I was looking to build a simple 2-way speaker similar to the BR-1 kit on Parts Express, but instead of the 6.5" woofer, use the 10" DC250-8 in a sealed box. I am familiar with the 6.5" DC160-8 and while I think it is a quality woofer, I am looking for a bit more bottom end without porting (for better transient response).
Looking at the DC250-8's response graph, it seems a good crossover point would be around 2khz. However I know it would be advisable to keep the center of the drivers within a wavelength of each other (13560/2000 = 6.78") that would be physically impossible at that crossover point (Minimum ~7.5"). However, if I used a crossover of 1.5-1.8khz I would have enough spacing to make it work and I think these drivers could cross over in that range assuming I used a 2nd-3rd order.
My question is, are there other potential issues I am not seeing with this design? I may slant the baffle to account for time delay between drivers as well. I just have not seen many 2-way designs with a 10" woofer. I assume this is generally because the cross over doesn't work, but I think it would here.
Please advise me for other problems I may not be accounting for or for other suggestions all together.
Thanks
Looking at the DC250-8's response graph, it seems a good crossover point would be around 2khz. However I know it would be advisable to keep the center of the drivers within a wavelength of each other (13560/2000 = 6.78") that would be physically impossible at that crossover point (Minimum ~7.5"). However, if I used a crossover of 1.5-1.8khz I would have enough spacing to make it work and I think these drivers could cross over in that range assuming I used a 2nd-3rd order.
My question is, are there other potential issues I am not seeing with this design? I may slant the baffle to account for time delay between drivers as well. I just have not seen many 2-way designs with a 10" woofer. I assume this is generally because the cross over doesn't work, but I think it would here.
Please advise me for other problems I may not be accounting for or for other suggestions all together.
Thanks
With a woofer that large you want a fairly low XO point, unless you are fine with a big hole in the upper midrange.
Typically one would look at a waveguide top end with an XO of about 1 kHz, or the approach i would take is to use a good fullrange as a midTweeter with XO 300-450 Hz or so (a WAW).
dave
Typically one would look at a waveguide top end with an XO of about 1 kHz, or the approach i would take is to use a good fullrange as a midTweeter with XO 300-450 Hz or so (a WAW).
dave
Off the top of my head,
Generally, a 10" mid-woofer will start beaming at 1,500 to 1,600 Hz which will create off-axis issues and other bumps in the road. For this reason, you generally don't see properly made speakers with dome tweeters that use 10 inch woofers.
I own a "10" two-way" but it uses a compression driver/horn combo that crosses over low at 1,450 Hz with a fairly steep crossover filter to drive the natural breakup modes down deep. It works very well but be aware that tweeters that can operate without gross distortion or failure tend to be not that common. I think there are one or two dome tweeters that will do it, maybe a few AMTs and of course, compression drivers and horns.
There is a company in Minnisota that rolled out a dome tweeter that will do 1,500 Hz--forgot the name of the company but I know the state!
Now if you want to use a tweeter that has a lower limit of 2KHz, the largest you can go with a woofer without creating too many problems is around 8 inches.
Basically, the larger the woofer the lower it will go (within reason) but that limits the high frequencies. For example, you could use a 12 inch woofer but they usually require a crossover point of around 1,250Hz (more or less) which require quite the stout "tweeter" if you will. You are firmly in pro sound AMT and compression driver territory there but it gives you an idea.
Hope that helps--in short, best to use an 8 incher when crossing at 2KHz--good luck!
Generally, a 10" mid-woofer will start beaming at 1,500 to 1,600 Hz which will create off-axis issues and other bumps in the road. For this reason, you generally don't see properly made speakers with dome tweeters that use 10 inch woofers.
I own a "10" two-way" but it uses a compression driver/horn combo that crosses over low at 1,450 Hz with a fairly steep crossover filter to drive the natural breakup modes down deep. It works very well but be aware that tweeters that can operate without gross distortion or failure tend to be not that common. I think there are one or two dome tweeters that will do it, maybe a few AMTs and of course, compression drivers and horns.
There is a company in Minnisota that rolled out a dome tweeter that will do 1,500 Hz--forgot the name of the company but I know the state!
Now if you want to use a tweeter that has a lower limit of 2KHz, the largest you can go with a woofer without creating too many problems is around 8 inches.
Basically, the larger the woofer the lower it will go (within reason) but that limits the high frequencies. For example, you could use a 12 inch woofer but they usually require a crossover point of around 1,250Hz (more or less) which require quite the stout "tweeter" if you will. You are firmly in pro sound AMT and compression driver territory there but it gives you an idea.
