We give up perspective to avoid tone controls

One of my full-range listening systems is my home studio where I have access to 3 different hardware equalizers, each in the 3k-$5k price range, (no not graphic EQs).  They all sound great, and they each sound different from one another.  Each can make music sound better when it's lacking in some area.   I will use EQ when playing vinyl that's had the lows and/or highs rolled off to fit the format..... and make mediocre pressings sound far more entertaining.    So what's the alternative?... To sit there bored to tears with flat sound and my purist morals intact?  Life's too short for boring sound.  My bypass button works just fine for the great stuff.

I have this problem with my main speakers-not my subs and dot ant to lose my good sound, going thru my subs as a crossover. I have a Casablanca 3, (just taking up space) I guess I could put in the tape monitor loop?? It's very versatile. Guess I need to invest in a good parametric EQ. I'm considering building a new sound room, if I move. Don't have the bucks to do it the acoustic fields way. Think I'll start a new thread. 

 @ erik squires—Phase matching of subs-to-mains should always be optimized at the applicable crossover frequency, and the measurement point to define the match should be located (precisely) at the intended listening position. When ported speakers are involved, crossover frequency waveform propagation becomes more indistinct, diverse, and increasingly affected by room-induced peaks and nulls that muddy the matching precision. (I use instrumented-means to accurately accomplish phase matching. If interested, request my related white paper. I am at geyer.bryan@gmail.com)

Sustained wide area phase matching is a fantasy, and any expectation that synchronized phase can persist over more than a small part of the home listening room, or beyond the limits of a given test frequency, is misplaced. This reality should not be construed as a significant shortcoming; refer 4.8.1 of Floyd Toole’s epic “Sound Reproduction”, 3rd edition (Routledge, 2018, ISBN 978-1-138-92136-8).

Phase matching of subs-to-mains should always be optimized at the applicable crossover frequency, and the measurement point to define the match should be located (precisely) at the intended listening position.

OK, with you so far...

When ported speakers are involved, crossover frequency waveform propagation becomes more indistinct,

<< cough >> No it doesn’t. The crossover frequency doesn’t move around depending on the sub's cabinet type.

diverse, and increasingly affected by room-induced peaks and nulls that muddy the matching precision.

Which is why you should deal with the sub’s overall response first, and then the crossover matching second.

Peaks and valleys are easily dealt with by use of bass traps and EQ, regardless of whether the sub is sealed or ported. Again, if you like sealed, that’s fine. However, the crossover frequency and how it matches the subs is at the top of the sub’s range, not the bottom, where the room modes are (hopefully) less frequent and severe.

What often confuses listeners is that the same speaker, ported, will go deeper, and therefore is more likely to run afoul of those room modes. The peaks and valleys you mention.

Sustained wide area phase matching is a fantasy, and any expectation that synchronized phase can persist over more than a small part of the home listening room, or beyond the limits of a given test frequency, is misplaced.

Which is weird, because this is the very opposite of what you are attempting to discuss in your first sentence. It’s also a point no one has brought up, but since you have ... this all depends on how co-incident the sub and main speakers are, the measurement area, and the crossover frequency. If the sub is directly underneath the satellites, this is hardly an issue in most listening rooms.

At 80 Hz, 1 wavelength is 14 feet long. A quarter of that is around 4 feet. That’s how much the distance must vary from ideal before you have significant change.  So if you have two subs and satellites are right next to each other, so that in the center of the room, they are equidistant, you'd need to find a place in the room where the sub was 4 feet closer  or further away to you than the satellite.  On the other hand, if you use a single sub, located in the center, then yes, listening directly to the sides is probably this far. 

And like I think you are trying to get to, those peaks and valleys will make a much bigger deal than microsecond phase matching of the sub. However, they are just as hard, or easy to deal with in a ported or sealed speaker which covers the same range. So far it seems to me you are conflating phase/amplitude matching at the crossover frequency with the rest of it, which I don’t really get.

Best,


E

E—Thanks for such comprehensive clarity; I generally concur. But my simple comment (that it's easier to phase-match subwoofers-to-main speakers when all speakers are sealed, not ported) was never intended to apply to idealized environs filled with bass traps and EQ correction. Nor did I intend that phase matching be conflated with time-of-arrival correction. It's generally not possible to accomplish the latter in the average home living room because decor dictates that the subs go into the room corners and the mains go up front, more centered. Given these typical limitations, it will always be easier to synchronize the phasing (at the xover frequency, at the prime listening location) if the speakers are sealed—not ported.

The extent of the phase convergence will be determined by the prevailing acoustics. In my own living room (no bass traps, strict WAF control), measurements indicate that closely matched phase won't prevail beyond a few feet from the prime listening location. Regardless, accurately phase-matching the subs/mains yielded significant audible improvement, and an instrumented means to accomplish the match was lots less tedious than doing tweak-and-listen trials.