Matching up Advents for Stacking

[Guest mrspike]

When stacking Advents do the four speakers need to be the same vintage? I am in the process of refurbishing my 1976 era Large Advents with the Masonite woofer. If I want to add a pair do they need the Masonite woofer as well, or will the steel frame ones match up? What about crossovers from different units, will they need to be matched? Thanks in advance for your input.

[MartyK]

While other may disagree, I have stacked OLA's on NLA's. The result is quite in impressive. So, although most people probably stack like models, I do not believe it is absolutely necessary.

If you are serious about the advents, you might also find the following thread of interest.

"Advent experiment - mod - much better sound"

Good luck!

Marty

[tysontom]

When stacking Advents are the top units inverted to keep the tweeters fairly close together? If this is not done one would think that the rather distant spacing between the tweeters would cause some odd interference effects. With the top units inverted, the tweeters would form a short, vertical "line" over much of their operating ranges, which would help to reduce vertical radiation in the upper midrange and treble. No telling how the widely spaced woofers would intereact with each other, however.

Howard Ferstler

I believe that the old rule-of-thumb on stacking like-model speakers is to put the tweeters close together in the vertical-stacking arrangement. On the other hand, if the woofers are together -- with the tweeters at the top and bottom -- a phenomenon known as "mutual-radiation" causes the bass response (below the frequency of ultimate-radiation impedance) to rise about 3 dB all the way down to resonance. This is akin to placing single left- and right-channel speakers in the corners. Unfortunately, this rise in this overall low-frequency output does not give added bass extension; the resonance stays the same, but the output (relative to the midrange/treble) gets "heavier" and "punchier" as a result. With the tweeters at the top and bottom, other odd diffraction effects can occur. Using unlike models of a speaker, as in different vintages of the Large Advent, the only real issue might be efficiency, with one set getting more of the amplifier's output than the other set, but otherwise it should work fine.

Stacking mainly gives a system increased power-handling capability and greater "impact," it might also give the sense of a larger sound source with increased spaciousness.

--Tom Tyson

[jackfish]

[Zilch]

When stacking Advents are the top units inverted to keep the tweeters fairly close together? If this is not done one would think that the rather distant spacing between the tweeters would cause some odd interference effects. With the top units inverted, the tweeters would form a short, vertical "line" over much of their operating ranges, which would help to reduce vertical radiation in the upper midrange and treble. No telling how the widely spaced woofers would intereact with each other, however.

They are not mirror-imaged, and there is no vertical line. I have measured stacked Advents here:

http://www.audiokarma.org/forums/showthread.php?t=165025

The rational solution is to disconnect one of the tweeters and lowpass the bottom woofers as subs.

'Nuf said, lest the matter be retired to The Kitchen....

[soundminded]

When stacking Advents are the top units inverted to keep the tweeters fairly close together? If this is not done one would think that the rather distant spacing between the tweeters would cause some odd interference effects. With the top units inverted, the tweeters would form a short, vertical "line" over much of their operating ranges, which would help to reduce vertical radiation in the upper midrange and treble. No telling how the widely spaced woofers would intereact with each other, however.

Howard Ferstler

Why not toe one pair say the top pair in and the bottom pair out? Or better yet, make both bottom pairs and toe the outer pair out and the inner pair in? Then they would be Allisons....well kinda....sorta.....not. What if you did it the other way and toed the inner pair out and the outer pair in, would that give similar results? Or just turn both pairs around to face the front walls at angles, add a front 5" KLH table radio speaker and turn them into Bose 901 and a halfs.

BTW Zilch, your best efforts are lost on me. When I try to access it on AK, I get;

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Guess if you are not a member and can't give the sign, you're not allowed in. Somehow I'll just have to learn to live without it. Don't know if I can but I'll try my best.

[jackfish]

Obviously, the stacked Original Large Advents cannot sound good according to one set of measurements. I think sprucemoose in the AK thread has a good question about how they sound. There is a reason why people are told they must audition loudspeakers, preferably with the components they will use, to find those that sound good to them.

