The Seas CA26RE4X and the 27TBCD/GB-DXT look like candidates for a possible 2way if crossed at 1300-1400hz
Has anyone thoughts on this combo.
I always liked the sound of a 10" two way for classic rock and these drivers might make a nice larger stand mount/ bookshelf type speaker.
Maybe a variovent type enclosure to keep volume reasonable.
I would assume a higher order crossover would be required but I could be wrong.
Thanks !
John
Has anyone thoughts on this combo.
I always liked the sound of a 10" two way for classic rock and these drivers might make a nice larger stand mount/ bookshelf type speaker.
Maybe a variovent type enclosure to keep volume reasonable.
I would assume a higher order crossover would be required but I could be wrong.
Thanks !
John
I am building one now, a good 2 way will sound very good, look at 2 way from AudioKinesis amd from Proac.
My design relies on similar concept from AudioKinesis, horn top end and 10" driver Alnico(fairly old from Japan) I bought 2nd hand, sounds pretty good compared with other drivers.
Cheers.
My design relies on similar concept from AudioKinesis, horn top end and 10" driver Alnico(fairly old from Japan) I bought 2nd hand, sounds pretty good compared with other drivers.
Cheers.
johnmark said:
Hi John, I'm John too.
There are a couple of things that come to mind: First, I would avoid a crossover point in the 1.3k area as it is in the range where our hearing is most sensitive.
Second, I would think twice about crossing a 10" that high.
Third, the tweeter you've picked will not cross that low.
Hi
The Bad
The Le is high... (3 mH due to 4 layer VC) and will be a problem if used in a higher order filter at 1.3KHz. You could zobel, but would have to model it to be sure for 4th order acoustical. You would have to use a special tweeter at 1.3 KHz.
The Good
But you could try it without using a LF crossover. Offaxis and onaxis responses are almost on top of each other which is great for matching the dome tweeter directivities at the Xover.
You could use a 2nd order HP for tweeter to match woofers natural 2nd LPF. Now you could cross the tweeter a little higher at around 2 KHz or so.
Mms... is low
Bl... is high
Sensitivity is high
No Ugly
edit > not for super Hi Fi as some woofer breakup's around xover
but could rock on pop music.
The Bad
The Le is high... (3 mH due to 4 layer VC) and will be a problem if used in a higher order filter at 1.3KHz. You could zobel, but would have to model it to be sure for 4th order acoustical. You would have to use a special tweeter at 1.3 KHz.
The Good
But you could try it without using a LF crossover. Offaxis and onaxis responses are almost on top of each other which is great for matching the dome tweeter directivities at the Xover.
You could use a 2nd order HP for tweeter to match woofers natural 2nd LPF. Now you could cross the tweeter a little higher at around 2 KHz or so.
Mms... is low
Bl... is high
Sensitivity is high
No Ugly
edit > not for super Hi Fi as some woofer breakup's around xover
but could rock on pop music.
A number of classic AS speakers that originated in New England were 2-ways with 10 inch woofers. Advent, KLH, AR, etc...
Typically, they had simple 1st order inductors on the woofers crossed in the 1khz range.
You'll need a tweeter with a very low Fs and high power handling that will stand up to the rock, which I suspect will be played on the loud side.
Typically, they had simple 1st order inductors on the woofers crossed in the 1khz range.
You'll need a tweeter with a very low Fs and high power handling that will stand up to the rock, which I suspect will be played on the loud side.
Interesting design. I have also that kind of speaker in my mind.
I think 10" would be too big if driver isn't very low mass by cone. 8" would give much more alternatives. How about nice 8" driver which has smooth responce to even 5000 Hz? At least 4000 Hz so it could be crossovered in area where ear isn't so sensitive.
Good:
SPL match, tweeter vs. mid, easier crossover ?
not much compression in low frequensies
"warm" sound, bold lower midrange ? (suitable for old rock etc)
2-way design would be _near_ full range (30-20000 Hz)
2-way is always good design
Bad:
loss of detail in mid range?
I have heard Acapella High Harlekin which is large 2-way with dome tweeter and about 10" bass/mid in large closed enclosure. Bass is very solid, not boomy even a hint but go low when asked. Cabinet may be like 50 litres.
I think 10" would be too big if driver isn't very low mass by cone. 8" would give much more alternatives. How about nice 8" driver which has smooth responce to even 5000 Hz? At least 4000 Hz so it could be crossovered in area where ear isn't so sensitive.
Good:
SPL match, tweeter vs. mid, easier crossover ?
not much compression in low frequensies
"warm" sound, bold lower midrange ? (suitable for old rock etc)
2-way design would be _near_ full range (30-20000 Hz)
2-way is always good design
Bad:
loss of detail in mid range?
