Avalanche AS1 was an active 3-way speaker made in early '90s in Finland by a small company in Eastern Finland.
It is an active 3-way speaker with analog line level xo and three amplifier boards with Hitachi K135 MOSFET amplifiers.The box is made of soupstone, dead weight 86kg a piece! Drivers are ScanSpeak 21W/8555 (pair) Audax/Polydax 4" mids (pair) and a Dynaudio D28 tweeter.
This pair was for sale at a Finnish hifi-forum, and to my surprise I knew the owner! He had bought this pair just before the bankcrupcy of the company. The speakers had one bass drivers changed but still they suffered from poor sound.
I just had to push the buy button, but for totally altruistic reasons - I will give this pair to my younger son!
It is an active 3-way speaker with analog line level xo and three amplifier boards with Hitachi K135 MOSFET amplifiers.The box is made of soupstone, dead weight 86kg a piece! Drivers are ScanSpeak 21W/8555 (pair) Audax/Polydax 4" mids (pair) and a Dynaudio D28 tweeter.
This pair was for sale at a Finnish hifi-forum, and to my surprise I knew the owner! He had bought this pair just before the bankcrupcy of the company. The speakers had one bass drivers changed but still they suffered from poor sound.
I just had to push the buy button, but for totally altruistic reasons - I will give this pair to my younger son!
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Measurements of the purchased problematic pair, #107 and #108
Nearfield, with all drivers playing (attachments)
Farfield done by other person, distance and IRgating unknown
Nearfield, with all drivers playing (attachments)
Farfield done by other person, distance and IRgating unknown
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My friend Hanski has given me invaluable help and support with this project! We drove 600km to pick up the speakers and dropped them at his summer cabin by lake Leppävesi here in Jyväskylä. https://kartta.jkl.fi/IMS/?layers=Opaskartta&cp=6906064,497568&z=16&title=Jkl
Hanski's cabin has lush and intimately lit dedicated listening room and a generous workspace for various projects! Thank you for sharing! We measured the speakers and then dismantled #107 first. My idea was to make them minidsp'd and to change the mid/tweeter system.
I had Audax HM100Z0 midranges waiting for a project. I bought second hand pair of ScanSpeak (Vifa) D2608 tweeters and a new pair of SS 21W/8555 woofers. Hanski soldered the line-out wires from minidsp 2x4HD directly to main amplifier boards. A jump wire was connected to original xo-board to get signal to start-relays of amplifiers. We added an outboard AC socket for minidsp. I made some plywood plates to adapt new drivers and to block the opening of the original tweeter. A new baseplate was made too - the bow will be sealed instead of original bass-reflex.
Some pictures from the workshop.
Hanski's cabin has lush and intimately lit dedicated listening room and a generous workspace for various projects! Thank you for sharing! We measured the speakers and then dismantled #107 first. My idea was to make them minidsp'd and to change the mid/tweeter system.
I had Audax HM100Z0 midranges waiting for a project. I bought second hand pair of ScanSpeak (Vifa) D2608 tweeters and a new pair of SS 21W/8555 woofers. Hanski soldered the line-out wires from minidsp 2x4HD directly to main amplifier boards. A jump wire was connected to original xo-board to get signal to start-relays of amplifiers. We added an outboard AC socket for minidsp. I made some plywood plates to adapt new drivers and to block the opening of the original tweeter. A new baseplate was made too - the bow will be sealed instead of original bass-reflex.
Some pictures from the workshop.
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I have had an idea of making a low-directivity classic 3-way boxed speaker for many years. My first two hifi-speakers were 3-ways and I liked them a lot. I love the impulsive bass from a closed box 3-way speaker! And I love the sound of a well-balanced 3-way with minimal directivity!
Here are simulations of my selected drivers in the baffle, as per The Edge, my favourite little simulator!
And my in-room gated measurements of chosen drivers in the box (smoothed), without eq.
Here are simulations of my selected drivers in the baffle, as per The Edge, my favourite little simulator!
And my in-room gated measurements of chosen drivers in the box (smoothed), without eq.
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My first poorly educated quess for xo is LR2 at 400/4000Hz. The mid and tweeter have some physical time-alignment to help integration, here no delay adjustment! Measured at listening/tweeter axis at 140cm distance, in-room. The far-field response of each driver was eq'd before setting xos. I had no time to do off-axis measurements today.
