We should reject hard-to-drive speakers more often

It’s funny how them junk infinity’s as some call them

still sound as good or better in some cases then what is being 

produced today at 5 times the cost. Yes the crossovers was 

a pain to work with but back in the early and mid 80’s they was state-of-the-art the art. The IRS beta can go against about any 30,000 dollar speaker made today. And yes you should have to rebuild them now hell they are going on 40 years old. So yes stuff wears out. I own a set of Kappa 9.1 series 2 and I would put them up against any speaker made today under 15,000 dollars. 

I’ve owned many of the aforementioned hard to drive speakers and overall, they could not sound as natural and relaxed as an efficient horn speaker.

Interesting...I’m considering MBL 101E speakers, but I’m hesitant due to them being hard to try.

@ricred1 MBLs are easier to drive than they might appear. That is because they are omnidirectional and when measured, the microphone is placed 1 meter away from the speaker. Most of the output of the speaker is thus not picked up. Effectively in a room you can add 6dB to their rated sensitivity. So they can be driven be amps of much less power than you might expect!

OK, thinking about this this is less about the gear and more about the awe created by hard to drive speakers. Like we somehow want to make the speakers happy because they are so demanding. Maybe we should get speakers that are happy with any amplifier instead??

@erik_squires This is a good point.

I’ve been telling people for years now that the harder the speaker is to drive, the more distortion your amplifier will make. Especially with respect to lower impedance, this is easy to see in the specs of any amplifier. Its also audible by making the amp less detailed (since distortion obscures detail) and often harsher (since more higher ordered harmonics are created).

So what I tell people is that if high quality audio reproduction is your goal, your amplifier dollar investment will be best served by a loudspeaker of higher impedance (8 Ohms or more) that is also easy to drive (no weird phase angles and higher efficiency).

Lower impedance speakers have a hidden cost of the speaker cable being far more critical to best performance. Lower efficiency speakers suffer thermal compression in their voice coils. There are some attempts to mitigate the latter problem, but whatever the technique is can also be applied to higher efficiency speakers with no downside.

If your speaker requires more than 100 Watts to really make it sing, you have an impractical speaker! This is because of the logarithmic nature of the human ear (which is why we use deciBels). If 100 Watts won’t do, how much power will you need? To make the speaker play twice as loud subjectively, you’ll need about 1000 Watts. How many amps of that power really sound like real music without being oppressive? How many can afford that? For this reason, even very expensive loudspeakers are often fairly easy to drive.

The only real advantage of 4 Ohms might be that your amp can make 3dB more power if its a solid state amp that can double power into 4 Ohm as opposed to 8. So you have a weak 3dB argument for that, if sound pressure as opposed to sound quality is your goal- good luck with it; 3dB is a slight increase in volume to the ear...

So if you want a really decent, musical system, difficult low impedance loudspeakers should be avoided. It does not matter ’how good it sounds’ to you; if that same speaker were simply higher impedance it would sound even better (speaker designers take note of this simple method of causing your speaker to sound smoother and more detailed at the same time).

"@ricred1 MBLs are easier to drive than they might appear. That is because they are omnidirectional and when measured, the microphone is placed 1 meter away from the speaker. Most of the output of the speaker is thus not picked up. Effectively in a room you can add 6dB to their rated sensitivity. So they can be driven be amps of much less power than you might expect!"

Please suggest a couple of integrated amplifiers that can drive MBL 101e speakers.

Please suggest a couple of integrated amplifiers that can drive MBL 101e speakers.

My experience is limited to the mbl 101e. It was rated at about 81 dB which you would think is crazy inefficient. Its also a 4 Ohm load, climbing to 8 Ohms in the upper midrange. But it does not have any weird phase angles so there's that.

So add 6dB and you're at 87 which still isn't great, but that's a lot better than 81!

Now you have to figure the size of the room. In a moderate sized room most of the time a 100 Watt amplifier would do the job fine. So there you have a bit of info as to what to look for. I can't say more without knowing the room size and liveliness.