That midrange is far better than the woofer. I use the Audax in my 3-way.
I have a big issue with the woofer. It really isn't going to play well in the bass region for HiFi. Actually, it totally unsuitable. The Fs is 47 Hz and if you look at the plots below, all it will take is about 100 Watts at 40 Hz to exceed the Xmax of the driver.
I created a 4 cubic foot box with two 4" vents to get maximum bass. F3 is 70 Hz, which is going to be useless with out a sub.
The other alternative is a sealed cabinet. For a Q of .7 you need a 1.1 cubic foot cabinet. The F3 is now 125 Hz, which is worse. The good news is that Xmax at 100 Watts is okay through the whole audible range, barely.
An externally hosted image should be here but it was not working when we last tested it.
For the vented box, the amount of power required to "blow" that driver gets substantially less when you go further down in frequency. 50 Watts will exceed Xmax at 30 Hz and it gets worse as it goes deeper. You need a very steep filter to protect the woofer from over excursion.
None of the above takes into account that the kevlar cones on woofers tend to have some nasty cone breakup at the upper end that could make some irritating noises in the lower mid frequencies.
The long and short of it is that using that woofer is bad advice. While the Audax is a very good mid, the cost of the mid and the Fostex will set you back $220 plus shipping. Then you will need replacement woofers with high SPL, which is not going to be cheap or additional filtering to protect the Peaveys from destruction.
The cheapest solution is to sell the Peavey woofers and buy the Dayton DC380-8 woofers, keep the mid and tweeters you have and build a nice box. This will save you from buying one or more subs if they are mounted in a large cabinet (see my earlier post), which a sub is going to be costly when you think about buying a suitable woofer, cabinet, filters, and sub amp.
Let's go back to square one.
1. What is the budget to complete this speaker design?
2. What are your goals for this system?
a. What amp will you drive this with?
b. What will the system be used for (Home Theater, HiFi)?
c. Any other special requirements?
Please give us the answers to those questions and it will be easier to nail down a design that fits the budget and serves your listening needs.
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Here is the sealed cabinet design for the Peavey. The yellow traces are for the sealed cabinet. The red is the vented design.
An externally hosted image should be here but it was not working when we last tested it.
Hi Loren42 thanks for your advice and the time you took to do those plots.
Yes, theres is always the possibility of selling the Peaveys but if there even a slight chance of keeping them and doing something decent, I will have to take it. The story is that some time ago my girlfriend and me were going around checking some speakers and sound systems and I happened to say out loud that I loved those Black Widows since they reminded me of some Peaveys I used to have 10 years ago. Next thing I know she showed up with them in my birthday 2 months later. So as you can see, it will be REALLY difficult to get rid of them.
So, the next step would be to see how to make them work. (if possible).
Answering the questions:
Budget is uncertain but I dont think I can spend more than $200 more after buying the Audax Midranges and the Fostex tweeters. at least for now.
The goals for the system are just a home theater sound system that can deliver a big low end punch when needed in a movie ( I dont know the technical or slang word exactly, I dont mean very low gut moving frequencies like 20Hz or so but more in the range of what you will hear in Pink Floyd's the wall, that bass that kicks you back). Also can be used once in a while for a party with mostly rock and trans music for example.
Amp wise for the moment I dont have anything powerful, just an old Technics SA-GX530 receiver but we are saving to buy something much better as soon as we can.
There are no other requirements.
I have an Audiosource PSW100 subwoofer for now also that picks up the low frequencies in the movies pretty well and I dont think I need much more for the moment.
So with that subwoofer maybe the Peaveys can be placed in a sealed box to prevent them from reaching the Xmax?
Thanks again for your help...
Leo
Yes, theres is always the possibility of selling the Peaveys but if there even a slight chance of keeping them and doing something decent, I will have to take it. The story is that some time ago my girlfriend and me were going around checking some speakers and sound systems and I happened to say out loud that I loved those Black Widows since they reminded me of some Peaveys I used to have 10 years ago. Next thing I know she showed up with them in my birthday 2 months later. So as you can see, it will be REALLY difficult to get rid of them.
