With a 1st order highpass, excursion isn't controlled. It just keeps getting higher and higher as the frequency becomes lower, until the acoustic LF rolloff of the driver/enclosure comes in and the overall acoustic roll off transitions to 3rd order causing excursion to drop off with lower and lower frequencies. So essentially the requirement is a driver that has good performance down to its mechanical roll off which is rarely found in a full range driver. In terms of distorted bass coming from the FR driver which is playing the treble, a 1st order highpass is just a little bit better than running no highpass at all.
2nd order maintains constant excursion from 1octave below the crossover point which is probably acceptable if you pick a conservative crossover frequency.
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I think my MA Alpair 7.3/12pw are pretty close to your concept. They use a 1st order PLLXO so need to be biamplified, but are otherwise to the brief.
I do wish I had the skill to develop a passive, speaker-level XO for them.
Alpair 7.3eN/12pw WAW build
I do wish I had the skill to develop a passive, speaker-level XO for them.
Alpair 7.3eN/12pw WAW build
I don't really see the point of using two FR drivers. If you are going to cross, then why not use a driver designed for the range you want?
If you cross low, then use a real woofer the the bottom end, if you cross high (or augment) use a real tweeter for the highs. A fullrange driver will have compromises at the ends of its bandwidth to keep it full range. When that range isn't needed, then the driver can better suit either the high or the low end of the spectrum.
I see that as the main argument against using 2 FR speakers. Use just one, then fill in where it can't reach with a driver suited to the task.
If you cross low, then use a real woofer the the bottom end, if you cross high (or augment) use a real tweeter for the highs. A fullrange driver will have compromises at the ends of its bandwidth to keep it full range. When that range isn't needed, then the driver can better suit either the high or the low end of the spectrum.
I see that as the main argument against using 2 FR speakers. Use just one, then fill in where it can't reach with a driver suited to the task.
The way Dave described it to me is that he wanted to use two drivers with very wide bandwidths (in my case from the same family) to provide similar/complementary tonal characteristics and dynamics. I suggested using a Dayton 8" sub I had lying around for 300hz down, but he said using an "atmosphere generator" like that wouldn't integrate well with the speedy 7.3. I trusted him, and the Alpairs do integrate amazingly well.
Two widebanders also allows for a lot of flexibility with crossover points. The 7.3 can dig down towards 50hz (according to Dave), while the 12pw can get up to 10khz. Many options, even with 1st order crossovers.
Two widebanders also allows for a lot of flexibility with crossover points. The 7.3 can dig down towards 50hz (according to Dave), while the 12pw can get up to 10khz. Many options, even with 1st order crossovers.
I just read the thread and it sounds like they turned out very well. Certainly would be interested to hear the result if you do pursue a speaker based XO.
Over here, the only highish Qts 15" driver I could find was in fact a FR.
Response was not bad, but being a 15", beaming was quite intense.
Meant to use it with the W8-1772 anyway. which for an 8" driver has minimal beaming (but of course can't completely beat the laws of physics!)
So, off I went using a 15" FR and a 8" FR drivers.
The XO is an ever evolving thing, as the W8 is not the easiest to match with others.
Still looks alright, me thinks!
Response was not bad, but being a 15", beaming was quite intense.
Meant to use it with the W8-1772 anyway. which for an 8" driver has minimal beaming (but of course can't completely beat the laws of physics!)
So, off I went using a 15" FR and a 8" FR drivers.
The XO is an ever evolving thing, as the W8 is not the easiest to match with others.
Still looks alright, me thinks!
I've liked the sound of speakers who's first cross is nicely below 1K; 800, 500, 300, 100 etc.
Being older, I cant hear much above 10K anymore so that's where (above 10k...) I'd make my next cross, if the sonics I cant hear make an audible difference to those I can; some say they do.
I'm hung up on that low crossover point - many others arent. Maybe that's one reason why "FR" for the top isnt seen so much. It's perfectly fair to trade lack-of-beaming for crossovers at higher frequencies than what I like. I'll just sit at the apex of my beams triangle intersection - and enjoy that low 100Hz crossover - along with all the phase linearity a point source FR has to offer. That's just me and the tradeoff I'm willing to make.
Being older, I cant hear much above 10K anymore so that's where (above 10k...) I'd make my next cross, if the sonics I cant hear make an audible difference to those I can; some say they do.
I'm hung up on that low crossover point - many others arent. Maybe that's one reason why "FR" for the top isnt seen so much. It's perfectly fair to trade lack-of-beaming for crossovers at higher frequencies than what I like. I'll just sit at the apex of my beams triangle intersection - and enjoy that low 100Hz crossover - along with all the phase linearity a point source FR has to offer. That's just me and the tradeoff I'm willing to make.
