Hello,
The graphs were published in the French magazine called l'audiophile in 1986. I can put my speakers closer to the side walls behind the speakers is a BIG window. In front of the speakers there are 2 little walls starting at both side walls. If I put speakers closer to the side walls the speayers will be partly hidden by the 2 little walls when I sit in my listening position.
Maybe this could be a Problem?
I use the Tad2001 as well with a sand filled wooden horn also published in the French magazine.
Greetings, eduard
Ps in the future I am planning to use a pair of SVS active subwoofers that are now used in my homecinema set.
The graphs were published in the French magazine called l'audiophile in 1986. I can put my speakers closer to the side walls behind the speakers is a BIG window. In front of the speakers there are 2 little walls starting at both side walls. If I put speakers closer to the side walls the speayers will be partly hidden by the 2 little walls when I sit in my listening position.
Maybe this could be a Problem?
I use the Tad2001 as well with a sand filled wooden horn also published in the French magazine.
Greetings, eduard
Ps in the future I am planning to use a pair of SVS active subwoofers that are now used in my homecinema set.
Greets!
No doubt! Really need a scaled floorplan, but in general with rising on axis speakers such as expo horns it's a good plan to toe them in with the left channel pointing at the far right seating position and vice versa. if it's a very narrow 'sweet spot', then they should cross 'X' distance in front of it with 'X' determined empirically.
Will this ~ remove the side wall intrusions enough and/or cab they have some absorption added to the side facing the speakers?
Regardless, any toeing in beyond ~12 deg [included] will average out the various eigenmodes/'slap' echo between the cabs, room boundaries.
Note that if hard in the corners at an angle this ideally requires a large absorber to fill in the triangular gap behind the speakers. I just use rolls of R19 fiberglass attic insulation, though have no pets that can get back there, otherwise a massive cover needs to be used to seal it up.
Ditto behind wings/cab 'corners' unless angled > ~12 deg.
GM
No doubt! Really need a scaled floorplan, but in general with rising on axis speakers such as expo horns it's a good plan to toe them in with the left channel pointing at the far right seating position and vice versa. if it's a very narrow 'sweet spot', then they should cross 'X' distance in front of it with 'X' determined empirically.
Will this ~ remove the side wall intrusions enough and/or cab they have some absorption added to the side facing the speakers?
Regardless, any toeing in beyond ~12 deg [included] will average out the various eigenmodes/'slap' echo between the cabs, room boundaries.
Note that if hard in the corners at an angle this ideally requires a large absorber to fill in the triangular gap behind the speakers. I just use rolls of R19 fiberglass attic insulation, though have no pets that can get back there, otherwise a massive cover needs to be used to seal it up.
Ditto behind wings/cab 'corners' unless angled > ~12 deg.
GM
Yes, that was the set I built with Mr Hiraga and he lent them to me for a few weeks.
I may have helped with that measurement, can't remember. Ditto what GM says. A floor plan would help us see what your options are. And rotating them in so that they cross a bit on front of you does work well. I experimented with my recent A5 pair quite a bit, and corner placement with toe-in was the best. Because I had always used them in France straight ahead, the idea of corner placement and toe-in did not appeal to me at first. But in a smaller room it was surprising how well it worked.
Hi,
Thanks Eduard for the french paper. (I don't understand how they can curve such pannels for the horn ! Can you believe it: 5 layers of 5 mm ply for the horn!!!! Crazy & hard work ! Not for all enthusiasts for sure !
Some says also than lifting the cabinet with 10 to 20 cm leads helps a lot for bass renforsment with the VOTT ! Just take care with your back and feets...
Thanks Eduard for the french paper. (I don't understand how they can curve such pannels for the horn ! Can you believe it: 5 layers of 5 mm ply for the horn!!!! Crazy & hard work ! Not for all enthusiasts for sure !
Some says also than lifting the cabinet with 10 to 20 cm leads helps a lot for bass renforsment with the VOTT ! Just take care with your back and feets...
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I added bracing inside the horn flair and then filled with sand, 125 lb each.
I added bracing in the cabinets too.
Last post I had just started experimenting with post tuning, but I found them sounding more natural with the original size port. With the lower tuning it did not sound as real and lively.