So, the next step would be to see how to make them work. (if possible).
Answering the questions:
Budget is uncertain but I dont think I can spend more than $200 more after buying the Audax Midranges and the Fostex tweeters. at least for now.
The goals for the system are just a home theater sound system that can deliver a big low end punch when needed in a movie ( I dont know the technical or slang word exactly, I dont mean very low gut moving frequencies like 20Hz or so but more in the range of what you will hear in Pink Floyd's the wall, that bass that kicks you back). Also can be used once in a while for a party with mostly rock and trans music for example.
Amp wise for the moment I dont have anything powerful, just an old Technics SA-GX530 receiver but we are saving to buy something much better as soon as we can.
There are no other requirements.
I have an Audiosource PSW100 subwoofer for now also that picks up the low frequencies in the movies pretty well and I dont think I need much more for the moment.
So with that subwoofer maybe the Peaveys can be placed in a sealed box to prevent them from reaching the Xmax?
Thanks again for your help...
Leo
Ah, a gift. Yes, let's make it work for you.
Leo, go with the sealed box.
Does your amp have a home theater mode with a "small" mode? That will cut off the low end so that you can integrate a sub without an external filter.
The sub is the only way you will get any bass. An F3 of 125 Hz is essentially, no bass at all. So, a sub is the only recourse.
The sealed cabinets can be small with a maximum internal volume of 1.1 cubic feet (.823 is ideal). If you make the box larger, the Q of the box goes down and the F3 point will raise. This means the bass will get weaker and your Xmax problem will return.
The ideal Q is usually .7. Than would yield a box volume of .823 cubic feet.
As the box continues to get smaller your Q raises and the bottom end develops a hump that will boom at those notes. .3 cubic feet has a Q of 1. I doubt that you can make the cabinet that small.
Unfortunately, the Peavey was really intended for a vented enclosure, so the sealed volumes are really small. .823 is the flattest response curve and still keeps Xmax below the limit at 100 Watts.
So, .823 is the perfect theoretical volume and 1.1 cubic feet is the absolute largest for safety at 100 Watts.
If you drive more power above 100 Watts you risk Xmax excisions above the limit.
I should add that there is something called Xmech, which is the physical limit where the voice coil either slams into something or extends to the point of damage. Peavey did not publish that number, but you can safely assume that Xmax is not going to damage the driver. You just don't know how much further it will go before Xmech is reached and how resilient the driver is to that limit.
I'll look into modeling a crossover with the Audax and tweeter you want to see if I can get a crossover design for you that is simple.
Okay. Scrap the 3-way design altogether and ditch the Audax.
The Peavey and Audax have almost identical frequency responses, so it will not work. The Peavey is really a mid-bass and not a real woofer anyway.
The only choice is a 2-way system. Ideally, a horn would be required and use about a 1 kHz crossover, but that gets complex and probably expensive to do right. However, the Peavey might be coached to stretch to 2 kHz and a ribbon tweeter used.
This is modeled with a Fountek NeoCd3.0M ribbon. It is not bad, but could be better. I could not find enough Thiele-Small data for the Fostex tweeter, but the Fs is not low enough anyway. The minimum crossover frequency is 5 khz, which is way, way too high. Scrap that tweeter.
So, here is your 2-way design. Not perfect, but you might give it consideration:
This is a 2-way design that should work. The Fountek is $82, but since you don't need a midrange, you actually save money!
The crossover is a bit cheaper, too. So, I added a EQ circuit, which will be a little more expensive. The inductor Lm is a big one, but since it is not part of the signal path you can use an iron-core to save size and cost.
You need the following components for the EQ network:
Req = 6.8Ω
Ce = 6.8 µF
Rm = 0.47Ω
Lm = 8 mH
Cm = 1.5 mF
These keep the impedance flat throughout the band.
