crazy idea - stacking identical speakers (JBL A130ies)

[al128]

hi there,

It is for quite some time that I am reading this forum, but I figured it's time to sign up now ...

I have been on-and-off into hfi since the mid 1980ies ... I do know my way (somewhat) around hifi now, as I have made many mistakes along the way ;-)


Having said that I have a Q:

for reasons that I don't want to dive into too deep, ( I can get A130ies fairly cheap, but the bigger stages like the A170 are way more expensive here), I have this crazy idea:

Running 2 sets of JBL Stage A130 in parallel, iow at the same time.

I poked around a bit and here's the plan:

• I did demo the A130 and liked them quite a lot .... I cannot demo the A170 and had to buy them "blind" - which together with the way higher price makes me uneasy
• so a could stack 2 pairs of Stage A130 - run in parallel at the same time to get a bit more ooomph from them (fairly big room)
• the A170 is a A130 with extra 5" woofer (and obv. more interior volume)
• my amp (virtue audio two.2) can be used down to impedances of 2 ohms ... so that fact that the impedance would drop from 6 to 3 ohms by running them in parallel should not be a problem
• I plan to run them stacked vertically - I understand that running them side-by-side is a no-no (for soundstage and phase reasons)
• putting the tweeter ends of the speakers together (so the top speaker would stand on its head) - to get the higher frequencies radiating from (nearly) the same spot and minimize any undesired resonances (suckouts or increases)
• I think I might get away by using the same speakers (as opposed to 2 different types)
• I figure if it's not working, I still can sell the 2nd pair of 130ies used at minimal loss - so not too much of a (financial) risk if it sounds like $h!t

at this stage the whole thing is more of a mental exercise (I'm not running out and buying 2 pairs tomorrow ;o)

so I'd definitely be interested in some educated guesses/thoughts/experiences for this kind of (possible) experiment.

So what do you think


best thanks for your time ;-)
cheers Al

 

[SIY]

Were you around during the Stacked Advents craze? Actually worked pretty well.

 

[antcollinet]

Be aware though that the 6ohm speakers may drop to 4ohm or below at some frequencies - especially bass frequencies. Can you get hold of the impedance/frequency chart?

EDIT - here it is measured by Armirm. Should be OK if your amp is happy at 2ohm

 

[More Dynamics Please]

I don't see the "way higher price" of a single pair of A170s vs. two pairs of Stage A130s. In fact at msrp a pair of A170s sells for $600, exactly the same as two pairs of A130s. Crutchfield currently has a JBL sale going with Stage A130s selling for $200 per pair and A170s for $360 per pair, so two pairs of A130s cost $400 or $40 more than a pair of A170s. I'd expect a pair of 2.5-way A170s to provide better overall performance than two pairs of stacked 2-way A130s.

 

[Ron Texas]

I had stacked Advents. They could get really loud.

 

[Doodski]

my amp (virtue audio two.2) can be used down to impedances of 2 ohms ... so that fact that the impedance would drop from 6 to 3 ohms by running them in parallel should not be a problem

I've never seen a system where running two pair of speakers in parallel for a grand total of 2 Ohms has not been a issue. Can you run them in series? This is not the biggest most robust of amps and 2 Ohms is most likely a stretch.

 

[NiagaraPete]

From my PA days. Stacking woofer to woofer bass bump, horn to horn, mid bump = louder.

I stacked LS35a’s at one time. Very nice but probably measured horribly. But we’re easier to drive.

 

[ahofer]

Were you around during the Stacked Advents craze? Actually worked pretty well.

When I worked at Atlantis Sound in 1978, we used to pitch stacked Philips speakers, as I recall. The store manager would tell customers he "sold his maggies for stacked Philips". He was lying, of course, but he lied about everything, when he wasn't threatening me (I was 14 at the time).

 

[Doodski]

We used to stack the RFT BR-26 and call it a B-52.

 

[More Dynamics Please]

Stacking speakers seems to have been popular back in the era before objective measurements became more sophisticated. Perhaps @amirm or @hardisj might for amusement try measuring with the Klippel a single speaker and a stacked pair for comparison in an episode of audio mythbusters.

 

[antcollinet]

I've never seen a system where running two pair of speakers in parallel for a grand total of 2 Ohms has not been a issue. Can you run them in series? This is not the biggest most robust of amps and 2 Ohms is most likely a stretch.