My setup includes stacked New Large Advents in a 11'9"x15'4" room with bass traps in the corners and absorption at wall and ceiling reflection points and behind the listener. The baffles of the speakers are 63" from the front wall and the center of the baffles are 39" from the side walls and 63" from each other. The interface of the cabinets in the stack are at listening ear level which is just outside of the near field (72"). I also have PeteB's 6dB "BSC" in the tape loop.

I think this setup sounds good. I listen to alot of music with it. However, I also know my hearing is compromised. How one's hearing relates to measured frequency response is worth exploring. I have a RS digital SPL meter and would like to put it on a tripod at the listening position and measure the frequency response of the system. What source is recommended to play the frequency spectrum?

[Zilch]

What source is recommended to play the frequency spectrum?

Sinusoidal test tones. The B&K "Ideal Response" chart provides the correction factors to use for each frequency when a dBC meter is used.

You also use EQ, as I recall. Getting this to work requires far more than sticking one speaker atop another, clearly; thank you for clarifying the point. We previously analyzed your setup more comprehensively, as well.

In the end, in the larger sense, stacking violates well-established acoustic principles and therefore, doesn't work. See this quote from The BAS Speaker, 6/77, re: AR "Live vs. Recorded" demo setup, posted in another thread here:

And last but not least, the loudspeakers: a single pair of AR-10's. Two-way speakers do not have the power-handling ability required. Multiple-driver systems, such as the LST, don't work, apparently because of interference effects between drivers covering the same frequency range. The same problem exists when more than one pair of speakers is tried. So: a single pair of three-way systems, located on the wall behind the drummer, about four feet apart.

[Zilch]

Guess if you are not a member and can't give the sign, you're not allowed in. Somehow I'll just have to learn to live without it. Don't know if I can but I'll try my best.

They're trying to tell you something, and thankfully, you got the message....

[dingus]

...In the end, in the larger sense, stacking violates well-established acoustic principles and therefore, doesn't work...

hmm, Large Advents are a decent speaker, they sound quite good and stacking them sounds even better, at least to many owners including myself. if you dont like how they sound that is your prerogative, but in the end this does indeed work for many regardless of acoustic principles, well established or not.

back on topic, the op was asking about matching stacked Advents. i've stacked with matching Large Advents and also with a pair of Large Advents and a pair of Advent 5002's. both trials resulted in similarly outstanding results. as others have found, inverting the top pair gives better results.

[jackfish]

Sinusoidal test tones. The B&K "Ideal Response" chart provides the correction factors to use for each frequency when a dBC meter is used. You also use EQ, as I recall.

Are these test tones available on a CD or must I download a program and run them through a computer? I have NCH Tone Generator. I would much prefer running them through my system from the CD player than from my laptop which has questionable sound card quality. I suppose I could make a CD of test tones using something like the NCH Tone Generator.

[jackfish]

Also, what EQ is available? Will REW do the job?

[Zilch]

Are these test tones available on a CD or must I download a program and run them through a computer? I have NCH Tone Generator. I would much prefer running them through my system from the CD player than from my laptop which has questionable sound card quality. I suppose I could make a CD of test tones using something like the NCH Tone Generator.

http://www.audiokarma.org/forums/showthrea...8877&page=6

Corrections for dB-C across the top of the B&K "Optimum" curve, below:

[justw]

You can find a suitable test cd here:

http://binkster.net/extras.shtml#cd

[Guest tim t]