There is a dropout at 6 kHz that I do not like. I think that there may be a better choice for a tweeter, but I don't know what it is. You can always EQ this if you have to, but I think this design is a good concept for where you need to go. Also, when you look at Fountek's published frequency graphs that did is not there, so in reality it may not be a problem.
The stated SPL of the Fountek is only 95 dB/Watt/meter. That is a little low, too, but you really don't have a lot of good choices here. Maybe someone has some thoughts?
The Peavey and Audax have almost identical frequency responses, so it will not work. The Peavey is really a mid-bass and not a real woofer anyway.
The only choice is a 2-way system. Ideally, a horn would be required and use about a 1 kHz crossover, but that gets complex and probably expensive to do right. However, the Peavey might be coached to stretch to 2 kHz and a ribbon tweeter used.
This is modeled with a Fountek NeoCd3.0M ribbon. It is not bad, but could be better. I could not find enough Thiele-Small data for the Fostex tweeter, but the Fs is not low enough anyway. The minimum crossover frequency is 5 khz, which is way, way too high. Scrap that tweeter.
So, here is your 2-way design. Not perfect, but you might give it consideration:
An externally hosted image should be here but it was not working when we last tested it.
This is a 2-way design that should work. The Fountek is $82, but since you don't need a midrange, you actually save money!
The crossover is a bit cheaper, too. So, I added a EQ circuit, which will be a little more expensive. The inductor Lm is a big one, but since it is not part of the signal path you can use an iron-core to save size and cost.
You need the following components for the EQ network:
Req = 6.8Ω
Ce = 6.8 µF
Rm = 0.47Ω
Lm = 8 mH
Cm = 1.5 mF
These keep the impedance flat throughout the band.
There is a dropout at 6 kHz that I do not like. I think that there may be a better choice for a tweeter, but I don't know what it is. You can always EQ this if you have to, but I think this design is a good concept for where you need to go. Also, when you look at Fountek's published frequency graphs that did is not there, so in reality it may not be a problem.
The stated SPL of the Fountek is only 95 dB/Watt/meter. That is a little low, too, but you really don't have a lot of good choices here. Maybe someone has some thoughts?
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Thanks Loren. I am still digesting all the information. So that means that the box if closed box is used will have to be pretty much the size of the speaker, barely big enough to surround it? That sounds so strange
I see why this speaker was made for vented enclosures. Gives me something to think.
Something strange though (even though it doesn't change anything dramatically but does change a little) Is Fo and Fs basically the same? I couldnt find any comparison? because the Fo on the Peavey website shows a 47.8 Hz. But on the papers that came with the speakers and another page on their website shows an Fs of 42.4 Hz.
Thanks for helping and looking into the crossover.
Leo
I see why this speaker was made for vented enclosures. Gives me something to think.
Something strange though (even though it doesn't change anything dramatically but does change a little) Is Fo and Fs basically the same? I couldnt find any comparison? because the Fo on the Peavey website shows a 47.8 Hz. But on the papers that came with the speakers and another page on their website shows an Fs of 42.4 Hz.
Thanks for helping and looking into the crossover.
Leo
Yes, I have been embellishing on the last post, so you might reread it.
God knows what the real T/S parameters are on that woofer. You really need to measure it with something like a Woofer Tester 2 to be sure.
Ok Loren, I have some more questions now to help me understand everything. I know that the tweeter receives or uses much less power than the mid or woofer specially. In a case of a 2 way like the one you are proposing, the tweeter ( Fountek NeoCD3.0) has a 17W and 40W max power handling, will it be enough? Because it is much less than the comparable dome ones. (without the dB to match unfortunately)
Another question is about the crossover point with the 2 way, it will be in the 1.5 to 2KHz region and while I was researching I found so many threads explaining why you have to try to avoid placing any crossovers in the 400 to 4000 Hz region of the vocals. Will it be something that you think will be noticeable?
