Thanks for the very clear update and rundown, Lynn. With your permission, I'll link to your current LTO description in the very first post.
I'm surprised that you were able to get where you need to with electrical crossovers at the same point - 700Hz. In my A5 there was such a rising response from the woofer that I had to electrically cross it much lower. I.E., i had to spread the electrical points to get the acoustic points to sum.
It's nice that you did not have to do the frequency spread that I did. Your LTO box size is also surprisingly small, which is a great thing for living rooms.
To RockLeeEV:
I'm still going to use the RAAL Lazy Ribbons for my own personal system. For one thing, I own them; Alexander was kind enough to send me the first prototypes he built, and I'm certainly going to use them. They sound absolutely wonderful and are a superb match for the Altec/GPA 288 and Radian 745Neo compression drivers. Although they are pricey, they are in a different league than the standard RAAL - much more dynamic, and do not need in-band equalization. Cross them over with a 3rd or 4th-order highpass, and you're good to go.
I also found out that typical (non-RAAL) ribbons are not such a good dynamic match for compression drivers - you wouldn't think that a ribbon crossed over at 7 to 10 kHz would need much in the way of dynamics, but it's audible as dynamic flattening and a certain lack of tonal vividness right at the top of the spectrum. Integrating a conventional ribbon with a small-format compression driver might work out better, since they don't have the seemingly unlimited dynamics of large-format drivers, but then again, small-formats typically make it out to 15 to 20 kHz without any help from supertweeters.
Heil AMT-type drivers are also a good match, with dynamics similar to compression drivers - you just need to use an AMT with efficiency of 99 dB/meter/watt or higher.
The horn supertweeters were more problematic than I expected. Dynamically, yes, they match the large-format driver, but many of them have a sandpapery coarseness to the sound that spoils the effortless silky smoothness of the 288 or Radian 745Neo. In other words, the small-format metal-diaphragm sound comes back - pinched, tight, and harsh. I haven't tried the hard-to-find EV T350 with the phenolic diaphragm; prices in the collector market are as high as a new RAAL Lazy Ribbon, and I'm always reluctant to recommend unobtanium for any project.
The other downside of many horn supertweeters is surprisingly poor dispersion, with beamwidths that don't seem to be any greater than 20 to 30 degrees in the 10 to 20 kHz top octave. Sure, you can throw crazy money at a horn supertweeter and get a Goto or Ales, but the ones I've heard didn't sound any better than the RAAL Lazy Ribbon, and were way more expensive with limited dispersion.
To Corelement: Sorry, I don't have anything to do with the Jamo speakers. I've seen photos of them, but I've never even heard one, so can't comment one way or the other. Olson is a very common name for people of Scandinavian ancestry, and folks from the frozen North seem attracted to audio - the long dark winters, maybe?
To Badman: I avoided horn speakers for decades because I was afraid of going down the rabbit hole on horn design. I didn't really like the sound of commercial horns, and it took a huge amount of research to reach the point of collaborating with JMLLC, Bjorn Kolbrek and Martin to get the sound I wanted. I'm finally out on the other side of that now - the rest of the speaker is a lot easier to design. The resulting AH425 is a nice little bonus for people who are interested in integrating a medium-size horn into their own speaker designs.
The dipole project was waylaid by the ugly necessity of massive equalization; not a problem for the transistor folks, but the amps I enjoy are direct-heated triode and pentode amplifiers with pretty modest power outputs.
I'm still going to use the RAAL Lazy Ribbons for my own personal system. For one thing, I own them; Alexander was kind enough to send me the first prototypes he built, and I'm certainly going to use them. They sound absolutely wonderful and are a superb match for the Altec/GPA 288 and Radian 745Neo compression drivers. Although they are pricey, they are in a different league than the standard RAAL - much more dynamic, and do not need in-band equalization. Cross them over with a 3rd or 4th-order highpass, and you're good to go.
I also found out that typical (non-RAAL) ribbons are not such a good dynamic match for compression drivers - you wouldn't think that a ribbon crossed over at 7 to 10 kHz would need much in the way of dynamics, but it's audible as dynamic flattening and a certain lack of tonal vividness right at the top of the spectrum. Integrating a conventional ribbon with a small-format compression driver might work out better, since they don't have the seemingly unlimited dynamics of large-format drivers, but then again, small-formats typically make it out to 15 to 20 kHz without any help from supertweeters.
Heil AMT-type drivers are also a good match, with dynamics similar to compression drivers - you just need to use an AMT with efficiency of 99 dB/meter/watt or higher.