Hope that helps--in short, best to use an 8 incher when crossing at 2KHz--good luck!
I'd say a small wideband unit would be the obvious choice here. The SB65 unit gets great reviews, and I'm looking forward to trying some out when they arrive here. So long as you're not looking for crazy SPLs, it'll probably work well for you, too.
With some cash to throw around, the high-end tweeters will usually make it down below 1.5kHz. The SB Acoustics TW29B, for instance, has a 600Hz Fs and would probably manage a fairly low crossover. They've also done some waveguide-loaded versions.
Finally, compression drivers w/horns. They do have advantages:
- Controlled directivity
- Very high sensitivity
- Fairly high power handling
The major downside is the difficulty of implementation. They typically require more work at the crossover, and I'd recommend a measurement mic etc for really getting them dialled in.
Chris
With some cash to throw around, the high-end tweeters will usually make it down below 1.5kHz. The SB Acoustics TW29B, for instance, has a 600Hz Fs and would probably manage a fairly low crossover. They've also done some waveguide-loaded versions.
Finally, compression drivers w/horns. They do have advantages:
- Controlled directivity
- Very high sensitivity
- Fairly high power handling
The major downside is the difficulty of implementation. They typically require more work at the crossover, and I'd recommend a measurement mic etc for really getting them dialled in.
Chris
This might give you some ideas, it uses the DC28F and DC250 woofer:
E’couter | Parts Express Project Gallery
I've no idea how it sounds, of course but I'd be reluctant to push the DC28 quite that hard.
On a budget, you could also think about using a 2.5" VIFA TC-7 full range instead of a dome tweeter: Zaph gave it an excellent review and it has been used with 6.5" and 8" woofers in two way designs. The TC-7 has a higher dB output than other similar drivers.
HTH
Geoff
E’couter | Parts Express Project Gallery
I've no idea how it sounds, of course but I'd be reluctant to push the DC28 quite that hard.
On a budget, you could also think about using a 2.5" VIFA TC-7 full range instead of a dome tweeter: Zaph gave it an excellent review and it has been used with 6.5" and 8" woofers in two way designs. The TC-7 has a higher dB output than other similar drivers.
HTH
Geoff
What about Seas 35mm dome from the A26 kit? 1500hz xo no problem.
SEAS A26 Kit
SEAS The Art Of Sound Perfection
TWEETERS
SEAS A26 Kit
SEAS The Art Of Sound Perfection
TWEETERS
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Even if you have a dome tweeter that can handle a 1200Hz cross over (and there are many that can do that), it's still a bad idea to mate it with a 10" mid-bass. At 1200Hz a 10" driver will have a beam width of approximately 90 degrees. The tweeter will be close to 180 degrees. If your crossover is designed to have flat response on axis, the off axis response will have a large discontinuity (NOT flat) off axis. Since much of what you hear is reflected power the speaker will sound "wrong". You can't EQ it right either.
Generally if you want a 2 way with a big woofer you'll be forced into using a waveguide (and probably a compression driver) to get the beam width of the woofer and tweeter to match at the cross over point. It's not super hard to design such a system, but it's a bit different than just a standard cone+dome design (mostly because the acoustic centers of the two drivers will be far apart, so some delay will be necessary). It's much easier if done actively rather than passive, but that's another can of worms to open ;-)
If you really don't want to go the waveguide route, try using a full range driver like one of the Vifa/Peerless TG9 variations plus the 10" woofer and cross over at 350Hz or so. It'll probably sound great and the cross over should be fairly easy to design. Just be aware that it won't go very loud (but maybe loud enough for what you want).
Generally if you want a 2 way with a big woofer you'll be forced into using a waveguide (and probably a compression driver) to get the beam width of the woofer and tweeter to match at the cross over point. It's not super hard to design such a system, but it's a bit different than just a standard cone+dome design (mostly because the acoustic centers of the two drivers will be far apart, so some delay will be necessary). It's much easier if done actively rather than passive, but that's another can of worms to open ;-)
If you really don't want to go the waveguide route, try using a full range driver like one of the Vifa/Peerless TG9 variations plus the 10" woofer and cross over at 350Hz or so. It'll probably sound great and the cross over should be fairly easy to design. Just be aware that it won't go very loud (but maybe loud enough for what you want).
What hweb says.