You can find a suitable test cd here:

http://binkster.net/extras.shtml#cd

Helloo Jackfish, I am listening to my new large advents right now by themselves and really enjoying them, thing is i have for the previous year been listening to them with jbl lx44's stacked on top, last night i found, well i think i have found another set of new large advents recently refoamed just around the corner from me, i have A'd and B'd back and forth between the jbls and advents which are on the bottom and my final conclusion is.... the advents are much easier to listen too, the lx 44's have the titanium tweeter so they also make bad music sound bad, so i am hopeing and praying that tomorrow when this guy digs those babies out of his storage locker that they are NLA for $100.00 canadian refoamed already, yours look amazing, i also live in an apartment building, but the speakers are on the dividing wall between living room and bedroom and no one underneath me even though i am on the second floor, just covered carport and the laundry room so no real worries,. I did manage to sell my klh17's for a good price and my infinity QA's just love these KLOSS machines, the lx44's are very good, but colored in the midrange and like the advents the T30's don't like crappy recordings either, garbage in garbage out, i will post pics when i acquire them hopefully tomorrow. JUst another note, I have found a really easy way to re-oil these babies without using toxic products, as in chemicals that you do not want inside your house, i use grapeseed oil available at your local market, rubbed in with a cloth it works wonderfully. cheers to you all. tim

[Guest tim t]

Helloo Jackfish, I am listening to my new large advents right now by themselves and really enjoying them, thing is i have for the previous year been listening to them with jbl lx44's stacked on top, last night i found, well i think i have found another set of new large advents recently refoamed just around the corner from me, i have A'd and B'd back and forth between the jbls and advents which are on the bottom and my final conclusion is.... the advents are much easier to listen too, the lx 44's have the titanium tweeter so they also make bad music sound bad, so i am hopeing and praying that tomorrow when this guy digs those babies out of his storage locker that they are NLA for $100.00 canadian refoamed already, yours look amazing, i also live in an apartment building, but the speakers are on the dividing wall between living room and bedroom and no one underneath me even though i am on the second floor, just covered carport and the laundry room so no real worries,. I did manage to sell my klh17's for a good price and my infinity QA's just love these KLOSS machines, the lx44's are very good, but colored in the midrange and like the advents the T30's don't like crappy recordings either, garbage in garbage out, i will post pics when i acquire them hopefully tomorrow. JUst another note, I have found a really easy way to re-oil these babies without using toxic products, as in chemicals that you do not want inside your house, i use grapeseed oil available at your local market, rubbed in with a cloth it works wonderfully. cheers to you all. tim

[Guest tim t]

the guy who is selling the new large advents actually went down to his storage locker to take a look, yes! they are NLA recently re-foamed by sound hounds in victoria bc..and now they are mine to stack..holy sheet..so now i have what you have Jackfish...my apartment has old world carpet on top of concrete, it's a very long story how i ended up in this place, i cannot wait to place my new large advents on top of those that i already have....orgasmic....i know speakers, i used to build them, the boxes, the crossovers etc since high school and much more, so what you are doing with the baffles and b sc,m but let's stay in touch.../.Moi ...yamaha rx 596..and much more yamaha,, heavy damping i know but a wonderful reciever..most of my other stuff is also yamaha...what the hell they all work off the same remote.

[Guest tim t]

the guy who is selling the new large advents actually went down to his storage locker to take a look, yes! they are NLA recently re-foamed by sound hounds in victoria bc..and now they are mine to stack..holy sheet..so now i have what you have Jackfish...my apartment has old world carpet on top of concrete, it's a very long story how i ended up in this place, i cannot wait to place my new large advents on top of those that i already have....orgasmic....i know speakers, i used to build them, the boxes, the crossovers etc since high school and much more, so what you are doing with the baffles and b sc,m but let's stay in touch.../.Moi ...yamaha rx 596..and much more yamaha,, heavy damping i know but a wonderful reciever..most of my other stuff is also yamaha...what the hell they all work off the same remote.