The horn supertweeters were more problematic than I expected. Dynamically, yes, they match the large-format driver, but many of them have a sandpapery coarseness to the sound that spoils the effortless silky smoothness of the 288 or Radian 745Neo. In other words, the small-format metal-diaphragm sound comes back - pinched, tight, and harsh. I haven't tried the hard-to-find EV T350 with the phenolic diaphragm; prices in the collector market are as high as a new RAAL Lazy Ribbon, and I'm always reluctant to recommend unobtanium for any project.
The other downside of many horn supertweeters is surprisingly poor dispersion, with beamwidths that don't seem to be any greater than 20 to 30 degrees in the 10 to 20 kHz top octave. Sure, you can throw crazy money at a horn supertweeter and get a Goto or Ales, but the ones I've heard didn't sound any better than the RAAL Lazy Ribbon, and were way more expensive with limited dispersion.
To Corelement: Sorry, I don't have anything to do with the Jamo speakers. I've seen photos of them, but I've never even heard one, so can't comment one way or the other. Olson is a very common name for people of Scandinavian ancestry, and folks from the frozen North seem attracted to audio - the long dark winters, maybe?
To Badman: I avoided horn speakers for decades because I was afraid of going down the rabbit hole on horn design. I didn't really like the sound of commercial horns, and it took a huge amount of research to reach the point of collaborating with JMLLC, Bjorn Kolbrek and Martin to get the sound I wanted. I'm finally out on the other side of that now - the rest of the speaker is a lot easier to design. The resulting AH425 is a nice little bonus for people who are interested in integrating a medium-size horn into their own speaker designs.
The dipole project was waylaid by the ugly necessity of massive equalization; not a problem for the transistor folks, but the amps I enjoy are direct-heated triode and pentode amplifiers with pretty modest power outputs.
Last edited:
A little explanation of the name Olson
Yes, we are pretty productive here in Scandinavia when it comes to audio.
Especially Denmark is known for some famous brands in audio, e.g.: Gryphon Audio, Vitus Audio, Dali, Bang & Olufsen, Lyngdorf Audio, Steinway Lyngdorf, Dynaudio, Scan-Speak, Duelund, Audio Technology, Hørning Hybrid
The first practical application of moving-coil loudspeakers was established by Danish engineer Peter L. Jensen and Edwin Pridham, in Napa, California.
I'm proud to be a dane!
We also have a long tradition for DIY here in Denmark, Norway & Sweden. One of the better speaker web-sites on the web might be of your interest: Troels Gravesen.
Lynn, can we have a picture of your prototype speakers? Have you considered using a horn/waveguide in front of the GPA/Altec 416B as in some of the older Altec and JBL speakers?
Lynn ... you mentioned 1" drivers for mids which requires a different AH horn if going that direction or would need an adapter for the 425's. How about manifolding a 425 so you could have the good 2" horn and use two alnico 1" drivers on each horn. Not sure of availability for adapters, eBay? My manifolds are JBL with screw-on 1"; perfect for Atlas alnico's (uncle Paul seemed to do well with them) or flat adapters into manifold can use other drivers (Altec, JBL, etc.).
No clue how they will sound but it's an idea. You would always have tweets for the top end if they suck in higher ranges. I know they would not be a production thing; mainly aimed at us DIYers.
Zene
No clue how they will sound but it's an idea. You would always have tweets for the top end if they suck in higher ranges. I know they would not be a production thing; mainly aimed at us DIYers.
Zene
All, let me clarify last post. Edit didn't take (Pano?) Errors from stupidity abounded.
Lynn ... you mentioned 1" drivers for mids. How about manifolding a 2" horn and use two alnico 1" drivers on each horn? Not sure of availability for them, eBay? My manifolds are JBL with screw-in 1"; perfect for Atlas alnico's (uncle Paul seemed to do well with them).
No clue how they will sound but it's an idea. You would always have tweets for the top end if they suck in higher ranges. I will be using two JBL 2420's. I know they would not be a production thing; mainly aimed at us DIYers. I will be using two JBL 2420's.
Zene
Lynn ... you mentioned 1" drivers for mids. How about manifolding a 2" horn and use two alnico 1" drivers on each horn? Not sure of availability for them, eBay? My manifolds are JBL with screw-in 1"; perfect for Atlas alnico's (uncle Paul seemed to do well with them).