I do have them corner loaded and use a big sub for the last little bit of low end.
I added bracing in the cabinets too.
Last post I had just started experimenting with post tuning, but I found them sounding more natural with the original size port. With the lower tuning it did not sound as real and lively.
I do have them corner loaded and use a big sub for the last little bit of low end.
I'll throw in with my Altec 515b horn, crossing to the sub at about 100hz. The top end is a peavey quadratic horn with TAD 2001. Sounds quite nice
Can you describe the cabinet of your 515b?
Much appreciated.
604-8G horn questions
Hi all! I figure this would be the place to get some opinions and have questions answered on my plans to have Great Plains Audio recondition my recently acquired 604-8G's. I picked up a pair of home made cabinets, the 620 I think, with late model drivers.
One woofer has been replaced with part number 23979-2 that Bill didn't recognize and the other appears to be original which is probably why they don't sound the same. Ironically, the original driver is the one I haven't been able to get to sound balanced. The woofer and horn just aren't blending well.
I've read criticisms of the faux multi-cell horn and I'm wondering if I should have GPA's newest horn design installed while the drivers are being reconditioned. How big a difference do you expect there would be, and would it adversely affect their resale value?
GPA's website says, "Our new exponentially-flared radial horn provides excellent upper end response not achieved in any previous version of the 604." The Altec 8G specifications claim they'll go 20kHz. The 8H-lll is also rated to 20kHz. So will the dispersion be much more even making the new horn noticeably better?
FYI my listening room is fairly narrow, only 11 feet wide, opening to the kitchen behind the listening position then to the living room. Speakers are out from the back wall about 2 feet and about 1.5 feet from the side walls/window. The listening position is about 8 feet from the speakers. I'm hoping my room is large enough to accommodate these guys because they sound so incredible on certain pieces, especially when bi-amped.
My next step is to build Jeff Markwart's crossover. Parts are on the way! I'm currently powering them with my FirstWatt J2.
Your thoughts are appreciated!
Hi all! I figure this would be the place to get some opinions and have questions answered on my plans to have Great Plains Audio recondition my recently acquired 604-8G's. I picked up a pair of home made cabinets, the 620 I think, with late model drivers.
One woofer has been replaced with part number 23979-2 that Bill didn't recognize and the other appears to be original which is probably why they don't sound the same. Ironically, the original driver is the one I haven't been able to get to sound balanced. The woofer and horn just aren't blending well.
I've read criticisms of the faux multi-cell horn and I'm wondering if I should have GPA's newest horn design installed while the drivers are being reconditioned. How big a difference do you expect there would be, and would it adversely affect their resale value?
GPA's website says, "Our new exponentially-flared radial horn provides excellent upper end response not achieved in any previous version of the 604." The Altec 8G specifications claim they'll go 20kHz. The 8H-lll is also rated to 20kHz. So will the dispersion be much more even making the new horn noticeably better?
FYI my listening room is fairly narrow, only 11 feet wide, opening to the kitchen behind the listening position then to the living room. Speakers are out from the back wall about 2 feet and about 1.5 feet from the side walls/window. The listening position is about 8 feet from the speakers. I'm hoping my room is large enough to accommodate these guys because they sound so incredible on certain pieces, especially when bi-amped.
My next step is to build Jeff Markwart's crossover. Parts are on the way! I'm currently powering them with my FirstWatt J2.
Your thoughts are appreciated!
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With the exception of the mega $$$ early true multicell duplex and GPA's discontinued AlNiCo 604 ES, I only recommend the 8H-lll for HIFI/HT, so if they were mine I'd swap to the larger horn. Frankly, I was hoping he would make it big enough for the original's 1 kHz XO that a 15" requires for best overall blend.
Bigger means it holds the pattern to a lower corner frequency plus it's missing the highly diffractive mouth grate, though ideally needs the Peavey foam treatment to further reduce these reflections back to the throat that are very visible in GPA's hi res response plot.
As for resale, obviously it will 'kill' it for traditionalists, but not for folks who understand/want the sonic improvement.
