Dunlavy SC IVA X-over resistor values

Jonathan, first off, I think you underestimate Dunlavy's build quality. Do you think John was hand building every speaker? No, but he had a staff to work on his assembly section. Every driver was measured (with a file kept on your speakers so long as they remained in business -- to allow for a matched replacement if needed) and crossovers were measured and constructed with care to maintain the time/phase design John Dunlavy considered so essential.

However, there are a number of tweaks performed on Duntech and DAL speakers. Here is a link that identifies several:

http://forum.audiogon.com/cgi-bin/frr.pl?rspkr&1028246710&read&3&4&

But you really have my curiosity, what is your cardboard on top of your speakers mod?

Respectfully to Shadorne, if DALs have a narrow dispersion then why is distance and angle from the sidewalls so critical, as well as the reflectivity of these walls?

My experience with DAL and Duntech speakers suggests two conditions. The speakers are of such quality that listening outside the "sweet spot" can still be very pleasurable. But I will admit that to optimize critical listening, where you sit will be important. And this relates to vertical position of your ears as well as horizontal position. This is because of the D'Apolito array of drivers -- think of them as a stereo pair turned 90 degrees and it should be obvious why placing your ears at tweeter level is important.

Back to Jonathan, for your DALs I would do everything that is practical for placement and room treatments before worrying about future tweaks to the speakers themselves. Just as with any quality speaker system, you should start with the environment where they are ask to perform.

Shadorne, I've read your response a couple of times and it does not make sense to me. Assuming you meant an unshaded light bulb (360 degree radiation) compared to a spot light (believe flood lights come in a wide variety of radiation patterns) in your analogy, it seems to me the opposite would be true.

From my reading on speaker placement, acoustics, and room treatments, it appears that a minimum of 10 msec delay is typically recommended for reflected sounds compared to direct sounds. This minimizes smearing and improves clarity. Now the narrower the dispersion (more focused, like a spot light) from a given speaker, the less the intensity of the sound waves reflecting off the sidewalls. Conversely, the wider the dispersion pattern, the greater the intensity of the reflected sound waves and the more important placement and/or treatment would become to satisfy the 10 msec or greater delay objective.

Both DAL and Duntech designs are fairly wide dispersion which is why sidewall reflections are critical to optimum set up.

John Dunlavy's placement recommendations:

Yes, John typically suggested long wall placement. This was (in part) to maximize speaker placement from the sidewalls. He recommended greater distances from sidewall to the center axis of drivers than from the front wall (long wall) to the front baffle board. Also he called for toe-in aimed just behind the listener's head.

However he did not recommend anything near 120 degree separation between speakers. He specified 45-70 degrees with 60 being the optimum. In fact he preferred an equilateral triangle placement of speakers relative to the primary listening seat. But since he also specified a 3-3.5 meter listening distance (for full convergence of drivers on his floorstanding designs), this results in greater physical separation of the two channels than some designers recommend.

My listening experiences with both DAL and Duntech speakers bears out the benefits of avoiding close sidewall placement.

And . . . I don't feel cross threaded on this at all. I just wanted to understand your perceptions on dispersion.