No clue how they will sound but it's an idea. You would always have tweets for the top end if they suck in higher ranges. I will be using two JBL 2420's. I know they would not be a production thing; mainly aimed at us DIYers. I will be using two JBL 2420's.
Zene
You can get an adapter to 1.4" at a reasonable price here:
You can get an adapter to 1.4" at a reasonable price here:
Altec Lansing GPA 21216 21216A Horn Adaptor NEW | eBay
I would think manifolding 2 x drivers really only achieves more power, which you don't need.
If you want to depart further from Lynn's spec and raise the cross over point JBL2420s sound great on 550Hz le Cleac'h horns - possibly 550 horns are more suitable for 1" drivers in general. That's my impression. Bear in mind the plot is with the mic at the horn mouth - purely to show horn/driver interaction - not a standard or comparable method. No flames please.
http://azurahorn.com/JBL2420_on_550.pdf
martin
You can get an adapter to 1.4" at a reasonable price here:
Altec Lansing GPA 21216 21216A Horn Adaptor NEW | eBay
I would think manifolding 2 x drivers really only achieves more power, which you don't need.
If you want to depart further from Lynn's spec and raise the cross over point JBL2420s sound great on 550Hz le Cleac'h horns - possibly 550 horns are more suitable for 1" drivers in general. That's my impression. Bear in mind the plot is with the mic at the horn mouth - purely to show horn/driver interaction - not a standard or comparable method. No flames please.
http://azurahorn.com/JBL2420_on_550.pdf
martin
Truetone ... good find, thx. good find,thx. See you found my error in updated post.
There are lots of possibilities other than the spendy GPA 288's. I do have one 288K but useless except for mono. The main goal is to get below 800Hz crossover point. My new, soon to be turned standard Tractrix flare horn has Fc design of 240Hz so is usable from about 360Hz.
It's name: JAFtractrix horn.
Zene
There are lots of possibilities other than the spendy GPA 288's. I do have one 288K but useless except for mono. The main goal is to get below 800Hz crossover point. My new, soon to be turned standard Tractrix flare horn has Fc design of 240Hz so is usable from about 360Hz.
It's name: JAFtractrix horn.
Zene
i've jumped into this topic at page 112/822, so much lies ahead.
i've a pair of hedlunds that have some great sonic merits and one sonic flaw - horn honk. these were a "gift" and the builder made the wave guides smooth, so there is no stuffing. 2 drivers tried in these produce the same honk. poly fill behind the driver doesn't help.
a pair of harveys had the same flaw until i stuffed a good bit of poly fill in the upper mouth area of each. there was some egg crate stuffing in the harvey's chambers at the sides. don't know if this helped anything. my current belief is that is might not have helped at all.
any ideas as to what might improve the hedlunds?
The only reason manifolding was done "back in the day" was for more power - specifically, theaters with more than 1000 seats (70mm widescreen theaters were really big back then!). There in no improvement in fidelity; manifolds create reflections and roughen the response, so there is no reason at all to use them for home applications.
Compression drivers with 1" exits work fine with LeCleac'h horns, and Martin (Azurahorn) and other vendors sell them. The tradeoff, which is to be expected, is a higher crossover. I would suggest absolutely no lower than 1 kHz, with 1.4 kHz preferable. (Dr. Geddes gets away with 950 Hz, but he knows what he is doing.)
Metal-diaphragm drivers sound really bad if you try and cross them too low - you get the horrible garage-band PA sound if you try that. Plastic-diaphragm drivers tolerate this kind of abuse more gracefully, but I'd still not cross them any lower than 1 kHz - and if you go that low, I'd use a 3rd or 4th-order highpass filter.
The trick with any compression driver is to keep them well away from a too-low crossover - sound quality really deteriorates when you try and "push" them lower than they want to go. This SQ deterioration is much faster than equivalent direct-radiators, and there are a whole lot of PA speakers out there with badly chosen crossover points.
But you won't need a supertweeter, which is a plus.
Last edited:
Yes, we are pretty productive here in Scandinavia when it comes to audio.
Thanks to wikipedia I just learned that Finland does not belong to this agitated group called Scandinavia
As for the Hedlund horns, I have no clue where to start. I'm not a fan of full-range drivers, and particularly not whizzer cones, which have ugly mechanical crossovers in the 3~5 kHz range. A brute-force solution is a passive notch filter tuned to the worst breakups, but that has nothing to do with horn-honk, which is at lower frequencies and is typically a design defect in the horn itself.