GM
Bigger means it holds the pattern to a lower corner frequency plus it's missing the highly diffractive mouth grate, though ideally needs the Peavey foam treatment to further reduce these reflections back to the throat that are very visible in GPA's hi res response plot.
As for resale, obviously it will 'kill' it for traditionalists, but not for folks who understand/want the sonic improvement.
GM
N801-8A Schematic
Does anyone have a schematic diagram for an Altec N801-8A crossover? I have found several homemade designs and modifications, but I would like to find a schematic of the original components. I have a pair of A7-8s that I bought in 1970 and I would like to freshen up the components, at least the capacitors. Thanks for your help.
Does anyone have a schematic diagram for an Altec N801-8A crossover? I have found several homemade designs and modifications, but I would like to find a schematic of the original components. I have a pair of A7-8s that I bought in 1970 and I would like to freshen up the components, at least the capacitors. Thanks for your help.
N501 and N801-8A are simple 'textbook' 2nd order Butterworth XOs, so for N801 use 17.5 MFD caps and 2.25 uF inductors: http://classicaudio.ru/forum/uploads/monthly_05_2011/post-622-1385471289,743.jpg
GM
GM
Altec 846B Valencia
I been playing with a pair of these. I wanted to refrain from too much mutulation and keep them as the designers intended, only bring components up to date.
All I have changed is the crossover caps, Solen for the low pass and I had a couple of Hovland’s around for the high pass that were leftovers from a JBL project some years back.
Next, I changed out the compression drovers to the GPA 902’s.
Very impressive performance now. No more banana curve FR.
For reference my main system is JBL four way 4345 with TAD 2002 HF Be HF drivers and modernized crossover capacitors.
I been playing with a pair of these. I wanted to refrain from too much mutulation and keep them as the designers intended, only bring components up to date.
All I have changed is the crossover caps, Solen for the low pass and I had a couple of Hovland’s around for the high pass that were leftovers from a JBL project some years back.
Next, I changed out the compression drovers to the GPA 902’s.
Very impressive performance now. No more banana curve FR.
For reference my main system is JBL four way 4345 with TAD 2002 HF Be HF drivers and modernized crossover capacitors.
Homemade Valencia Wannabe Cabinets
Finally finished up my Altec-Lansing Valencia wannabe cabinets. I made them from some nice red oak 3/4” plywood that I found at Home Depot. It seemed to be good quality with very little voids in the layers. Did the cuts with a circular saw using a Kreg Accu-Cut guide, which worked out really well. Nice straight edges and good square joints. I screwed & glued cleats throughout and just butt jointed the panels. I came back and sealed all of the seams with GE Iron Grip Silicone and then put 2 x 3 stiffeners on the back panels. The result is a really tight cabinet. I had some 4” PVC pipe leftover from another project that worked out perfectly for the ports. I painted them with a good high gloss enamel which turned out pretty well and then stretched some acoustically transparent material across 3/4 x 3/4 frames that fit into the setback.
I pulled the components out of my big A7 cabinets that I bought new in 1971. Everything was in great shape, but I went ahead and changed out the capacitors in the crossovers to a new set of Solen’s.
I drew up the plans for the boxes based on the Valencia specs in the Altec enclosure guide, but not exactly to the micron. I sized them so that the front of both drivers were in alignment without having to cut that hole in the back panel to accommodate the HF driver. I just guessed at cutting the port tubes at 6” in length. Without any further tuning or tweaking they sound great! Overall, I am pleased with the performance since I was worried they would lose a lot of bass without that big folded horn. These cabinets deliver plenty of rich bass and actually seems a bit tighter than in the A7 boxes. There is definitely loss of energy in the very low registers, but I have plans for subwoofer project that should fix that. The only objection I have at the moment is there seems to be a spike in the upper mid range that can be a little annoying on some music. This is not a cabinet issue since it’s all from the HF section of the system, so I will have see if I can work on that next. Any suggestions are welcomed.
Anyone need a set of A7 cabinets? Cheap. The cost of pallets and motor freight will be the biggest cost.
