Originally Posted by
boputnam
Doods...
First, thanks for the detailed postings and even more congrats for the 2-yr long exercise. That is devotion. You and Ian look to have done one hell of a job. I wish I had reason to travel to Reno...!!
The quote confuses me. I've "heard" that from but a few members here, and don't get it. Were you able to collect any measurements of the response, before and after?
No, I don't think Ed has an RTA or a Clio for pre 4344 post 4344 response.
Could you post some plots? Also, you didn't post whether there is any EQ in the signal path, and if so what it is, and what corrections you might be imparting.
There is no graphic equ I am aware of, however the Mac preamp has facility for eq via tone controls
I ask because I just inserted a Bryston 10B in-place of the Ashly - but not for the reasons you did, nor with the results you got. I am trying to achieve what I understand is Greg Timbers' ideal active crossover application with a 4345 - use the active crossover in a biamp set-up to replicate the voltage drive of the original HPF (-12dB, 290Hz).
This would be much easier to discuss verbally.
Question: What was your reason for installing it? (Are the voltage drives from the Bryston tailered to those of the passive 3145 crossover for the woofer to mid range driver?)
My understanding you were happy with the Ashly.
The passive filter voltage drive maybe difficult to emulate. The actual active slope is 18 db as you maybe aware prescribed by JBL. Perhaps if someone fluent with Soundeasy could take those passive voltage drives and compute an active eq simulation and schematic ..Tim G comes to mind.
We could attempt to modify the 12 db slope with the new crossover to match the current JBL passive voltage drive but this has not been attempted. I will look at it but it will take some time.
At any rate the 18 db slope in conjuntion with the active crossover is subjectively superior.
I have not yet Smaart'ed this - I am waiting Widget's visit this weekend for some A/B, and don't want to corrupt the current set-up before I go fully into the Bryston config - but what I did get (admittedly NOT properly EQ'd and therefore results/opinions are not relevant), is seemingly improved tonality, and better channel separation. I say not relevant because in my soundguy work, I typically am confronted with a system that sounds either muffled or bright, or "veiled" or boomy, and have found time-after-time that proper measurements of room response and adjustments for that response vastly improve the character of the sound, and the perception of the system (and audience response and appreciation!). This is experience based upon Smaart'ing dozens and dozens of systems, often when I felt there was either no hope, or it was already so good there was little improvement that could be made. Wrong on both accounts.
Interesting observations;On the basis that the L pads are setup correctly the distinction in Ed's system (or the reference system) is not relevent to Eq flatness. The veiling (we both observed) refers to loss of information and Hf brightness. This is attributable to what happens in the signal processing. This being insertion losses from cables and terminations, transparency of signal processing electronics and the power amplifiers.
The "brightness" many attribute to Bryston, IMO, relates to EQ. Bryston may be more efficient in their reproduction of the HF part of the spectrum - therefore, systems not "aware" of that will certainly sound brighter.
Could be the case! We found ther setting up of all 4 drviers far more critical in terms of level matching.
Perhaps a process of elimination may assist here. Temporarily bypass the Eq 1/3 direct from the preamp to the crossover=>and power amps. Then switch in the EQ in flat mode but not bypassed and then alternate with the Ashly and Bryston.
The brightness could also be attributable to the source or even the power amps. Also look at the net spl method of setting up the Lpads, it works.
I've got measurements before this switch, and soon will Smaart with Bryston and share those.