Series would halve the power, rather than doubling it. Obv would be much easier to drive as a result.

Alternatively get another identical amp, and run them in parallel, each driving one pair of speakers. Hopfully phasing between the two would match.

 

[Blumlein 88]

There is also front to back for creating a bipolar speaker.

Either way the higher frequencies will be the problem.

 

[audio2920]

I don't see the "way higher price" of a single pair of A170s vs. two pairs of Stage A130s. In fact at msrp a pair of A170s sells for $600, exactly the same as two pairs of A130s. Crutchfield currently has a JBL sale going with Stage A130s selling for $200 per pair and A170s for $360 per pair, so two pairs of A130s cost $400 or $40 more than a pair of A170s. I'd expect a pair of 2.5-way A170s to provide better overall performance than two pairs of stacked 2-way A130s.

Not sure about elsewhere but in Europe A170s are way more, and also, like a lot of Harman stuff, can be difficult to source.

For some reason the 130s are slightly more available, it seems. I think I can get A130s for (equivalent of) $320 whereas A170s are more like $750. That said, the cost saving still almost certainly isn't worth the compromise. I'd still just get the 170s. (In fact, I might do just that for a new low cost system I wanna put together....)

But it would definitely be an interesting thing to see if Amir could show us what the carnage of stacking might look like!!

 

[dshreter]

I really just don't think this is a good idea. The benefit of larger speakers isn't just that they go louder, they also have an extended bass frequency response. Your money is better spent on whatever larger speaker suits your use than getting double franken-monitors.

 

[hex168]

But I do wonder if nine A130s driven by a Denon X-4700H with Auro upmixing would sound better than any $1000 pair of stereo speakers. This would not be an easy thing to test. I suppose to take low frequencies out of the comparison, it should be nine A130s and two subs compared to a $1000 pair of speakers with the same two subs.

 

[al128]

I've never seen a system where running two pair of speakers in parallel for a grand total of 2 Ohms has not been a issue. Can you run them in series? This is not the biggest most robust of amps and 2 Ohms is most likely a stretch.

mine is red... the best sounding ones were the red ones ...

this amp spoiled all others for me ... (mind you, I'm not saying its the best amp out there - but good bang for the buck)

If anybody is interested, a short recap of highlights of this (then) $300ish amp

... can be run at 2 ohms, have a built in copper-heatpipe (which you can see in the photo -> the whole alu-case becomes a heat-sink) ... and came standard with a sub-out and with auricaps!!!!

... the jumpers you can see behind the volume knob are for bypassing the pre-stage - converting it actually into a poweramp and the 2nd pair of jumpers are to cut all speaker output under 80hz - again for outputting in a subwoofer scenario ...

but I digress ...

 

[Doodski]

the whole alu-case becomes a heat-sink

In pure theory the entire case does not dissipate enough power to make a difference. Only the immediate surrounding area where the heat pipe conducts heat to the case. The difference in temperature between the case and the heat pipe should be appreciable because of the low differences in temperature, conductivity and surface area.

 

[thewas]

putting the tweeter ends of the speakers together (so the top speaker would stand on its head) - to get the higher frequencies radiating from (nearly) the same spot and minimize any undesired resonances (suckouts or increases)

Still the tweeters will have several inches vertical distance making a interference lobing mess, the reason why you usually don't see 2 tweeters on even poor pseudo-D'Appolito implementations where even the distance of the mid drivers is already too large. In other words, I wouldn't recommend such a stack, unless you have already 2 pairs and want to have a party where usually no one cares about highest sound quality.

 

[AdamG]

Get a powered Sub, would that be a viable option? Better measuring and will give you the depth your looking for. Just tossing it out as something to consider.

 

[Doodski]

Still the tweeters will have several inches vertical distance making a interference lobing mess, the reason why you usually don't see 2 tweeters on even poor pseudo-D'Appolito implementations where even the distance of the mid drivers is already too large. In other words, I wouldn't recommend such a stack, unless you have already 2 pairs and want to have a party where usually no one cares about highest sound quality.

In the store with ~30 pair of speakers in a sound room we used to try various bookshelf speakers for stacking and some of them sounded pretty good when stacked. Keeping in mind the Yamaha amplifier variable loudness control was being used liberally.