Finally finished up my Altec-Lansing Valencia wannabe cabinets. I made them from some nice red oak 3/4” plywood that I found at Home Depot. It seemed to be good quality with very little voids in the layers. Did the cuts with a circular saw using a Kreg Accu-Cut guide, which worked out really well. Nice straight edges and good square joints. I screwed & glued cleats throughout and just butt jointed the panels. I came back and sealed all of the seams with GE Iron Grip Silicone and then put 2 x 3 stiffeners on the back panels. The result is a really tight cabinet. I had some 4” PVC pipe leftover from another project that worked out perfectly for the ports. I painted them with a good high gloss enamel which turned out pretty well and then stretched some acoustically transparent material across 3/4 x 3/4 frames that fit into the setback.
I pulled the components out of my big A7 cabinets that I bought new in 1971. Everything was in great shape, but I went ahead and changed out the capacitors in the crossovers to a new set of Solen’s.
I drew up the plans for the boxes based on the Valencia specs in the Altec enclosure guide, but not exactly to the micron. I sized them so that the front of both drivers were in alignment without having to cut that hole in the back panel to accommodate the HF driver. I just guessed at cutting the port tubes at 6” in length. Without any further tuning or tweaking they sound great! Overall, I am pleased with the performance since I was worried they would lose a lot of bass without that big folded horn. These cabinets deliver plenty of rich bass and actually seems a bit tighter than in the A7 boxes. There is definitely loss of energy in the very low registers, but I have plans for subwoofer project that should fix that. The only objection I have at the moment is there seems to be a spike in the upper mid range that can be a little annoying on some music. This is not a cabinet issue since it’s all from the HF section of the system, so I will have see if I can work on that next. Any suggestions are welcomed.
Anyone need a set of A7 cabinets? Cheap. The cost of pallets and motor freight will be the biggest cost.
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I miss my Altecs...
I check this thread periodically, just to smile and drool.
Back in the early 1990s sometime, I acquired most of the original IPC/Simplex/Altec sound system originally installed in the Bytowne Theatre in Ottawa, ON around 1950. 2 IPC amp racks, 5 Altec A5s, and a a pair of 604-8Gs in factory Altec oak cabinets. (There were more 604-8Gs, but I only got 2.) They wanted THX certification
I sold the 604-8Gs to a friend who loved them, for the cost of reconing one of them. Duh. When you've got too much "stuff"... and WAF...
The A5s were loaded with original 515 (no letter suffix) 16 ohm woofers (the ones with the felt and phenolic-harp bolt-down spider), and had 805 multicells with 24 ohm 288B drivers. One had been factory-upgraded to a 16 ohm 288C. Two of them needed the 515s re-coned. These things sat behind a movie screen for 40+ years before I acquired them, so the black 825 cabs, and the original woofer cones, and the horns were all splattered with silver screen paint.
I picked 2 of the best original A5s for my basement "family room/man cave"-- a 16' x 26' x 9' slightly irregular room. Tweaked crossovers closely based on the Hiraga A5 crossover published in Sound Practices way back, by Jon Stronczer as I recall...added a pair of JBL 2404h tweeters above 10k... added a pair of sealed EVM15 woofers below 70Hz with a Linkwitz transform flat down to 20... drove the subs with a home-brew SS amp, drove the mains with a pair of the IPC AM1027 6L6 tube amps.
and we had... "The Arm".
"Don't go down there and start listening to music, you'd better be serious, The Arm'll get ya... resistance is futile". More times than I care to recall, an "early evening" of listening to some Steely Dan and Pink Floyd morphed into greeting the sunrise with Berlin Philharmonic Strauss Waltzes or the Telarc 1812 Overture...
We could do real live-concert levels in that room, and when I put a scope on the AM1027 outputs and monitored power levels to the A5s, we might have hit occasional peaks of 4 watts per channel
Long story shortened...10 years ago I sold that house, moved to a place with smaller rooms, and the A5s got bartered away. I still have the IPC racks and amps- 6 AM1027s, 1 AM1026 (plus all the iron to build a twin for it), and an AM1029 SE projection booth monitor amp.