The Hedlund looks like a folded horn; the folds create reflections, which in turn create comb-filtering in the frequency response as well ripples in the time domain. In a folded basshorn, a sharp (4th-order) lowpass filter can remove the trouble region, but this option is not present for a full-range system.
The best you can do is measure the system with a digital equalizer and notch-out the (multiple) peaks in the bass range; don't try and equalize the holes in the response, that'll just burn up the driver.
The Hedlund looks like a folded horn; the folds create reflections, which in turn create comb-filtering in the frequency response as well ripples in the time domain. In a folded basshorn, a sharp (4th-order) lowpass filter can remove the trouble region, but this option is not present for a full-range system.
The best you can do is measure the system with a digital equalizer and notch-out the (multiple) peaks in the bass range; don't try and equalize the holes in the response, that'll just burn up the driver.
Last edited:
horns rule if you can "get them right". i don't like the typical "make your ears bleed" type of midrange horn sound. i do like the jbl cd horns. awesome outdoors. need a bit of equalization to get the "life like" midrange sound.
the hedlunds have their moments. but if the source has a lot of "husky" vocals, they amplify this significantly.
i bought the harvey enclosures for $75 from a chap that hated the sound. said they sounded like PA speakers. well after putting a dayton PA130 in them and stuffing the top they sound good. no horn - honk.
hedlunds don't have a top and bottom. this is the disadvantage. "adjusting" the sound with poly foam might not work. i'd prefer a low-tech solution like this but might wind up having to do as you suggest. i do have a frequency counter and an audio generator. a little more "bargain rate" gear and i'm there.
the hedlunds have their moments. but if the source has a lot of "husky" vocals, they amplify this significantly.
i bought the harvey enclosures for $75 from a chap that hated the sound. said they sounded like PA speakers. well after putting a dayton PA130 in them and stuffing the top they sound good. no horn - honk.
hedlunds don't have a top and bottom. this is the disadvantage. "adjusting" the sound with poly foam might not work. i'd prefer a low-tech solution like this but might wind up having to do as you suggest. i do have a frequency counter and an audio generator. a little more "bargain rate" gear and i'm there.
update from the earlier post.
2 of the CSS WR125ST speakers were mounted today. previously i had 1 in each horn ~ 16 ohm load. amp didn't like. so the response wasn't quite authentic.
anyway w/ 8 ohm load and some stuffing at the bottom of the chamber and some behind the drivers, the sound is improved and not really objectionable.
the hedlund is a good cab and these sound better than the BOFU which is too much for the cab, but plays really loud!
Lynn,
I was wondering if you happened to try the B&C DE 5 or De 7 in the same horn profile (scaled down) that you have the mid-range horn on. My thoughts are that horn profiles are good for about a decade. If a 1" will go to about 1200 Hz comfortably, it may struggle above 12Khz or so, which may be a good compromise for a two way, but not if that's the only range its being ask to reproduce.
It might be better to have a half inch (or three quarter )throat driver if it doesn't have to play below 8 k or so. Advantages are simular time domain behavior, simular dispersion, simular efficiency, much lower cost. Probably just as hard to integrate.
Random thought.
Doug
I was wondering if you happened to try the B&C DE 5 or De 7 in the same horn profile (scaled down) that you have the mid-range horn on. My thoughts are that horn profiles are good for about a decade. If a 1" will go to about 1200 Hz comfortably, it may struggle above 12Khz or so, which may be a good compromise for a two way, but not if that's the only range its being ask to reproduce.
It might be better to have a half inch (or three quarter )throat driver if it doesn't have to play below 8 k or so. Advantages are simular time domain behavior, simular dispersion, simular efficiency, much lower cost. Probably just as hard to integrate.
Random thought.
Doug
The old-timers were right about the one-decade range for horns. When you try and "stretch" the frequency range, you lose many of virtues of horns and are left with the faults. When a horn is working too low, the effortless dynamics and vivid tone colors go away, replaced by some pretty ugly artifacts - harshness and gritty sound. All of the stereotypes of bad PA systems - now that "waveguides" are getting popular for home-theater speakers, we're starting to hear that kind of sound in home speakers, too.
A 1" exit compression driver is taking it really easy above 2 kHz - assuming the horn has competent diaphragm loading through the working range.
1.4 kHz - well, now we're needing to be more careful about the crossover, but still do-able if you're willing to mess around with the crossover and do a lot of subjective listening. (Are vocals harsh? Is the midrange congested-sounding on complex recordings? Raise the crossover and see if it goes away.)
