Hi!
Im using some components Ive got to reload a burnt out Powerworks RS 82 PA top cabinette.
What crossover frequency should be used, and - if possible - could I get some help with getting the values and schematic of the needed components?
Running a mac at the moment and there aren't a whole lot of crossover software, should Ive known how to use them... I saw the great guide here though, and will read into that.
The woofer is the EV 8L found here: https://www.thomann.de/se/ev_8_speaker_type_560459100.htm
Tweeter is the PHT-407 found here: http://paudio.co.uk/products/P-Audio_PHT-407_15W_Compression_Driver_With_Horn.php
Woofer: 8ohm, 91.2 db
Tweeter: 8ohm, 98 db
While the specifications are to be found on the links above, I will of course post whatever values needed - I just don't know where to start.
The box is what it is. While I'm hoping for at least some low end, it is originally designed to be used with a subwoofer. Maybe we shouldn't expect miracles though - so lets focus on a smooth midrange 🙂
Best regards, Björn
Im using some components Ive got to reload a burnt out Powerworks RS 82 PA top cabinette.
What crossover frequency should be used, and - if possible - could I get some help with getting the values and schematic of the needed components?
Running a mac at the moment and there aren't a whole lot of crossover software, should Ive known how to use them... I saw the great guide here though, and will read into that.
The woofer is the EV 8L found here: https://www.thomann.de/se/ev_8_speaker_type_560459100.htm
Tweeter is the PHT-407 found here: http://paudio.co.uk/products/P-Audio_PHT-407_15W_Compression_Driver_With_Horn.php
Woofer: 8ohm, 91.2 db
Tweeter: 8ohm, 98 db
While the specifications are to be found on the links above, I will of course post whatever values needed - I just don't know where to start.
The box is what it is. While I'm hoping for at least some low end, it is originally designed to be used with a subwoofer. Maybe we shouldn't expect miracles though - so lets focus on a smooth midrange 🙂
Best regards, Björn
Well... with the above in mind your first step will be to find a differnet tweeter to use. That driver is a supertweeter designed to add sparkle at the very top of the spectrum above a midrange or large format CD. Crossed lower 2-3khz it will sound bad and I'm not sure that 8" will sound good crossed that high. I have a set of 8" boxes that do use a similar supertweeter but it's paired with an 8" fullrange driver and is crossed at 5khz, this sounds very smooth but the boxes don't produce much lowend so a sub is necessary.
Oh, please, your hurting me 🙂
(just kidding ofcourse)
I actually got two of those, and a pair of hp10w from a "come to an end boominator project", and thought if they can be used in the boominator, they should work here as well...
I mean, this EV 8L driver seem to break up at a higher frequency than the hp10w. And if the tweeter work in that configuration, it should have an easier job in my case. Or am I wrong?
Should remember the benchmark here; the original woofer (https://h-audio.de/Lautsprecher-PA/...-426-WG-4-z004690-8-Subwoofer-160W::2927.html) breaks up around 2 khz (graph is quite ugly) and it matches up against a piezo tweeter.
Ofcourse, if this is a bad idea, then I'll try to find something else.
Tanks for the input @conanski, cheers! 🙂
I tried a 2khz crossover in my build just like you are suggesting and it sounded ugly even at low SPL. a cone driver can be extended to a higher than ideal crossover frequency without much sonic penalty but a tweeter can't handle a lower crossover at all, and that shouldn't be a surprise because they don't have much excursion capability. It's been my experience that high frequency drivers in general sound better with crossovers that are higher than the manufacturers absolute minimum rating, by all means try it out but I suspect you will find it needs to be quite a bit higher than 2khz to sound good.
Thanks for your input @conanski, much appreciated!
Since the driver is in my possesion allready, I think I might try..
However, for this driver, where would you draw the line (how low would you go)?
Let's say the EV driver would be allright up to 3,5 khz, would that be acceptable?
Think I will bring home a dsp and try it out a little...
---
On the other hand, what reasonably priced driver, avalible in europe, would you propose?