I'll never forget the sound of those Altecs. I'll soon have a new listening room, smaller (12' x 20') with WAF in full play, figuring out how to best apply a pair of JBL 2204, a pair of 2426, and a pair of Hartley 18" woofers (those get IB'd from the attic )
I've followed just about everything Earl Geddes, Wayne Parham, and Evan (Zilch) Flavell have opined on over the past decade or so... I guess I'm moving into 3-PI territory. but I'm still jonesing for Altec multicells.
Here's a couple pics from the old place- sorry my old Nikon 5100 refused to auto-focus properly in that room- I almost believe the Altec multicells screwed with the ultrasonic AF... That's my son standing between the speakers in the middle pic
Cheers, Altec afficionados!
I check this thread periodically, just to smile and drool.
Back in the early 1990s sometime, I acquired most of the original IPC/Simplex/Altec sound system originally installed in the Bytowne Theatre in Ottawa, ON around 1950. 2 IPC amp racks, 5 Altec A5s, and a a pair of 604-8Gs in factory Altec oak cabinets. (There were more 604-8Gs, but I only got 2.) They wanted THX certification
I sold the 604-8Gs to a friend who loved them, for the cost of reconing one of them. Duh. When you've got too much "stuff"... and WAF...
The A5s were loaded with original 515 (no letter suffix) 16 ohm woofers (the ones with the felt and phenolic-harp bolt-down spider), and had 805 multicells with 24 ohm 288B drivers. One had been factory-upgraded to a 16 ohm 288C. Two of them needed the 515s re-coned. These things sat behind a movie screen for 40+ years before I acquired them, so the black 825 cabs, and the original woofer cones, and the horns were all splattered with silver screen paint.
I picked 2 of the best original A5s for my basement "family room/man cave"-- a 16' x 26' x 9' slightly irregular room. Tweaked crossovers closely based on the Hiraga A5 crossover published in Sound Practices way back, by Jon Stronczer as I recall...added a pair of JBL 2404h tweeters above 10k... added a pair of sealed EVM15 woofers below 70Hz with a Linkwitz transform flat down to 20... drove the subs with a home-brew SS amp, drove the mains with a pair of the IPC AM1027 6L6 tube amps.
and we had... "The Arm".
"Don't go down there and start listening to music, you'd better be serious, The Arm'll get ya... resistance is futile". More times than I care to recall, an "early evening" of listening to some Steely Dan and Pink Floyd morphed into greeting the sunrise with Berlin Philharmonic Strauss Waltzes or the Telarc 1812 Overture...
We could do real live-concert levels in that room, and when I put a scope on the AM1027 outputs and monitored power levels to the A5s, we might have hit occasional peaks of 4 watts per channel
Long story shortened...10 years ago I sold that house, moved to a place with smaller rooms, and the A5s got bartered away. I still have the IPC racks and amps- 6 AM1027s, 1 AM1026 (plus all the iron to build a twin for it), and an AM1029 SE projection booth monitor amp.
I'll never forget the sound of those Altecs. I'll soon have a new listening room, smaller (12' x 20') with WAF in full play, figuring out how to best apply a pair of JBL 2204, a pair of 2426, and a pair of Hartley 18" woofers (those get IB'd from the attic
) I've followed just about everything Earl Geddes, Wayne Parham, and Evan (Zilch) Flavell have opined on over the past decade or so... I guess I'm moving into 3-PI territory. but I'm still jonesing for Altec multicells.
Here's a couple pics from the old place- sorry my old Nikon 5100 refused to auto-focus properly in that room- I almost believe the Altec multicells screwed with the ultrasonic AF... That's my son standing between the speakers in the middle pic
Cheers, Altec afficionados!
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I think I've posted this somewhere other than the altec thread. This is my home made k horn = a pair. (actually electro voice georgean from their plans) speakers are altec vott== 15" bass and 511 horn. Outer cabinet is walnut plywood
Due to the many compound cuts, and many pieces, I would not recommend actually building these- unless you have a lot of time to spend= and lots of room in your house. I drive these with a home brew amp each channel p=p 6l6. Just barely crack the gain control!
Due to the many compound cuts, and many pieces, I would not recommend actually building these- unless you have a lot of time to spend= and lots of room in your house. I drive these with a home brew amp each channel p=p 6l6. Just barely crack the gain control!
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