I have heard Acapella High Harlekin which is large 2-way with dome tweeter and about 10" bass/mid in large closed enclosure. Bass is very solid, not boomy even a hint but go low when asked. Cabinet may be like 50 litres.
An externally hosted image should be here but it was not working when we last tested it.
I have used 10inch midrange and broken all those rules with out ruining the soung BUT best suited to Rock&Roll , I crossed at 4k and as these were party speakers no-one ever noticed the defects off axis, I have a very similar set with 8inch drivers crossed at 3k and both have very similar sound signatures, MTM format so this may not apply to single driver boxes.
http://www.flickr.com/photos/25510659@N07/2431709093/
Very high "Q" drivers 0.86 and that is an aperiodic box of 120litres never got around to painting them
http://www.flickr.com/photos/25510659@N07/2431709093/
Very high "Q" drivers 0.86 and that is an aperiodic box of 120litres never got around to painting them
All good points.....
Passive xover might be a challenge.
If I can get my hands on the data files for these drivers I could plug into a simulator and play with responses first. I wonder if Seas has data files to share?
Otherwise I could start by playing with an adjustable active xover and at least try out a few xover points. Sure would be easier to go active.
John
Passive xover might be a challenge.
If I can get my hands on the data files for these drivers I could plug into a simulator and play with responses first. I wonder if Seas has data files to share?
Otherwise I could start by playing with an adjustable active xover and at least try out a few xover points. Sure would be easier to go active.
John
World Audio Design has a pair of aperiodic kits that use a 10" SEAS & tweeter. Scott and i did up an alternate Classic TL enclosure.
http://wduk.worldomain.net/acatalog/SpkrKits.html
dave
http://wduk.worldomain.net/acatalog/SpkrKits.html
An externally hosted image should be here but it was not working when we last tested it.
dave
I bet that would sound good in a large TL
Looks like they use the same 10" Seas woofer that I was considering, but use a standard 29tff tweet instead of the DXT.
Crossover looks to be a little higher than I was thinking, but they have obviously spent some time listening and tweaking it.
Would it be worth starting over with the DXT tweeter ?
What would I gain?
John
Looks like they use the same 10" Seas woofer that I was considering, but use a standard 29tff tweet instead of the DXT.
Crossover looks to be a little higher than I was thinking, but they have obviously spent some time listening and tweaking it.
Would it be worth starting over with the DXT tweeter ?
What would I gain?
John
johnmark said:
johnmark said:
Not sure, but I think this is the woofer, 25F-EW
http://www.madisound.com/catalog/product_info.php?cPath=45_228_258&products_id=817
http://www.madisound.com/catalog/product_info.php?cPath=45_228_258&products_id=817
I like how this driver can be used without a crossover. The natural roll off works for me. Just blend an appropriate tweeter and your done. I wish it was 92 or 93 db tho.
I like how this driver can be used without a crossover. The natural roll off works for me. Just blend an appropriate tweeter and your done. I wish it was 92 or 93 db tho.
planet10 said:
Re: World Designs WD25A ,pretty much describes what I had in mind in post#4 in this thread. Luckily you posted this link, because I thought I was going to get flak for suggesting no Xover for the woofer and crossing around 2KHz.
I'm thinking this particular woofer would be best suited for bass reflex, rather than aperiodic or TL, being Qts is somewhat low for those other things.
ttan9 mentions AudioKinesis. Their Planetarium uses a TD12M mated to the DDS waveguide. Earl Geddes uses a 10" driver and 10" waveguide in his Nathan and 12" and 12" waveguide in his Abbey. The trick is being able to find an appropriate high frequency option to get down low enough so you can cross the woofer within your off axis goals, and still is able to meet the required output levels when crossing low. Luckily as your woofer size goes down, it's usable high end goes up and you can go with a smaller waveguide. It typically works out that a waveguide the same diameter as the woofer is quite appropriate. If you don't have wide off axis requirements you can cross even higher. Keep in mind though that the off axis power response will still have some effect on the perceived on axis sound though.
We use the TD10M crossed about 1800hz to the NeoPro5i ribbon in these MTM's here with good results.
We have people using TD15M's crossed at around 1000hz to compression drivers on waveguides, large ribbon drivers, etc as well. In the mains for a front of house system below we use the BMS 1.4" coax compression driver on the XT1464 horn with the pair of TD15M's. The crossover is about 750hz on these.
One of the biggest factors in any of these systems to work well is going to be a woofer has flat response and is clean and breakup free to a bare minimum of one octave above the xover point. This means very low inductance woofers to get the response flat to these higher frequencies. You really don't want to deal with any inductive rise below your xover frequency. In most drivers, as the coil moves the core is going to change. At rest and on the inward stroke it is acting as a purely iron core inductor. As it moves outward past the end of the pole it begins to operate as an air core. So what you have is essentially lower inductance on the outward stroke than on the inward. The CA26RE4X has 3mH inductance at rest. On the outward stroke it may drop significantly and this will change the response curve based on the driver position. This is the biggest issue in terms of distortion created by the motor of the driver. You really want to cross before the inductive rise begins to take effect.