[Guest tim t]

+Ok, so today picked up my second pair of walnut bullnosed new large advents, already refoamed by the top audiophile shop in town for $100.00 canadian, one of the cabinets is a bit rough on top a ding on the back etc the other had some issues too, so put the ones i bought today on the bottom and inverted the other pair i bought last year on top, oiled up the new ones with grapeseed oil, it's so easy and believe me it works, no smell, non toxic and the walnut just sucks it up, this 4 hours later and they are not sticky, or tacky, my first pair are A412168 and A412194 the new pair older only have one # though A401827, i see no reason to lookinside the other one at this point since both pairs were refoamed by reputeable shops just blocks apart, kind of funny in a way, so i lucked out both times, tested and refoamed for $100 bucks. So now the fun has begun, I have never ever heard anything quite like this!!! I knew that i was on to something with jbl lx44's sitting on top of the advents, but after bringing these babies home, shortening the speaker wires so that all are now equal, GAWD!! i have created a monster, someone else mentioned "a wall of sound" prior to my new additions when A and B ing the lx44's sounded lonely by themselves, the NLAdvents sounded lonely by themselves, stacking brings the unthinkable into the picture, it took me a couple of hours to realise what i now have, there is no need to turn it up, things are wonderful at twenty two, totally unexpected, bass, well too much, i can easily see how this configuration is called the "lease breaker" So i am enjoying all 4 of them, driven by a yamana rx 596 80rms /side one set on A one on B totally incredible, oh forgot to mention, i'm listening to cd's on the cd direct feature that yamahas have and when i listen to other stuff on pure direct everything is always set flat, it really is a very sweet little reciever, when i bought it i almost took it back to exchange it for the 7 series which is now discontinued it put out 100rms / channel, i was missing my pioneer with the quad darlingtons at the time, anyway, although i have never heard magnaplaners or electrostatics, i say that these stacked NLAdvents are the cats ass..and to that JBL guy.. what's his name, Oh yes I remember..Zilch, hey buddy don't diss what you havn't done! cheers and goodnight

[dingus]

..Zilch, hey buddy don't diss what you havn't done!

he's done the LA's, he just didnt like how they measured, the sound doesnt matter.

[Guest tim t]

So it's been a few weeks now and i am still totally blown away by my stacked new large advents, i see no need to modify them in any way, the sound stage is huge, i listen to classical, jazz and what ever, the more i listen to them albeit quietly because i live in an apartment building, the more i love them, even with movies they are huge, no need to turn up the bass or have sub woofer, i'm still working in 2 demensions anyway stereo, perhaps it's just the pure direct feature and the twin mono amps of my yamaha rx596, who knows, but when i go to cd direct, i worry about getting evicted, i cannot fault them in any way, i really have my doubts that if i walked into a very high end audio store that i could find anything even close inless i was willing to put out a huge and i mean huge chunk of money, all i can say is that this set up is awsome and grows on me everytime i listen and you don't need to crank it up to get good listening volumes. cheers.

[dingus]

So it's been a few weeks now and i am still totally blown away by my stacked new large advents, i see no need to modify them in any way, the sound stage is huge, i listen to classical, jazz and what ever, the more i listen to them albeit quietly because i live in an apartment building, the more i love them, ....

gee, i wonder how Zilch is going to measure that on his graph?

[Doug G.]

Even though I disagree with zilch re stacked Advents (I have four stacks in quad), I don't think we need to do this veiled denigration thing.

Doug

[dingus]

it wasnt meant to be veiled, but the point is well taken. Zilch seems to ignore the enjoyment side of the equation, or at the very least he puts the spec's ahead of the sound. the point i want to make is that he's off base when he tries to hold everyone else to his standard.

[Zilch]

it wasnt meant to be veiled, but the point is well taken. Zilch seems to ignore the enjoyment side of the equation, or at the very least he puts the spec's ahead of the sound. the point i want to make is that he's off base when he tries to hold everyone else to his standard.

I measure, I post; I hold no one but myself to my standard.

I also listen and enjoy, but know that has nothing to do with what the speaker IS. That's why you'll rarely find me saying anything subjective about how any speaker sounds -- I am no more reliable in this respect than anybody else. I like what I like, and you like what you like, none of which has any bearing on the facts.

FACT is, when studied under controlled conditions, central tendencies reveal themselves regarding listener preferences, and those are well correlated with objective measurements of loudspeaker performance. We each and all determine for ourselves whether that has any relevance to our individual experience....