There were some bad soldering and wrong polarities first, but problems were solved after some brainwork! Here measurements with xo. The graph with individual driver responses has wrong summed response. The midrange was soldered in wrong polarity first... Each pair had a broken woofer, but fortunately these are still available! Woofers are connected parallelly. Original midranges were in series, upper ones with parallel 10uF caps!
Me happy! Just copy the procedure (without mistakes) to #108 next week! Installation plates must be redone to make drivers fit the cabinet better. The wiggles at 5-6 kHz come from the poor fitting of the tweeter to the waveguide.
I have a faint idea of making a back-lighted plastic screen with a logo in the place of the original tweeter...
There were some bad soldering and wrong polarities first, but problems were solved after some brainwork! Here measurements with xo. The graph with individual driver responses has wrong summed response. The midrange was soldered in wrong polarity first... Each pair had a broken woofer, but fortunately these are still available! Woofers are connected parallelly. Original midranges were in series, upper ones with parallel 10uF caps!
Me happy! Just copy the procedure (without mistakes) to #108 next week! Installation plates must be redone to make drivers fit the cabinet better. The wiggles at 5-6 kHz come from the poor fitting of the tweeter to the waveguide.
I have a faint idea of making a back-lighted plastic screen with a logo in the place of the original tweeter...
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Yesterday we assembled the other speaker sno108.
The amplifier was a little different. It happened that we lost some of the smoke that runs the woofer amplifier. Reason for this was loosened wire of the relay that switches the amp on. Obviously the amp started oscillating and some resistors heated... The funny thing was that we didn't notice this difference until the re-assembled speaker gave no sound from bass drivers.
Well, it was an easy fix with extensions and we had a change to listen to the pair for a while! They sounded nice, but obviously low bass needs some eq. in a rather large room. Mic was not available.
We will organize an intimate listening session for our friends at May 7th. New adapters/waveguides will be fitted for tweeters then too, and some more eq'ing and xo tuning based on listening impressions!
The amplifier was a little different. It happened that we lost some of the smoke that runs the woofer amplifier. Reason for this was loosened wire of the relay that switches the amp on. Obviously the amp started oscillating and some resistors heated... The funny thing was that we didn't notice this difference until the re-assembled speaker gave no sound from bass drivers.
Well, it was an easy fix with extensions and we had a change to listen to the pair for a while! They sounded nice, but obviously low bass needs some eq. in a rather large room. Mic was not available.
We will organize an intimate listening session for our friends at May 7th. New adapters/waveguides will be fitted for tweeters then too, and some more eq'ing and xo tuning based on listening impressions!
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Renovated Avalanche speakers listened to and compared to a pair of SF Olympica II and PA speakers. I put +5dB shelf to low bass and sound was very much like SF. Differences in low and middle bass were most obvious. Unfortunately I forgot to take my UMIK along, so no measurements this time!
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This Tidal Audio's entry level speaker looks to have the smoothest wide dispersion that I have seen measured, this time to 45¤ hor. Obviously it needs some space around to sound good, but room measuremet is not too bad. I might have set MT xo even higher than 2.2kHz. Slopes are LR2.
Tidal Audio Akira loudspeaker Measurements | Stereophile.com
My Avalanche project is on hold.
Tidal Audio Akira loudspeaker Measurements | Stereophile.com
My Avalanche project is on hold.
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I abandoned that ellipse shape. More like Sonus Faber, plates from double 6mm plywood. I must only find a way to attach it airtightly, preferably without glueing...
New photos at the end of album Avalanche AS1 - Google Photos
Wintersports, -20C
New photos at the end of album Avalanche AS1 - Google Photos
Wintersports, -20C
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Those mounting holes narrow down some driver possibilities.
Really going with some plywood on stone?
Stock AS1 looks cool
Really going with some plywood on stone?
Stock AS1 looks cool
Original mounting cutouts and screw holes are limiting my choices too much. I just have to find a way to make this panel ti fit tightly. It looks quite good with black leather cover, IRL!
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Winter is almost overcome now, so I must show my progress... I sacrificed my 10 years ole Turkish leather jacket for the masks! I plan to glue them on place soon. Unfortunately I destroyed the other tweeter douring test assembly, so I must order a replacement, when I get funding raised.
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I broke the other SS tweeter's connecting lids when test mounting it in May.
I received three of these instead today!
www.audioexcite.com >> SB Acoustics SB26STAC-C000-4
I received three of these instead today!
www.audioexcite.com >> SB Acoustics SB26STAC-C000-4
Baby, it's cold out there - time to go on... so I brought the babies back home from the storage!