As chance would have it, there's a current thread with a long-running discussion of all possible variations of exactly this kind of thing here:
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
As chance would have it, there's a current thread with a long-running discussion of all possible variations of exactly this kind of thing here:
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
I played around with this idea earlier in the year and was disappointed with the results. I know it's pushing physics, but I felt like trying anyway, given modern tweeters being able to cross lower.
I used a Dayton DSA270-8 and RST28. The in-baffle measurements of the RST28 showed response down to 850Hz, falling quickly after that. The DSA270 was smooth out to 2K or so, and that made me think it was doable. In reality, the tweeter wasn't sensitive enough to keep up with the woofer (despite being 2dB more efficient, per the data sheet) and, even though it didn't show in the measurements, it seemed there was a hole in the midrange when listening. I will keep playing with it, but I can see it will be a challenge to make it sound right. I think I crossed at around 1,300Hz. Don't remember the orders.
I've also considered using a Wavcor TW030 tweeter in a waveguide. Haven't had time to experiment lately.
I used a Dayton DSA270-8 and RST28. The in-baffle measurements of the RST28 showed response down to 850Hz, falling quickly after that. The DSA270 was smooth out to 2K or so, and that made me think it was doable. In reality, the tweeter wasn't sensitive enough to keep up with the woofer (despite being 2dB more efficient, per the data sheet) and, even though it didn't show in the measurements, it seemed there was a hole in the midrange when listening. I will keep playing with it, but I can see it will be a challenge to make it sound right. I think I crossed at around 1,300Hz. Don't remember the orders.
I've also considered using a Wavcor TW030 tweeter in a waveguide. Haven't had time to experiment lately.
I WOULD NOT build that design. The designer said he placed 2 higher power ceramic resistors in parallel with the woofer to have higher power handling.
This is a lot of unsafe practice, as those resistors across a woofer may become a fire hazard. Secondly, they really won't increase power handling, but dissipate more power as heat.
Now- I've been known to suggest a 40-50 ohm resistor across a woofer of the 25-50W variety if the impedance spike causes a bump in the response as this will reduce it. However, the designer for E'couter used 2x 40 ohm resistors paralleled. This means it is a 20 ohm load across the woofer. This, IMO, is too low and will shunt a lot of current.
The comments in the writeup basically equate the designer herein to not really understanding xovers.
Later,
Wolf
This is a lot of unsafe practice, as those resistors across a woofer may become a fire hazard. Secondly, they really won't increase power handling, but dissipate more power as heat.
Now- I've been known to suggest a 40-50 ohm resistor across a woofer of the 25-50W variety if the impedance spike causes a bump in the response as this will reduce it. However, the designer for E'couter used 2x 40 ohm resistors paralleled. This means it is a 20 ohm load across the woofer. This, IMO, is too low and will shunt a lot of current.
The comments in the writeup basically equate the designer herein to not really understanding xovers.
Later,
Wolf
"Your scientists were so preoccupied with whether they could, they didn't stop to think if they should."
I would second the use of a cone mid/tweeter ( just use a small full range cone, I'd recommend woven glass fibre ), you can use a first order crossover and have free rain to chose/experiment with your crossover point. I used a cone " tweeter " this way in my box in a box speakers and I'm well chuffed with them. Hi fi world magazine did a long series of articles about their WD25A, and how they matched a 10" driver with a dome tweeter, somewhere around 2007.
depends on how you define good and whats important for the user.
there something special with a 10" bass that makes it desirable in a 50l, compared to a 2*6,5 in my opinion usually sounds thinner and smaller. it could be a baffle step issue in slim towers more than the total driver cone area but in my experience a 10" is more like 2*8, while 2*6,5 is more like 1*8 if we talk bass. assuming everything else is static of course the midrange is easier to make good in a 6,5. two-way will always be compromise no matter the size. i would easily build another 10" Dynaco A25 replica or the new Seas A26 kit some day. Its all about finding the right matching and ambition based on your need.
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Peerless by Tymphany TG9FD-10-04 3-1/2" Glass Fiber Cone Full Range
Cross at 500hz
The scan-speak 10/f was modeled from this driver
Cross at 500hz
The scan-speak 10/f was modeled from this driver
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of course im talking about a decent 10" not any.
I think this is what I tried to say as well and I guess logic indicate the same can be said about sensitivity in the lower ranges, a 10" can easily be 6dB more sensitive given the same cone material and motor and therefore a lot cheaper solution for good dynamics in a small box rather than 4x6,5.
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