Boston Acoustics 555x 575x 595x THX speaker package

Jason Kaufmann wrote:
> Does anyone own the Boston THX 555 and 575 THX speaker package,  if  so can
> you tell me the specifications, such as the frequency Response, Recommended
> Amp Power, and the sensitivity.

             watts  sensitivity         frequency resp   drivers
             -----  ------------        ---------------  ----------
fronts 555x  150W   90dB @ 1W 1m  8ohm   80-20kHz +-3dB  2*4.5" 2*1"
surrs  575x  150W   85dB @ 1W 1m  8ohm  125-20kHz +-3dB  1*4.5" 2*2.5"
sub    595x  250W   85dB @ 1W 1m  8ohm   20-80 Hz +-3dB  1*12"

These are the claimed specs.

Many years ago a common matching was the 555x, 575x, and 595x Boston Acoustics THX speaker set and the Kenwood KM and KC-X1 THX amp and pre-amp.

The rating for the KM-X1 was:

100W rating,
clipping 8ohm 140W headroom re:100W +1.5dB
dynamic power 8ohm 165W headroom re:100W +2.2dB

Also two 595x subs were commonly wired in parallel and connected to one of the six KM-X1's amplifiers. This setup played loud in my setup and I was able to play 112dB C pink noise without any distress in my listening room. Strangely other Boston owners could only get around 104dB C numbers from similar setups. I don't know why. But in anycase, 100W into a pair of 595x is underpowering them and I believe 400W to be a better match.

Also the 125-20kHz +-3dB frequency response for the 575x surrounds is not correct, like most other DPL surround speakers of their day, they started rolling off the highs around 8kHz which was OK back then (pre AC3). I thought the 575x dipoles were nice at the time but I wouldn't recommend them for an AC3 setup today.

The original Boston Acoustics THX speaker package was a nice setup at a reasonable price. It was loud, detailed, and far from harsh. Many high-end purists frowned on this setup, heck, to this day many of the purists dislike the whole THX concept but thats another story. Truth was, that for Home Theatre, this cheap Boston package blew away many so called "audiophile" owners setups and this disturbed them to no end.

Today I think Boston Acoustics is on there 3rd or 4th generation THX speaker package and it seems like most stores have dropped the line. THX seems to have lost a lot of the momentum it once had. Maybe the new 6.1 format and the Star Wars movie will return some of the THX glory. Maybe not.

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