The disappearance of the traditional amplifier

Thanks to all for the interesting discussion on waveguides in active monitors; it's given me much to think about and listen for.

However, I see no practical problem in rotating the waveguide in 3-way Genelecs as the MF/HF section still remains vertical. Because the LF/MF crossover is somewhere around 400 Hz (i.e. pretty low) there will be no practical difference whether vertical or horizontal, but of course the room reflection pattern will change due to different height of the woofer. The woofer directivity remains as it is and so does the MF, the only changing parameter is their relative position.

I find myself taking over the producer's role on a small-label classical production, and was thinking about these comments a couple days ago during a tracking session . . . the mains in this studio are horizontal soffit-mounted Genelec 1038s. I still feel that they're problematic in this configuration, and much of what I don't like is in this lower-midrange area that's likely related to the low/mid crossover region. It's bad enough where for the mixing sessions we'll either have to come up with a near-field arrangement that I'm happy with, or move to another facility. Either way, I was relieved that I was only making performance decisions through those 1038s . . .

Vertical mounting of course doesn't eliminate the crossover-related off-axis lobing, but it places it entirely on the vertical axis . . . and the vertical-axis listening position in the control room varies far less than the horizontal. Perhaps the use of brick-wall filters would reduce this, but I have no experience with monitors that use them.

Kirkus, if you can, try out a set of High Emotion Audio S-7s for near-field. They will give you very reliable information about what is going on in the recording- and no lobing effects if you happen to be off-axis. They have the widest dispersion I've seen- there are no powered speakers that can compete.

Vertical mounting of course doesn't eliminate the crossover-related off-axis lobing, but it places it entirely on the vertical axis . . . and the vertical-axis listening position in the control room varies far less than the horizontal.

Kirkus,

Good point. I agree tha this is an interesting discussion. Thx to you and to Kilopop and others.

However I woudl add that your point above is even more a problem for passive designs.

I would add that the advantage of Active speakers is that you can make a much sharper and phase compensated crossover filter precisely because it is active. This should reduce lobing. From what I know the 1038's allow the HF/MF combined unit to be rotated inside the cabinet for horizontal placement and this should ensure that any remaining lobing remains in the vertical axis where it is less significant.

Atmasphere, thanks for the recommendation - but for a number of reasons I'll probably be limited the BBS options (beg, borrow, or steal) . . . at least the nearfields in this control room are stand-mounted so they're easily swappable and moveable. Console meter bridge is also nice and low.

Shadorne, you make the excellent point that active designs can allow much more flexibility in the crossover design as well as more idealized response. But I think that the vast majority of both active and passive designs use fourth-order Lindquitz-Reilly alignments - and with analog filters this is usually an excellent overall choice. I believe that the 1038 also uses a fourth-order slope, and rotating the waveguide assembly eliminates the horizontal-axis lobing for the mid-high transition only . . . the low-mid transition is that of a horizontally-placed design.

the low-mid transition is that of a horizontally-placed design.

Yes but at 410 Hz (the crossover) the wavelength is about 2.7 feet (30 inches)! Given the drivers are only about 12 inches apart the lobing should not be apparent except at extreme angles (well above 60 degrees).

I wonder if you are hearing the effect of soffit mount - this has a significant impact on lower mids and mid bass compared to free standing (you no longer have comb filtering from reflections off the wall behind the speaker so that bass becomes solid, more tangible, more directional and less diffuse)