The ability of moving lots of air below 800 cycles or so is where it gets difficult and most systems miss the important bottom octave (this is really the foundation of "feel" begins)and ultra important 80 to 300 Hz range where direct radiators don't interface with the rooms airload efficiently like a horn and normally have major dips in the response due to floor, ceiling and sidewall interference. A well placed front midbass horn in my experience (even with a 8"driver) can pull this off better then a 7 foot array of four good pro sound 15's. The difference is not subtle when it comes to the body saying "is this live?" it's really worth the time to build a horn to try this for yourself. Just build one and listen in mono first to save timeA good horn system will scare the crap out you (meaning you actually will be fooled into believing the sound is real- as in being startled or shocked) and you'll like it. This is why you see hornys building these big systems, they work!
Is there a a bass (and midrange) horn that would work with the Le Cleac'h horn being discussed in this thread (crosses below 700 hz)?
Using a true bass horn for impact and moving air is fine and all. But in my opinion what is more important for me is to have a HF horn that doesn't have any horn colorations, which I believe is what Lynn likes about the Le Cleac'h as well.
This is my view confirmed by practical experience. It is also common sense
I have asked Jean Michelle if he can confirm sources in Europe that sell a genuine JMLC because I am looking at maybe a smaller flare than the excellent existing option with 1 1/4". But Bill Geddes has whetted my appetite for an OS. Pity all the ALTEC and older JBL units are non existent in the UK. Its hard to get items in from the US.
I will not bother with a bass horn as there are many good alternatives. I am trying to avoid a super tweeter so I will probably go for 1" for my first attempt. If there was enough demand for a group buy that would be a thought too. We all have different circumstances and variations on a theme are not an issue and may even find a better revision.
How about a Polish horn for you? jzagaja is a member here I believe...
http://www.autotech.pl/pdf/audio_en.pdf
You could ask if he makes something to your liking...
And do you mean Earl?
http://www.autotech.pl/pdf/audio_en.pdf
You could ask if he makes something to your liking...
And do you mean Earl?
Through the years I have frequently read a couple of pages in this thread, but I still don't know what kind of speaker the 'Beyond the Ariel' is. Lynn, would you give me a short summary please
Frequency response flatness and decay-from-impulse is equal or better than the Ariel, with 5 to 8 dB greater efficiency, and 10 dB or better headroom. Overall system balance is similar to the Ariel, if possible.
The first working prototypes use the AH425 Azurahorn, Radian 745Neo with either aluminum or beryllium diaphragms (16 ohm), and GPA (modern Altec) 416 with Alnico magnets and 16-ohm voice coil. Resistive-vented bass cabinet of about 5 cubic feet. Passive crossover is electrically 4th-order LP, transitional between LR4 and Bessel, at 700 Hz. Woofer highpass has Zobel inductance correction and is 3rd-order LP. MF/HF system is autoformer attenuated with 16-ohm swamping resistor (in parallel with primary) in the input side.
Much of the recent discussion, aside from a digression into metaphysics, is the most appropriate bass channel to match the MF/HF section. Gary Dahl is building his own version and has posted measurements of two version of the Radian 745 (ceramic+aluminum, neodymium+beryllium) using the AH425 horn.
Last edited:
of course you can build a horn to cover that range. Hypex expansion is probably the best for small size and performance. the upper range horn is important but the fundamentals in the 100 to 800 Hz range is where you get the most benefit by horn loading. If i were to forced to go back to a box and a cone i know I'd drag out the electrostats and live with the fake compression first. You must consider floor type, room placement and how much ripple you can live then build it and enjoy. as far as the Le Cleach not having any coloration forget about it. It will beam badly and will have lobing issues with the treble horn because it's size is not practical unless you take it all the way up, forgo a real tweeter and sit in a small sweet spot. That may be what you want but there are other horns that are far more livable and sound fantastic.
Common sense tells me a 6 inch woofer won't move enough air with low distortion and low compression to sound real with music... What's the smallest bass instrument? Unless of course if the 6" (a good horn driver) is loaded in a proper horn. We all have different expectations of what is possible as result of doing it right. I think that's why people disregard what really happens with a direct radiator and the air in the room. i alsothink it has something to do with the garbage the high end magazines and manufactures put out selling their 10 thousand dollar toys.