1 kHz with 1" exit drivers is only for experts. I wouldn't even try it, and I've been doing crossovers for a while now.
Set aside the economics and look at the physics of the situation. Large-format compression drivers comfortably handle 500 Hz if the horn is large enough (at least 1.4X the size of the AH425, and preferably larger). That makes using 15" drivers very easy, with the efficiency advantages of 15" drivers and resulting increase in headroom in the bass range. If you're bold enough and have enough room, a pair of 15" drivers will truly satisfy - the audio equivalent of a V8 with twin turbos. All the power you could ever want.
Small-format drivers want to be crossed an octave or more higher. That's pretty much what you'd expect based on the differences in size of the diaphragm itself - it's like comparing a 15" bass driver to a 8" bass driver. The dynamic capabilities are very different.
With a crossover falling in the 1.4~2 kHz range, it's kind of the outer limit of what 15" drivers can do. Most 15" drivers have a broad peak around 1.5 kHz, which easily equalized, but the directivity may be getting a little weird around that peak, which is not so easily equalized. There are a handful of 15" drivers which sound OK in the 1~2 kHz range - probably the Altec/GPA 416B (which will need EQ) and the Acoustic Elegance TD15M.
10~12" drivers are the obvious alternative, but then the efficiency is typically 2~3 dB lower. One way around that is using a pair of 10~12" drivers, which gets back to the desired efficiency target. The MTM layout works well for small drivers like the 5.5" drivers in the Ariel, but I have not been pleased with the sound of large MTM systems - however, that's a purely subjective opinion. You may like them just fine.
At one time, I was considering the layout used in the Altec monitoring loudspeaker, with twin 12" bass drivers side-by-side and below the horn. I think with the drivers directly next to each other (which they certainly won't be in a MTM system), the midbass will be fuller and more satisfying. For that matter, if I go ahead with twin 15" drivers, I most certainly will use a side-by-side layout with the free-space horn above.
A 1" exit compression driver is taking it really easy above 2 kHz - assuming the horn has competent diaphragm loading through the working range.
1.4 kHz - well, now we're needing to be more careful about the crossover, but still do-able if you're willing to mess around with the crossover and do a lot of subjective listening. (Are vocals harsh? Is the midrange congested-sounding on complex recordings? Raise the crossover and see if it goes away.)
1 kHz with 1" exit drivers is only for experts. I wouldn't even try it, and I've been doing crossovers for a while now.
Set aside the economics and look at the physics of the situation. Large-format compression drivers comfortably handle 500 Hz if the horn is large enough (at least 1.4X the size of the AH425, and preferably larger). That makes using 15" drivers very easy, with the efficiency advantages of 15" drivers and resulting increase in headroom in the bass range. If you're bold enough and have enough room, a pair of 15" drivers will truly satisfy - the audio equivalent of a V8 with twin turbos. All the power you could ever want.
Small-format drivers want to be crossed an octave or more higher. That's pretty much what you'd expect based on the differences in size of the diaphragm itself - it's like comparing a 15" bass driver to a 8" bass driver. The dynamic capabilities are very different.
With a crossover falling in the 1.4~2 kHz range, it's kind of the outer limit of what 15" drivers can do. Most 15" drivers have a broad peak around 1.5 kHz, which easily equalized, but the directivity may be getting a little weird around that peak, which is not so easily equalized. There are a handful of 15" drivers which sound OK in the 1~2 kHz range - probably the Altec/GPA 416B (which will need EQ) and the Acoustic Elegance TD15M.
10~12" drivers are the obvious alternative, but then the efficiency is typically 2~3 dB lower. One way around that is using a pair of 10~12" drivers, which gets back to the desired efficiency target. The MTM layout works well for small drivers like the 5.5" drivers in the Ariel, but I have not been pleased with the sound of large MTM systems - however, that's a purely subjective opinion. You may like them just fine.
At one time, I was considering the layout used in the Altec monitoring loudspeaker, with twin 12" bass drivers side-by-side and below the horn. I think with the drivers directly next to each other (which they certainly won't be in a MTM system), the midbass will be fuller and more satisfying. For that matter, if I go ahead with twin 15" drivers, I most certainly will use a side-by-side layout with the free-space horn above.
Last edited:
Bert Doppenberg's Klangfilm configuration has me fantasizing!
6moons industry features: X-Fi 2012 with Marja & Henk
6moons industry features: X-Fi 2012 with Marja & Henk