SB Acoustic SB26STAC have almost same flange as SS 26, so they dropped in nicely. I changed serial (protective) caps to 6.8uF AudynCap Plus and took some handheld measurements to set minidsp parameters. Baffle gives axial 5kHz dip in tweeter response, that needs also off-axis measurements to be eq'd. The other speaker's amps have 6db less gain, so I boosted it in minidsp. Sealed bass needs some kind of shelf ala LT too, below 50Hz. Crossovers are now LR2 at 400/4000Hz.
Speakers sound very nice and very closed-box type in both good and bad compared to AINOs. They are now in corners of our bedroom, but most likely will end up at our summer cabin later in the spring when I can drive there on ice! First I'll ty to find time to do proper indoor measurements on a turntable...
Avalanche AS1 modernization - Google Photos
SB Acoustic SB26STAC have almost same flange as SS 26, so they dropped in nicely. I changed serial (protective) caps to 6.8uF AudynCap Plus and took some handheld measurements to set minidsp parameters. Baffle gives axial 5kHz dip in tweeter response, that needs also off-axis measurements to be eq'd. The other speaker's amps have 6db less gain, so I boosted it in minidsp. Sealed bass needs some kind of shelf ala LT too, below 50Hz. Crossovers are now LR2 at 400/4000Hz.
Speakers sound very nice and very closed-box type in both good and bad compared to AINOs. They are now in corners of our bedroom, but most likely will end up at our summer cabin later in the spring when I can drive there on ice! First I'll ty to find time to do proper indoor measurements on a turntable...
Avalanche AS1 modernization - Google Photos
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Some indoor measurements after eq, LR2 xo set in dsp at 400 and 4000Hz. Wiggles around 1,2kHz are reflections in the room.
Other speaker's amp has 6dB more gain compared to the other and it's input trigger function doesn't seem to work. Last night I heard it ticking about once a minute and in the morning box surface temp at amplifer module was 45C, the other amp was just 25C. The amp most likely has overheating realay which was ticking and now it stayed silent after the very first sweep. I'll have to let it cool down and then remove the amp module and check connections. I can't measure or analyze electronics, I need help for that! My speakers were sold out of factory when the manufacturer went down, no wonder...
More measurements in Google album Avalanche AS1 modernization - Google Photos
Other speaker's amp has 6dB more gain compared to the other and it's input trigger function doesn't seem to work. Last night I heard it ticking about once a minute and in the morning box surface temp at amplifer module was 45C, the other amp was just 25C. The amp most likely has overheating realay which was ticking and now it stayed silent after the very first sweep. I'll have to let it cool down and then remove the amp module and check connections. I can't measure or analyze electronics, I need help for that! My speakers were sold out of factory when the manufacturer went down, no wonder...
More measurements in Google album Avalanche AS1 modernization - Google Photos
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OK, both speakers working again... Room mesaurements! I eliminated Linkwitz Transform eq because speakers ae in the corner now, and adjusted tweeter's eq a bit.
Sealed woofers are just so fine! 10-20kHz response with almost ideal Harman curve. 100-300Hz a bit recessed obviously because of floor, ceiling and wall cancellations.
RT of the room is fine, walls are gypsum board and ceiling is lowered wood panel. Sized 3x6m, speakers at the corners of narrow end.
Sealed woofers are just so fine! 10-20kHz response with almost ideal Harman curve. 100-300Hz a bit recessed obviously because of floor, ceiling and wall cancellations.
RT of the room is fine, walls are gypsum board and ceiling is lowered wood panel. Sized 3x6m, speakers at the corners of narrow end.
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I raise my hands - the other speaker's amp gets over my head. I took it off and tried to see the cause of high gain and overheating. Only thing I could do was to set variable gain potentiometer to lower gain. But after putting it back it blew a fuse! There was a stamp with date 12nd March 1991.
I just ordered two Hypex FA123 plate amp-dsp boards. I must place them externally and extend speaker wires, but that is relatively easy. Biggest problem is that I couldn't now find an aluminium box big enough (length 360mm)
I used FA123s in another project 3 years ago so this was an easy decision, but I hoped to not go for it. Some have had problems with them, but mine have worked as fine as steam train's toilet!
I just ordered two Hypex FA123 plate amp-dsp boards. I must place them externally and extend speaker wires, but that is relatively easy. Biggest problem is that I couldn't now find an aluminium box big enough (length 360mm)
I used FA123s in another project 3 years ago so this was an easy decision, but I hoped to not go for it. Some have had problems with them, but mine have worked as fine as steam train's toilet!
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