The first prototypes are at a friend's house in another city, about 800 miles from here. The measurements were made with unfamiliar test gear I wasn't sure about, but they gave an overall impression of impulse response and frequency response. The flatness goal is met, and impulse decay is less than 0.5 mSec, both comparable to the Ariel, and maybe a little better.
The subjective balance is very close to the Ariel, with greater dynamic capability. Imaging is a little different, somewhat deeper (subjective depth 50 feet), and also coming further into the room (to the listener's knees on some recordings). The slot vent, which is located on the sides of the prototype cabinets, will be re-located to the floor when I build my cabinets.
Next step: my cabinets. I am leaning towards a dual-woofer configuration, using a pair of GPA 416 Alnico's. Not decided on the merits of a vertical or horizontal array of drivers; the floor image has to be part of the overall response and polar characteristic. There's a possibility of a short bass horn cutting off at 200 Hz combined with a direct-radiator woofer below that (with active crossover and separate amplification).
The rough measurements made of the first prototypes indicated the Qts of the 416 is much lower (perhaps as low as 0.21) than the official GPA specs, and efficiency is higher, in the 98 to 99 dB/meter range. There is a set of measurements here that show a lot of variation for the Altec 416 over the years, when you look at Qts, moving mass, and efficiency. GPA is currently specifying the moving mass of both the 416 and 515 as 71 grams, which is similar to the majority of the drivers measured here. I am looking forward to what Gary Dahl measures on his pair of new-production 416 Alnico's.
Quick description of Gary Dahl's system: Gary was my neighbor back when I was living in Washington State, and we've shared in various projects over the years. He's had his version of the high-efficiency speakers on pause for a couple of years, and has re-started his project. It's similar to what I'm doing, with AH425 horns, Radian 745 compression drivers, a 700 Hz passive crossover, but with Acoustic Elegance TD-15M bass drivers, and a TD-series subwoofer directly below the TD-15M's.
He's very satisfied with the sound he's getting now, based on what he's told me on the phone, and he's curious how the GPA 416 Alnico's will compare to the TD-15M's, both by measurement and subjectively.
Last edited:
Pooh,
I know it goes against what you believe but I can assure you that I am producing bass that others who are recording engineers and designers have been more than surprised. First of all I have developed my own cone material, not something off the shelf that has very low distortion properties. The other thing is that the magnetic system is very unusual to say the least. It is a solenoid designed magnet system with a magnetic gap length of 1.25" in length using large quantities of high 52 MgOe neodymium. The voicecoil is only about 0.3" long and never sees a change in the gap energy during the entire travel of the cone. This is an ultra-linear motor design. Some may complain that this must cause a Doppler shift in the higher frequencies but nobody has detected this in real usage. So we have an extreme excursion that will easily attain any normal Spl level that most people would consider practical. The impedance rise with no conjugate network correction, as measured directly from the driver has a minimum resistance of approx. 3.75ohms and tops out at approx 13.7ohms at about 20khz with no perturbations. The benign phase angle is also very unusual for such a small speaker covering the range that it does. Of course there is a peak at resonance but that is normal. I will need to reinstall my scanner software and I will publish the specification for you all to see. This testing was done independently so you can comment after I publish the information. I will very soon be offering this version of the speaker to the diy community for those who don't have the room or the inclination to build a large speaker system.
I know it goes against what you believe but I can assure you that I am producing bass that others who are recording engineers and designers have been more than surprised. First of all I have developed my own cone material, not something off the shelf that has very low distortion properties. The other thing is that the magnetic system is very unusual to say the least. It is a solenoid designed magnet system with a magnetic gap length of 1.25" in length using large quantities of high 52 MgOe neodymium. The voicecoil is only about 0.3" long and never sees a change in the gap energy during the entire travel of the cone. This is an ultra-linear motor design. Some may complain that this must cause a Doppler shift in the higher frequencies but nobody has detected this in real usage. So we have an extreme excursion that will easily attain any normal Spl level that most people would consider practical. The impedance rise with no conjugate network correction, as measured directly from the driver has a minimum resistance of approx. 3.75ohms and tops out at approx 13.7ohms at about 20khz with no perturbations. The benign phase angle is also very unusual for such a small speaker covering the range that it does. Of course there is a peak at resonance but that is normal. I will need to reinstall my scanner software and I will publish the specification for you all to see. This testing was done independently so you can comment after I publish the information. I will very soon be offering this version of the speaker to the diy community for those who don't have the room or the inclination to build a large speaker system.
