Combining multiple speakers as a single virtual unit


Thread Starter
Jan 10, 2021
Hi all,

As experiment, I was considering combining two 2-way passive bookshelf speakers as a single “virtual” speaker, with audiolense driving each bookshelf independently.

My “use case” is nothing more than the curiosity to experiment with a L/R/C setup for music stereo upmixes. A center channel matching my L/R speakers is the way to go, but before buying it I wanted to check out if I like the upmix concept at all.

The only speakers I have for the test are the above pair of bookshelves.
Of course, I could use a single bookshelf and call it a day.. but then, where would the fun of tinkering be? :)

Now, I know that using more than a single speaker for a mono signal is not recommended.
Nonetheless, I am curious if audiolense XO (and its time alignment) could make the above work.

I see three options:

1) “crossover option”: the two speakers would be on the same horizontal plane, adjacent; one would play lower frequencies (eg up to 600 hz), the other the remaining range (600-20kHz). Frequencies below 80Hz will be sent to a subwoofer.Basically a poor man’s 3-way; compared to a single bookshelf, I expect a bit more SPL and possibly lower distortion due to the woofers working on a reduced freq range.

2) same signal sent to both speakers, placed on a vertical axis (one on top of the other). Each speaker would be TTD corrected by audiolense (TTD per driver). My understanding is that this would be less terrible than having them on the same horizontal plane and fed with the same signal.

3) use a single bookshelf. No tinkering. Use the time saved from this weird experiment to listen to actual upmixed music :)

Curious about what experiment option would you recommend.



Staff member
Feb 5, 2018
The crossover option will work for sure. Not sure how alternative 2 will turn out, with two tweeters playing. They will most likely be slightly out of phase at very high frequencies. Not sure if this will have an audible impact, though.


Jul 3, 2020
My AV System  
Preamp, Processor or Receiver
Yamaha CX-A5200
Main Amp
Monoprice Monolith 7X
Additional Amp
Emotiva XPA-5
Universal / Blu-ray / CD Player
Sony (Universal)
Front Speakers
Magnepan MG12
Center Channel Speaker
Magnepan CC5
Surround Speakers
Magnepan MC1
Surround Back Speakers
Martin Logan Motion2
Front Height Speakers
Polk RT90 & Acoustic Research AR4C (parallel)
Rear Height Speakers
Polk RT90
SVS SB3000 (Dual)
Other Speakers or Equipment
Furman SPR-20i; AC Infinity controller and fans
Video Display Device
Samsung 4k UHD 65"
Streaming Equipment
HP mini-destop PC
Streaming Subscriptions
When i installed my 7.2.4 system last year I had 13 speakers to play with. Two of those are Acoustic Research AR4C sitting on top of 7' bookshelves flanking my TV. I had been using them as front presence, an option with my former AVR instead of rear back speakers, and especially for 'dialog lift' in my 7.1 setup . That worked well, and I knew I would miss them if I did not include them in the 7.2.4 upgrade. So, I wired them in parallel with my two new, front ceiling speakers. As most all my other speakers are 4 ohm, I didn't think turning two 8 ohm speaks into a 4 ohm circuit would be a problem, and it hasn't been. I am very happy with the effect. I think it broadens the Home Theater stage above, and just forward of, my TV
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