Subwoofer pairing with Revel F35/F36

[shadyJ]

@snakeeyes
So the reference I was thinking about is Dickason's LDC v7. Specifically what he discusses is a comparison of WTW (d'Appolito) as a 2-way vs the same configuration with a 2.5-way with one of the woofers (lower) crossed 1 octave lower than the other which crosses normally to the tweeter. In this instance, his modeling showed that the lobing you would experience in a 2-way WTW was lessened with the 2.5-way at the cost of increased asymmetry in the vertical dispersion. His contention is that the lobing in a traditional 2-way WTW is the lesser evil and is less audible perhaps than the resulting asymmetry in dispersion from the 2.5-way version.
His modeled polar plot for vertical dispersion showed a decided upward tilt in the 2.5-way speaker. His subjective listening experience using the same speaker, one set as a 2-way, the other as a 2.5-way, played mono and compared side by side, was that they shared a similar timbre, but that the image depth was lacking in the 2.5-way.

I cannot say whether this effect might carry over in any way to a speaker like the F35 or F36. I don't have the experience building or testing speakers to know what to expect. I think it is interesting though that Dickason dedicated a small space in his book to discussing this in terms of why and where drivers are placed on the baffle and the resulting effects.

My instinct is that using matching drivers with different XO points is not optimal, rather a comprimise to tease performance out of a complex system. In my mind, if you are going to the effort of building XOs with 2 different high-pass filters, you might as well go to the extent of putting a mid-woof in and building a bandpass filter, thus taking the risk of crossing woofers too high or tweeters too low completely off the table.

Perhaps @shadyJ can shed some light on this? Not so much geared toward a specific speaker, but in general terms?

Cheers!

I can't really add much to this very good explanation. It might be something that is easier to understand in the form of graphs though, especially for visually-oriented learners.

I would say that I don't think depth is a quality that the speakers can impart on the sound so much. My belief is that soundstage 'depth' is mostly a matter of the recording, not the speakers.

 

[ryanosaur]

Are Dickason's comments valid outside of that specific driver arrangement, tho?

Indeed, Lovin'! That's why I said:

I cannot say whether this effect might carry over in any way to a speaker like the F35 or F36. I don't have the experience building or testing speakers to know what to expect.

 

[ryanosaur]

I would say that I don't think depth is a quality that the speakers can impart on the sound so much. My belief is that soundstage 'depth' is mostly a matter of the recording, not the speakers.

Right?! Especially in Mono.

I'll see if I can find anything easy to link to later. Off to work now.

Shady, any experience testing 2.5 way towers? Any interesting dispersion anomalies, or whatever, that you can share?

 

[lovinthehd]

Indeed, Lovin'! That's why I said:

Just adding it as it isn't the same, was hoping shadyj might add to it....for the Revels or my 590s but Harman seems to use it in a few.....

 

[ryanosaur]

Just adding it as it isn't the same, was hoping shadyj might add to it....for the Revels or my 590s but Harman seems to use it in a few.....

Totally agree! I didn't get to audition any, but I did research several. It's definitely one of those things that I'm certain can be done well, just like a 2-way can outperform a 3-way. Always? No. But they can be done better!
Edit: quick side note, I think the MA Bronze 6 is a 2.5 way that reviews very well and I was very interested in that until I upped my budget.

 

[snakeeyes]

Totally agree! I didn't get to audition any, but I did research several. It's definitely one of those things that I'm certain can be done well, just like a 2-way can outperform a 3-way. Always? No. But they can be done better!
Edit: quick side note, I think the MA Bronze 6 is a 2.5 way that reviews very well and I was very interested in that until I upped my budget.

Did you demo the monitor silver center?

 

[shadyJ]

Shady, any experience testing 2.5 way towers? Any interesting dispersion anomalies, or whatever, that you can share?

Haven't measured a 2.5 way that I can recall. But the thing is, the dispersion anomalies would occur on the vertical axis, not the horizontal axis. It's not easy to run vertical measurements on tower speakers, which is why you never see any spin-o-rama measurements on towers in my reviews. So even if I had a 2.5 way tower, it wouldn't be clear in my usual measurement set that is the design under testing. But horizontal behavior is far more important than vertical behavior, so I wound't get hung up on 2.5 way vs 2 way for MTM speakers. I am guessing the difference isn't major so long as the lateral responses are good, and the vertical responses aren't appallingly bad.

 

[ryanosaur]

Did you demo the monitor silver center?

No, they did not have that at the shop I auditioned the Silver 500 and 300 at. I would have bought the C350 blind based on the performance of the towers though.

 

[ryanosaur]

Haven't measured a 2.5 way that I can recall. But the thing is, the dispersion anomalies would occur on the vertical axis, not the horizontal axis. It's not easy to run vertical measurements on tower speakers, which is why you never see any spin-o-rama measurements on towers in my reviews. So even if I had a 2.5 way tower, it wouldn't be clear in my usual measurement set that is the design under testing. But horizontal behavior is far more important than vertical behavior, so I wound't get hung up on 2.5 way vs 2 way for MTM speakers. I am guessing the difference isn't major so long as the lateral responses are good, and the vertical responses aren't appallingly bad.

Totally on board with this. Asking mostly as an academic exercise.
I kind of feel that a MTW arrangement might produce the same "phenomena" as Dickason described in the example above. Unless great care was taken with the XO, that is.
Thanks, Shady!

 

[Andrein]

I don't think that sub would be a great fit for some tower speakers. The reason is it will not be able to play deep bass very well, like stuff below 30 Hz. But your speakers can already take care of the range above that pretty well, so what's the point in getting a sub that can only really do what your speakers are already pretty good at? That's why I suggest a ported sub with a deep tuning frequency. They can make a far more significant contribution. The catch is that the sub must necessarily be a bit larger than a small sealed enclosure.

Why is it not a good choice? It is a small room and the sub goes down to 18hz -3db. Is it not capable to go to ref level plus 20db peaks?

 

[shadyJ]

Why is it not a good choice? It is a small room and the sub goes down to 18hz -3db. Is it not capable to go to ref level plus 20db peaks?

It's a small sealed 12" sub with a driver that doesn't have a lot of throw. It will run out of excursion very fast in deep frequencies. Yes, the response might have a -3dB point at 18 Hz, but only at soft volume levels.