The last thing is regarding what you said in the first post of this page: "I created a 4 cubic foot box with two 4" vents to get maximum bass. F3 is 70 Hz, which is going to be useless with out a sub" that was with a vented design that you scrapped because you didnt know I had a sub. Including the sub in the equation to take care of anything under 90 Hz or so should take care of that problem?
Thanks...
Leo
Another question is about the crossover point with the 2 way, it will be in the 1.5 to 2KHz region and while I was researching I found so many threads explaining why you have to try to avoid placing any crossovers in the 400 to 4000 Hz region of the vocals. Will it be something that you think will be noticeable?
The last thing is regarding what you said in the first post of this page: "I created a 4 cubic foot box with two 4" vents to get maximum bass. F3 is 70 Hz, which is going to be useless with out a sub" that was with a vented design that you scrapped because you didnt know I had a sub. Including the sub in the equation to take care of anything under 90 Hz or so should take care of that problem?
Thanks...
Leo
And another question, I know that the lower the impedance the more power that flows to the driver so it should be kept all at the same or maybe do 2 in parallel to lower it or series to raise it if need be.
But for example the Fountek NeoCD3.0 is a 7 Ohm tweeter, will it do much problem since its going to get a little more power than anticipated?
What about one like the Aurum Cantus G2Si from partsexpress that is 6 Ohms?
Because that one has 96 dB even though the rest of the specs like Fs are not there
Leo
But for example the Fountek NeoCD3.0 is a 7 Ohm tweeter, will it do much problem since its going to get a little more power than anticipated?
What about one like the Aurum Cantus G2Si from partsexpress that is 6 Ohms?
Because that one has 96 dB even though the rest of the specs like Fs are not there
Leo
Okay, the biggest unknown is the actual frequency response of the Peavey woofer. I feel comfortable about the lower end, but no clue as to how high the driver goes before it peters out and what the off-axis response is going to be.
Again, the only way to really be sure is to measure it and I know that is something you will not be able to do.
So, the question is, what to mate it to? The lower the crossover point the better. However, it is very hard to get a tweeter that goes very low.
Here is another try using Aurum Cantus G2Si ribbon. I like the response here better than the Fountek and it is more efficient at 96 dB, which better matches the woofer. These are about $90 each at Parts Express.
An externally hosted image should be here but it was not working when we last tested it.
Your questions:
About 50% of your power goes to the woofer below 500 Hz. So, a tweeter with a 40 Watt rating is probably okay when crossed at 2 kHz.
There are rules of thumb for optimum crossover points. They are not that important for your design because you are more limited with your choice of drivers and you have to live with what you get. Crossing at 2 kHz and up is way better than 1 kHz and there are some stunning loudspeakers built that have a 1 kHz crossover. So, don't fret it.
Don't use the vented design because you have a sub and the vented design will be tricky with Xmax. Stick with a sealed design.
And another question, I know that the lower the impedance the more power that flows to the driver so it should be kept all at the same or maybe do 2 in parallel to lower it or series to raise it if need be.
But for example the Fountek NeoCD3.0 is a 7 Ohm tweeter, will it do much problem since its going to get a little more power than anticipated?
What about one like the Aurum Cantus G2Si from partsexpress that is 6 Ohms?
Because that one has 96 dB even though the rest of the specs like Fs are not there
Leo
Okay, impedance is not the same thing as resistance. Resistance is simply the resistance of the coil using a DC voltage. Impedance is the resistance of the coil at frequency. The system impedance plots (yellow curve) tells the story. I used a Zobel network to flatten the impedance across the spectrum. It is fine for your amp, actually, it is a very good curve.
I am liking the G2Si better than the Fountek for its higher SPL and flat response. I just wish I had a real plot of the Peavey driver to be sure that the two match well. It may be a very good combination, but the real way to do this is to build a prototype cabinet and then do extensive testing with a mic and a computer program like HolmImpulse to capture the on and off-axis responses and phase. Then you import that data into a good crossover design package and design a very good crossover.