I do have another 1" horn, but it is too large. I could reuse just the driver though.
Since the driver is in my possesion allready, I think I might try..
However, for this driver, where would you draw the line (how low would you go)?
Let's say the EV driver would be allright up to 3,5 khz, would that be acceptable?
Think I will bring home a dsp and try it out a little...
---
On the other hand, what reasonably priced driver, avalible in europe, would you propose?
I do have another 1" horn, but it is too large. I could reuse just the driver though.
Well, gave it a try. Got both some failure, and also kind of sucess 🙂
So, crossing it over at 3500hz sound awful. Got an extreme peak around that point ofcourse.
Solution was to roll off the woofer from 2250hz 6db, and let the tweeter meet up as high as 7000hz 12db. Also had to lower the tweeter a bit. To my ears it sound nice crossed this way. The higher end is clear and smooth, but still too agressive. I'm actually happy this way as of now, but will listen in a few more hours. Will also test to crank it a bit to see if it holds up.
Will see if I can do a simple measurement of the response some day to see if my ears are lying... and perhaps make some adjustments.
This setup was made using a simple dsp on a Behringer iNuke. However, how do I translate this to values of the components needed to make a crossover?
So, crossing it over at 3500hz sound awful. Got an extreme peak around that point ofcourse.
Solution was to roll off the woofer from 2250hz 6db, and let the tweeter meet up as high as 7000hz 12db. Also had to lower the tweeter a bit. To my ears it sound nice crossed this way. The higher end is clear and smooth, but still too agressive. I'm actually happy this way as of now, but will listen in a few more hours. Will also test to crank it a bit to see if it holds up.
Will see if I can do a simple measurement of the response some day to see if my ears are lying... and perhaps make some adjustments.
This setup was made using a simple dsp on a Behringer iNuke. However, how do I translate this to values of the components needed to make a crossover?
Yes... that is very much what I suspected. There is a 6dB difference in sensitivity between drivers on paper so the tweeters need to be turned down at least that much relative to the woofers, but maybe even a little more once the woofer response is flattened. Measuring the speakers should confirm much of what your ears are telling you but may also highlight areas that need work, Our ears are most sensitive in the 2-5khz range so distortion or even just a rise in response here will be very obvious and intolerable. Flattening a woofers response is done with baffle step EQ in a passive crossover, it is possible to implement notch filters too and level adjustments between drivers is accomplished with an L-pad resistor network. All this can be achieved with DSP too but most people want the speakers to at least be usable without it so some combination of passive and active processing has to be arrived at. Your call there. Have a look online for a passive crossover calculator, that will give you component values to build what you want. There is a level of interaction between crossover components and the real world response of the drivers that isn't accounted for with textbook filter calculators though so the basic passive version won't exactly match the active, to close that gap a program that takes the drivers response into account will produce better results, these programs are usually something you download and you have to add driver response files to generate a crossover design.
Thanks again.
This started off as a ”I’m bored during covid quaranteen”-project, and I thought it would be done quite swiftley. It seem to be the oposite 😅
However I don’t mind. I found a video on how to construct a small cable that will be able to measure T/S prameters throuhh REW. Think I will take some time looking into that both for the purpose of this project, but also for the future.
After getting some proper parameters, I will look into constructing a filter. I have a software, Basta, which should be good enough onve Ive got the T/S values.
I’ll keep you posted. 😊
This started off as a ”I’m bored during covid quaranteen”-project, and I thought it would be done quite swiftley. It seem to be the oposite 😅
However I don’t mind. I found a video on how to construct a small cable that will be able to measure T/S prameters throuhh REW. Think I will take some time looking into that both for the purpose of this project, but also for the future.
After getting some proper parameters, I will look into constructing a filter. I have a software, Basta, which should be good enough onve Ive got the T/S values.
I’ll keep you posted. 😊
EV crosses them at 1.7khz in their ZX1 system. Google that system for details of what tweeter etc they use.
