than the simulated one, and I think that's what you hear.
The only simple way to elevate the tweeter level in frequency ranges that include 3 k to 5 kHz is to increase R11 (e.g., from the current 6 Ohms to 8 Ohms). But this may make the speakers sound bright because SPL above 5 kHz will also be increased. Changing anything else in the network will worsen the problem.
A better way to remedy the diffraction problem is to use at least 1/2" round over on baffle edges. Applying felt around the tweeter can also be tried. I'd try these methods first, and then tweak the xover later.
According to my new simulation, I need to change my statement in my original post about tweeter level adjustment. Varying R11 is a better way to adjust the overall tweeter level than varying R10 or R9. A larger value of R11 will increase the level.
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