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Old 04-18-07, 10:49 AM   #1 (Link)
 
Malice
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Alias: Bob
Loc: Lytham-St-Annes, UK
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EQ'ing of main speaker bass drivers?


Hiya all!!

Recently I invested in a S/H Denon power amp to biamp my front speakers. Really pleased with the result. On the whole.

To summarise the "issue" I am trying to solve, I had accidentally left the PAMP turned off when listening to some multi-channel music with low bass content and my AV set to EXT-IN with Pure Direct, i.e. no bass management at play. To my surprise I found that the bass sounded tighter than with the PAMP in play. This is perhaps not too surprising given that without bass management my main speakers are producing 90db @ 26Hz on a 75db sweep in REW.

Anyway, as I have to take my mains pre-out to power the PAMP for the bass drivers in a biamp setup, could I introduce another BFD and use both channels to provide the same sort of EQ to my main bass drivers as I do to my sub?

Now I know there has been some concern or reservation about EQ mains frequencies, but let me explain a little about my speakers.

The B&W 604s3 have a tweeter, midrange and two bass driver units. In biwire or biamp setup, the 2 x bass drivers only are driven off the LF terminals. The tweeter and midrange are driven off the HF terminals.

The signal to the bass drivers effectively go through a crossover or high pass filter (or is that low pass, can't remember!) where the bass drivers have a 450Hz "crossover" with an 18db roll off. Now in addition to perhaps a BFD to tame the troublesome room-mode frequencies, I could also introduce a shelf filter which would mimic the roll off of the speaker at 450Hz @ 18db. In this way would I have a psuedo active crossover prior to amplification of the bass drivers? If so then that would also tend to improve the load on the power amp for bass duties only.

What do you think?


Bob

PS Sonnie, it was Floyd's DTS version of Wish You Were Here!!


| Sony KL-50W2 | Denon 3805 + POA-T10 Biamp| Denon 2900 | Pioneer 575-S | B&Ws 604s3/602s3/LCR600s3 in 7.1 | SVS PB12-ISD | BFD | Pinnacle Showcenter |Sky+(250GB) | Cables Scorpion & Mark Grant|

Bob - "Malice" was my Quake 2 CTF name

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