Yes REW works well, I have a Dayton EMM6 mic that I connect via a Mackie ProfX8 which has built-in USB and phantom power.
Hi!
They use a custom molded horn together with their own drivers. Problem is, I allready got the PHT-407 at hand, and will try to use them.
During my first tryouts with the active filter, I like what I hear - this is doable. However, hard part will be to figure out the crossover.
Thanks for the advice, have a great day! 😊
Hi,
You're best to model in something like VituixCAD rather than just use generic calculators, as that way you can take account of all of the frequency response and impedance curve, not just a nominal value.
Unfortunately for this to work, we'd need a frequency response and impedance curve for the woofer as well, preferably in the enclosure. Are you able to measure those too?
For crossover purposes, you'd be able to get away with measuring from a couple of hundred Hz on up, which simplifies measuring indoors as you've less concern about reflections forcing you into too much gating.
Here's a quick attempt at getting the HF part to match a textbook 7kHz Butterworth 12dB HPF, which is what I'm assuming you used in your earlier digital tryout.
I've tried to match it to the nominal 91dB sensitivity you mentioned for the EV8L, but that doesn't account for bafflestep, so may need padded down further.
You're best to model in something like VituixCAD rather than just use generic calculators, as that way you can take account of all of the frequency response and impedance curve, not just a nominal value.
Unfortunately for this to work, we'd need a frequency response and impedance curve for the woofer as well, preferably in the enclosure. Are you able to measure those too?
For crossover purposes, you'd be able to get away with measuring from a couple of hundred Hz on up, which simplifies measuring indoors as you've less concern about reflections forcing you into too much gating.
Here's a quick attempt at getting the HF part to match a textbook 7kHz Butterworth 12dB HPF, which is what I'm assuming you used in your earlier digital tryout.
I've tried to match it to the nominal 91dB sensitivity you mentioned for the EV8L, but that doesn't account for bafflestep, so may need padded down further.
Hi!
Sorry for my late reply. Work... However, I should be able to measure the impedance and frequency. Just got my hands on a used EMM6 measuring mic. First and foremost I will do some educating (e.g. watching YouTube) on how to measure with REW. When I'm confident I get somewhat decent results, I will get back and see how the measure need to be done.
I could in theory do the measure outside, but its -10 C here at the moment, and it will probably stay around that for a while. From what I believe most calculations and such are normally done around indoor temperature, 20 C, so it might be off...
Indoor measure it is then.
As said, I will get back, thank you so much for both your advice and the calculations so far!
Best regards,
Björn
No worries about the timing, take as long as you need.
Not sure how much you know about measuring, but one of the factors that complicates full range measurements indoors is that it's really hard to separate out room reflections as the wavelength is so long.
In your case though, we only need enough of the midrange included in the measurements to get a sensible idea of the average level there, so you can afford to gate your measurements which should help avoid that problem, so no need for sub zero expeditions 👍.
Not sure how much you know about measuring, but one of the factors that complicates full range measurements indoors is that it's really hard to separate out room reflections as the wavelength is so long.
In your case though, we only need enough of the midrange included in the measurements to get a sensible idea of the average level there, so you can afford to gate your measurements which should help avoid that problem, so no need for sub zero expeditions 👍.
Hi!
Yeah, I know about all the problems reflections can cause, both dips and peaks. I do understand what your'e after. Measuring only a small part of the spectra should give the oportunity to exclude reflections both in time and frequency I guess.
At least I have calibrated my microphone and soundcard (using a Yamaha AG06, a small mixer), and will now attemt to do some measuring. Found som "articles" and yes, videos, on the subject so I will try to see if I can make it work.
I'll be back 😎
Yeah, I know about all the problems reflections can cause, both dips and peaks. I do understand what your'e after. Measuring only a small part of the spectra should give the oportunity to exclude reflections both in time and frequency I guess.
At least I have calibrated my microphone and soundcard (using a Yamaha AG06, a small mixer), and will now attemt to do some measuring. Found som "articles" and yes, videos, on the subject so I will try to see if I can make it work.
I'll be back 😎