Any preview pics of this very interesting driver? I'd love to see how you did the suspension and spider. Isn't that the most difficult part of the design, with that small a diameter and that high an excursion the suspension is becoming a much bigger fraction of the whole radiating surface compared to a bigger but lesser excursion driver having the same volume displacement?
KSTR,
I will put up a picture soon of the driver. You are correct that getting the suspension correct is a major part of the design of a long excursion driver. The spider itself wasn't much problem, the surround was the limitation. Without going to a very wide frame so you can have a very wide surround there are not many ways to achieve this kind of excursion. I will not use a very wide, surround as you pointed out then it becomes a real problem with phase problems between the cone and surround. A standard M-roll also will have a limited travel. The trick is to keep the surround at a reasonable width while allowing a long linear excursion.
I will put up a picture soon of the driver. You are correct that getting the suspension correct is a major part of the design of a long excursion driver. The spider itself wasn't much problem, the surround was the limitation. Without going to a very wide frame so you can have a very wide surround there are not many ways to achieve this kind of excursion. I will not use a very wide, surround as you pointed out then it becomes a real problem with phase problems between the cone and surround. A standard M-roll also will have a limited travel. The trick is to keep the surround at a reasonable width while allowing a long linear excursion.
Hi Lynn,
Thank you for the info.
Having no speakers' DIY experience and almost zero knowledge of the speakers-related technical terms you and others are using here, I have no idea what the technical data you mentioned means.
Since I have a very strong sense that I'd like what you like (sound-wise), I'm waiting for the 'beyond Ariel' progress and completion.
I'm sorry I cannot assist this project in any practical way.
Thank you for the info.
Having no speakers' DIY experience and almost zero knowledge of the speakers-related technical terms you and others are using here, I have no idea what the technical data you mentioned means.
Since I have a very strong sense that I'd like what you like (sound-wise), I'm waiting for the 'beyond Ariel' progress and completion.
I'm sorry I cannot assist this project in any practical way.
Hi Lynn
Could I add a vote for a possible vertical orientation (or both)? I have this crazy idea in my head to double the width of the cabinet and add a pair of 15" motional-feedback woofers on the side. The XO can be from 90Hz on down. Not having to reproduce any low bass should also reduce distortion of the drivers in the midrange. I know this sounds crazy, but these are my dream speakers, and when I have the space to house them, a double-width cabinet will not be an issue.
The other question I have is regarding the GPA 416 Alnico drivers. Are you still considering using the GPA 515 drivers?
Then one last question regarding the use of dual mid-bass drivers- will you still use the 16-ohm Radian 745Neo? If you use two mid-bass drivers in parallel, would that not be changed for the 8-ohm version?
Thanks,
Deon (the crazy nut from South-Africa)
How about a Polish horn for you? jzagaja is a member here I believe...
http://www.autotech.pl/pdf/audio_en.pdf
You could ask if he makes something to your liking...
And do you mean Earl?
Thanks for that. I will look at it. I hope it would get JMLC approval. If he wants people to use his profile then he should promote it. I am humbled by my years in aero technology, but where we have differing experience views or agendas we must work together. We are a niche of a niche and that ' Aint a bad thing' Only the best horn is going to beat the direct drivers. I think Geddes approach is very appealing, and flying the flag for horns.
Last edited:
What sort of amplification were you thinking of for the direct radiator woofer? And have you heard the prototypes with your Karna amps or something else?
Thanks Gary. I've often read that the chest cavity resonant frequency is about 90Hz. Not sure how true that is. When I used to mix live Rock, 100Hz was the boost area we always started with on the kick drum to get the thump. Depending on the drum and the speakers, that might move up or down a little, but 100 Hz was always the starting point. That's where the "Kick" is, the chest pound.