There is not a BHK250 2 ohm load rating listed in the owners manual. The manual states “stable for musical transients”. Is there any reason for concern? Is there a significant drop off in transient power at 2 ohms? Many amp brands for many years list their 2 ohm rating. Thank you.
Do your speakers drop to 2 ohms at any point? What is your concern?
My B&W 801 matrix series do not. But, when listening to classical piano music I like all the headroom I can get. But mainly asking for future reference if possibly changing to other speakers. Thanks.
Taking into account impedance AND phase angle they might, and at differing frequencies.
That is what you should try to find out, most speakers are not too bad, but some are.
Some magazines like Stereophile, HiFi News and Record Review routinely publish this information.
There is lots of info on the web to explain it but Stereophile did a couple of articles to indicate that understanding the measurements does help with understanding the performance of the speakers AND the demands they will impart to the amplifier(s).
Here is pt1
Measuring Loudspeakers, Part One Page 6 | Stereophile.com
The BHK’s are generally ok. That they are listed as stable into 2ohms for musical transients tells you , at extremes they are limited. How often you might encounter these extremes is likely determined by a number of factors, including;
the speaker impedance/phase angle profile,
the efficiency of the speakers,
the frequency content of the music you listen to,
the size of the room & volume you listen at,
overall gain of the system.
frank7036,
Thank you so much for the information and link. I was able to read the informative measurement article. I was also able to find updated Stereophile measurements for the B&W801 Matrix series 2 which is not much of a different speaker the series 3 which has a slightly softer sounding tweeter. Very helpful information.
One interesting comment about the Series 2.
At an estimated 87dB(B)/W/m sensitivity, the B&W 801 is average in this respect. But as can be seen from the plots of its impedance magnitude and phase (fig.1), it is a fairly easy load for the partnering amplifier to drive. The magnitude hardly drops below 6 ohms, and while the maximum electrical phase angle (53.6 degrees capacitive at 2.8kHz) is fairly extreme, the impedance at this frequency is very high at 15.3 ohms, which will mitigate any negative effects.
Thanks Again -
Steve
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I drove a pair of B&W 801’s with an Airtight ATM2 tube amp and there was absolutely no problem driving them what so ever, even at high volumes
The BHK 250 shouldn’t have any problems driving them at all.