The way to take care of this is to lower absolute inductance, meaning the xover point can be higher before these effects. In addition you want to linearize inductance so it remains the same at all points throughout the travel of the driver. This is what the TD drivers do with the full copper sleeve, and that is why those like Duke at AudioKinesis are using them. The Lambda motor paper is here if you want to read the details.
http://www.aespeakers.com/Lambda001-1.php
In addition to the motor issues, any cone breakups you really want to be 48dB down or they will cause some audible effects. You can EQ down bumps in the response, but breakups cause a resonance. EQing them down or adding a notch filter will change the level, but won't get rid of the resonance. Keep in mind that the resonance will have effects with respect to time as they don't instantly disappear. Pay close attention to any sharp peaky things in the impedance curve in addition to sharp bumps in the response curve of the drivers. Drivers like the TD series are very good in this regard. The TD15M for example is flat and breakup free to as high as 4KHz. The TD12M and TD10M have similar properties. We go through lots of hand coating on the surrounds, cone treatment, spider treatment on some drivers, etc to damp these resonances.
John
We use the TD10M crossed about 1800hz to the NeoPro5i ribbon in these MTM's here with good results.
We have people using TD15M's crossed at around 1000hz to compression drivers on waveguides, large ribbon drivers, etc as well. In the mains for a front of house system below we use the BMS 1.4" coax compression driver on the XT1464 horn with the pair of TD15M's. The crossover is about 750hz on these.
One of the biggest factors in any of these systems to work well is going to be a woofer has flat response and is clean and breakup free to a bare minimum of one octave above the xover point. This means very low inductance woofers to get the response flat to these higher frequencies. You really don't want to deal with any inductive rise below your xover frequency. In most drivers, as the coil moves the core is going to change. At rest and on the inward stroke it is acting as a purely iron core inductor. As it moves outward past the end of the pole it begins to operate as an air core. So what you have is essentially lower inductance on the outward stroke than on the inward. The CA26RE4X has 3mH inductance at rest. On the outward stroke it may drop significantly and this will change the response curve based on the driver position. This is the biggest issue in terms of distortion created by the motor of the driver. You really want to cross before the inductive rise begins to take effect.
The way to take care of this is to lower absolute inductance, meaning the xover point can be higher before these effects. In addition you want to linearize inductance so it remains the same at all points throughout the travel of the driver. This is what the TD drivers do with the full copper sleeve, and that is why those like Duke at AudioKinesis are using them. The Lambda motor paper is here if you want to read the details.
http://www.aespeakers.com/Lambda001-1.php
In addition to the motor issues, any cone breakups you really want to be 48dB down or they will cause some audible effects. You can EQ down bumps in the response, but breakups cause a resonance. EQing them down or adding a notch filter will change the level, but won't get rid of the resonance. Keep in mind that the resonance will have effects with respect to time as they don't instantly disappear. Pay close attention to any sharp peaky things in the impedance curve in addition to sharp bumps in the response curve of the drivers. Drivers like the TD series are very good in this regard. The TD15M for example is flat and breakup free to as high as 4KHz. The TD12M and TD10M have similar properties. We go through lots of hand coating on the surrounds, cone treatment, spider treatment on some drivers, etc to damp these resonances.
John
MisterTwister said:
There is a big difference between an inductor in series and inductance in the coil. The inductor in series doesn't change. It's core is the same all the times, meaning the inductance doesn't change. The inductance in the driver changes with varied excursion. You could have a coil with 3mH inductance on the inward stroke and .5mH inductance on the outward stroke for example. Model up what the difference in response is and you will see a huge difference. Any time you have these extreme non-linearities distortion skyrockets. As the impedance curve changes wildly, the effects of any passive filters you have in place will also change drastically.
Some will argue that impedance compensation to bring down the inductive rise will correct the issue. However, the impedance compensation circuit has to be applied based on the values of the original impedance curve. As the original impedance curve changes due to inductive changes, the filter no longer works properly. It may work ok at low excursions, but higher excursions really mess things up.
As an example, say you are playing a 500hz tone at a given level that doesn't cause much excursion on the driver. It may play fine with relatively low distortion. Now take into account real music. That same tone plays at the same as other tones as well. Take a 20hz tone that causes high excursion on the driver and now play the 500hz tone. The 500hz tone greatly varies based on the excursion created from the 20hz tone.
Lowering inductance, to put these issues out of the usable band is critical. Linearizing inductance so it is the same at all points throughout the travel is even more important.
John
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