i don't own any pass amps, but for that frequency range, the 250.5 would probably be best in my opinion. using the 60.5 for such a limited frequency range is like buying a ferrari to be your sunday grocery-getter.
8 responses Add your response
What is the brand and model of your speakers. Practically all mid-size and many full-size speakers can be driven by the XA60.5 alone. Each of the XA60.5s has 2 sets of output. You can separately drive the mid/high frequency driver using one and the low frequency driver with the other output. Basically you might not need the XA30.5 on top of this at all.
Thank you for the responses so far. The speaker is the Orion which is a Siegfried Linkwitz design is fully active i.e. each frequency band has to have it's own amplifier. The design is an open baffle dipole with 2 bass drivers, one facing forward and the other in reverse but wired in tandem. Currently each of these drivers is powered by it's own 60 watt amplifier. The specs of the driver are as follows ( please pardon all these numbers as I don't really know which ones you'll need to give me your opinion on this issue)
Nominal impedance Zn 8 ohm
Minimum impedance Zmin 4.9 ohm
Maximum impedance Zo 53.3 ohm
Resonance Frequency fs 18.9 Hz
Mechanical Q factor Qms 2.63
Electrical Q factor Qes 0.18
Sensitivity (2.83V/1m) 88.4 dB
In stock form with it's ATI amplifier, it is a excellent sounding speaker. However when I substituted the Pass XA 30.5 for the mid and high drivers it elevated the performance of the speaker to another level. My issue is to therefore get the lower end to be of comparable quality, hence the question.
Thanks again for the input
IMO, the XA-30.5 does not provide enough power to drive 88.4dB speakers unless you have a small room, and you listen at moderate volumes. It will run out of steam quickly.
The XA-60.5 would be a better choice for the mids and highs.
The better Pass Labs combo would be the XA-60.5 for the mids and highs, and X250.5 for the bass, IMO.
However, I question if you will hear benefits using the X250.5 as a dedicated bass amp versus, say, a more powerful ATI amplifier or one of many excellent Class D amps (like Bel Canto Ref1000 or a Wyred 4 Sound amp), or a used Hafler DH Series. That way, you could get the benefits of the Pass Labs XA-.5 sound, as well as good, solid controlled bass (something at which the ICE and Hafler amps excel), and all for less cash.
I suggest you call Pass Labs and ask them the same question. The thing is upper and mid frequency drivers don't take much power. It's the bass driver that wants a lot of juice. They might tell to do away with your XA30.5, but then they might not. As to the bass driver, I tend to agree with Tvad. However matching the timing and everything else between the higher and lower frequency signal might be an issue. Just call Pass. Since you already invest in the XA30.5, you might have to stay with Pass for the driving the woofer, say the X250.5 as several people have favored.
On the flip side, the combine cost between XA30.5 and X250.5 is about the same as XA60.5. So if Tvad is correct, you might want to sell your XA30.5 and just purchase the XA60.5 only for now. I did look at Siegfried Linkwitz website, and the suggested power for Orion woofer is only 60 w/channel. That is a very small demand for a woofer. What I'm get at is that your woofer is an easy one, despite the 8-ohm impedance and a good to excellent sensitivity of 84.8 dB.