We don't have that luxury, but I think the design I posted would get you a very nice loudspeaker.
Hi,
So, keep it strictly as woofer with 200...400Hz crossover to the Audax Midrange. In that range the TS Parameters should dominate the response.
Ciao T
So, keep it strictly as woofer with 200...400Hz crossover to the Audax Midrange. In that range the TS Parameters should dominate the response.
Ciao T
What's the point?
The Peavey F3 is 125 Hz. If the Audax F3 is 190 Hz. Crossed at 200 Hz, or even 400 Hz, the Peavey is doing virtually no work in the system. Actually, it is worse than that.
An externally hosted image should be here but it was not working when we last tested it.
The red trace is the Peavey. The yellow trace is the Audax.
The Peavey makes a better wide range mid than the Audax!
All you can do is call. The official part number is 1502-8.
I tried everything I can think of to search for a published frequency response graph and came up dry. Maybe Peavey has one, but they haven't posted it.
The only clue I have seen is the frequency range of 40 to 2 kHz, which tells me that it probably rolls off before 2 kHz.
So, that would suggest that the crossover point should be below 2 kHz (1.2 to 1.5 kHz seems ideal), which seems to bring us back to either a very expensive ribbon like the Aurum Cantus G1 ($425 each) or some kind of horn/compression driver.
B&C makes some good compression drivers at reasonable prices, but finding a good horn is expensive (more than the G1 costs). You can buy cheap horns, but the sound is pretty bad.
I'm not an expert on horns, so maybe someone else here could make some suggestions.
I will say that any 2-way speaker design is going to be a whole lot simpler than a 3-way design, so keeping it a 2-way will save money and time.
I think that you can possibly squeak the Fountek NeoCd2.0M a little lower in crossover frequency, but you must increase the order of the crossover to something like 4th order:
An externally hosted image should be here but it was not working when we last tested it.
This is very doable as you can see without too much extra components (need one extra cap and inductor on the tweeter). The idea is to protect the ribbon tweeter from too much low frequency by increasing the rate at which the frequency is cut off from 12 dB/octave to 24 dB/octave.
Actually, what the theoretical BssBox Pro plot does not show is the actual upper end of the Audax.
Here is an actual plot of my PR170M0 mounted in a sealed box of about .2 cubic feet. The upper end goes out to about 7+ kHz. The lower end is probably modeled correctly in BassBox Pro.
This illustrates the importance of taking actual measurements to do the design.
An externally hosted image should be here but it was not working when we last tested it.
I'd love to see the actual plot of the Peavey in a small sealed cabinet. That would make work a lot easier.
Hi,
Well, not sure what boxes you are modelling.
If I use Winisd to sim the Peavey in 150l tuned to 40Hz and then use a nominal 400Hz 1st order crossover to the Audax (with some fudge factor to compensate the fact that TS parameters do not describe the audax well at all above around 250Hz) I get the attached with a system (after XO) f3 of 45Hz. So to me this combo makes a lot of sense.
Ciao T
Well, not sure what boxes you are modelling.
If I use Winisd to sim the Peavey in 150l tuned to 40Hz and then use a nominal 400Hz 1st order crossover to the Audax (with some fudge factor to compensate the fact that TS parameters do not describe the audax well at all above around 250Hz) I get the attached with a system (after XO) f3 of 45Hz. So to me this combo makes a lot of sense.
Ciao T
Attachments
Nice work.
I see your point, but have you investigated the cone excursion for the vented alignment?
The Xmax is only 1.5 mm and when I modeled that driver in a vented enclosure at 40 Hz and 100 Watts and had Xmax exceeded before Fb. In fact, it exceeded Xmax at about 75 Hz.
My box was a 3.5 cubic foot box.
I would not vent the Audax. Any reason why you choose to do that?
Also, what were your box parameters for the Peavey? I would like to see if I get the same results as WinISD.
I would also like to know where Xmax is on your design?
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