My final word on the subject (?)

Posted by: Jack From Adelaide on 04 May 2018

I imagine by now everyone is heartily sick of this thread but I thought I would add some thoughts about the things people have been posting about the update since I created the thread.

 

First a few things about loudspeakers in the context of hi fi. Every piece of electronics in a hi fi system is designed to produce the most accurate signal possible. The amplitude and phase must be as close to perfect as possible or the design is a failure. There is only one exception to that rule: loudspeakers. It is certainly possible to design loudspeakers which have a nearly flat amplitude and phase just like an amplifier. My speakers, which were the prototypes for the Duntech Prince loudspeakers, before the company was no more, have an amplitude response which is +/- 1.5 dB over a substantial fraction of the audible range. The phase is within a few degrees of flat. The speaker can reproduce a square wave from 500 Hz up to around 2500 Hz.

 

One of the most challenging things about achieving this is that (if you are using analogue crossover networks) you have to use a first order cross over. This is a very gentle rolloff and the drivers are audible over several octaves either side of the crossover frequency. So any deficiencies at the top end are still audible.

 

Another way to do this is the ingenious Balanced Mode Radiator (BMR) used by Naim in their current speakers. The idea is to not bother with a crossover and just run the midrange driver up into the treble. The problem with this (usually) is that for a given driver size, the relationship between the diameter and the wavelength dictated the directivity of the driver. In the BMR the high frequency performance is arranged so that the effective radiating area reduces with frequency. So the high frequencies only come from a little spot in the middle. Effectively the size of a normal tweeter with normal angular spread.

 

However, some loudspeakers are designed “by ear” and the frequency response is not flat nor is the phase. In fact the vast majority of loudspeakers have several phase wraps over the band.

 

Now why is this important? I am only guessing here, but I suspect that the new firmware achieves a higher level of perfection in the frequency response and phase of the signal than the 4.4 firmware did. So an accurate loudspeaker like a Quad ESL 63 and it’s ilk, the Duntech speakers, the Thiel speakers from the United States will sound wonderful with 4.6. I would also expect the Naim speakers with their brilliant BMR drivers would also sound good.

 

However a speaker which had a recessed treble or raised midrange might start to sound rough or “shouty” with this firmware simply because the frequency response of the speaker suits the 4.4 firmware better.

 

There is no right answer here. The world of loudspeakers is varied and the approaches are many. That’s why they exist. Some people just love the accurate loudspeakers (like me) and some like the characterful loudspeakers which add something extra to the music that isn’t in the recording.

Posted on: 05 May 2018 by Huge

Unfortunately when you put your +/-1.5dB speakers in a normal domestic room (or anything short of an anechoic chamber) the overall response them morphs into something more like +/-4dB (1/3rd octave smoothing) if you use acoustic room treatment, and more like +/-7dB to +/- 12dB in your average untreated domestic room!