The Alpair 12pw was supposed to be more of a pure woofer, but ended up being more of a wide band driver that could produce bass. It was sort of a replacement for the EL166 6.5" woofer that was manufactured for Creative Sound Solutions (before Bob sold it) by Mark Audio. Dave and Chrisb build a large MTM with this woofer and the Fostex FF85k, which turned out to be an impressive performer. The second revision of this design used the A12pw woofer, because the El166 was OOP, and the then new A7p for the mid-tweet.
There was a single 12pw + A7p design floating around in a stand mount box at the same time, but I don't think Chrisb ever build this.
jeff
I have played on both sides of WAW. 3" with proper woofer is the best combo. 3Fe22 is a good candidate.
Let me explain why.
8" FR + Supertweeter ( Say a SEAS FR22Z + ribbon) actually sounds pretty good but the bass is limited because the best xmax you could pretty much coax out of them is 3mm. A real woofer 8" can have more than 5mm. And to get the bass right, the cabinet you require is huge.... Full scale floor stander..
8" woofer + 3" 3Fe22. 3Fe22 and I believe many other 3" can match a done tweeter out there. Something that you don't quite expect. the off axis response for 3FE22 is not necessarily worse than many dome tweeter out there. If you still want even more treble. add in a simple half inch tweeter pointing back or top NEVER front.
I have overlap speakers before and I don't quite much. Simply because the sound from one speaker that is not exactly the same in phase etc essentially becomes the "distortion " for the other... Which is why you don't add a tweeter to a full range in the front. To the top and back the delay is sufficient that the brain recognises it as an echo and reverb.
Oon
Let me explain why.
8" FR + Supertweeter ( Say a SEAS FR22Z + ribbon) actually sounds pretty good but the bass is limited because the best xmax you could pretty much coax out of them is 3mm. A real woofer 8" can have more than 5mm. And to get the bass right, the cabinet you require is huge.... Full scale floor stander..
8" woofer + 3" 3Fe22. 3Fe22 and I believe many other 3" can match a done tweeter out there. Something that you don't quite expect. the off axis response for 3FE22 is not necessarily worse than many dome tweeter out there. If you still want even more treble. add in a simple half inch tweeter pointing back or top NEVER front.
I have overlap speakers before and I don't quite much. Simply because the sound from one speaker that is not exactly the same in phase etc essentially becomes the "distortion " for the other... Which is why you don't add a tweeter to a full range in the front. To the top and back the delay is sufficient that the brain recognises it as an echo and reverb.
Oon
Should be noted that one of these “FRs” is actually a midbass with good HF extension. The other a FR with good top & mid, but due to size limited in the ability to move the air a larger driver provides. The family similarity in voicing makes for a fairly easy blending of the 2 drivers with a wide range of XO points possible — we used 250 Hz.
Atmosphere generator is a term manufacturers use to describe subWoofers. Most do not go high enuff to make for a decent blend, so one gets a voicing discontinuity at the XO.
With our WAW builds LF driver extension up top reached from 1.7kHz up to 10kHz (the 4” with better dispersion than the 6.5”, but we used a pr (or in one case 2 pair) mounted on the sides of the box.
dave
It is impossible to get a tweeter within the ideal quarter-wavelength centre-to-centre distance needed for a seemless physical configuaration.
dave
And to answer the title question there are at least a few commecial speakers that use FRs as mids, and some that use them as midBass drivers in a 2-way.
dave
dave
Swapped out for (1st) A7 MAOP and then A7.3eN.
The same ML-TL for the bass as our MTM (2x the crossection for 2 drivers) and a 1kHz passive XO.
dave
Full-range
Lower
And
New
Technology
Upper
Range.
FLANTUR ... As a current user of a "vintage" FR driver, I abhor my twelve-inch FR driver shooting everything past 3K into my knees.
Audio Nirvana 15 classic ferrite
Aurum Cantus G1???????
------------------------------------------------------------------Rick..........
Lower
And
New
Technology
Upper
Range.
FLANTUR ... As a current user of a "vintage" FR driver, I abhor my twelve-inch FR driver shooting everything past 3K into my knees.
Audio Nirvana 15 classic ferrite
Aurum Cantus G1???????
------------------------------------------------------------------Rick..........
OK. thanks need to study that.
I wonder if any company has tried wideband coaxial where most frequency response lies with woofer ?
regards
Thanks! 🙂
You'd be quite surprised.
There are 2 layers of granite, 2 layers of honeycombed aluminum and two layers of plywood.
Even with all that, each one weighs about 25kg... drivers included.
The layering of materials absorbs any kind of vibration.
I can play really loud, put a finger on the baffle, and there's no vibration.
Keeps distortion very low.