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Amplifiers known to be reliable for <4ohm speakers

davidsrsb said:
Speakers in a realistic room don't follow the same distance law and will give higher SPL than in free space.
85 dB average is already in hearing damage territory
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To put things into perspective see here Permissible Exposure Time for Noise SPL sound pressure level and duration Guidelines How long can a person endure a certain noise level before hearing damage occurs health sound level noise hearing ears impairment tinnitus damage - sengpielaudio Sengpiel Berlin

The dynamic peaks we see in music waveforms last but a tiny fraction of a second and will be a lot less intense than the musician playing the instrument will experience.

DV
 
In answer to the OP, I can vouch for any of the Quad pro 52x series or any variation of the Quad 606 (707, 909, QSP or Artera). But NOT the 405.

This assumes a constant 4r and not something that dips lower, although I'm sure the above would be safe into such a speaker.
 
Darth Vader said:
To put things into perspective see here Permissible Exposure Time for Noise SPL sound pressure level and duration Guidelines How long can a person endure a certain noise level before hearing damage occurs health sound level noise hearing ears impairment tinnitus damage - sengpielaudio Sengpiel Berlin
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Rather big differences between NIOSH and OSHA recommendations!

Also I note these limits are for dBA, which rolls-off the low frequencies and could lead to subwoofer installers into a false sense of security. I was dialling in my subs recently wearing -30dB Peltor earmuffs and still experienced discomfort after a few minutes of Periodic Pink Noise at relatively high volumes (hard to avoid when the controls are on the back of the sub!). I wonder how much attenuation ear protection actually provides at low frequencies given that a lot of it is conducted through the body. IME it doesn't have much if any effect on the often excessive bass experienced at rock gigs!...
 
ex brickie said:
I asked ATC direct and their reply is below

It would be safe to assume that the SIACD will run a little warmer driving a 4 ohm speaker but given that you state you will use them at low to moderate levels, I don’t think you will have any issue.

In addition, although the W8 are 4 ohm rated, from this review https://mcusercontent.com/d54a38bd8...9b-7090-e1ce6c17a590/W8_Hi_Fi_News_Review.pdf
it appears that the minimum impedance points are relatively high in the frequency range where there is less energy in a musical signal.

I don’t really understand all of what it means but it sounds reassuring :D. Why would impedance drop in the higher frequencies? Would it be more common in the bass region trying to push a bigger cone? ...
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A quite comprehensive (quite technical) review of the W8 is at Test Boenicke Audio W8 (audiophile.ch). And yes the measured impedance curve in Fig.3 (red) matches what ATC writes. IMHO the reply seems right although I know too little about 'speaker design details to answer the question.

The W8 impedance looks to me actually quite average overall for modern loudspeakers (including phase too). So any modern amplifier with decent heatsinking should handle them happily, IMHO. However, they are not very sensitive so I would say 100W minimum and even then they may not do party levels comfortably (but I did see the comment about low to moderate levels).

IME, whether a 'speaker is labelled "8 Ohms" or "4 Ohms" by a manufacturer today is often a marketing decision rather than a technical one. I certainly know some loudspeakers labelled "8 Ohms" that are worse to drive than the W8s. To really understand today how difficult a loudspeaker is to drive unfortunately needs much more research than most people want to do.

I applaud Boenicke for being technically honest but the "4 Ohm" label obviously does cause questions. Nevertheless IMHO the W8s are quite typical overall of modern mainstream impedance although much less sensitive than average.
 
Thanks @John Phillips - I found that helpful. Some of the other technical explanations were getting a bit beyond me (but still useful to others here I'm sure)
Reviews of the W8s show they do appreciate meaty amps - although the same reviewers were using amps like Trilogy at £15k which are frankly beyond the means of most people. (Before anyone comments, yes the Boenickes are more than many can afford too) .
Luckily I guess I would only need low to moderate volumes ..... I don't have funds for an expensive alternative amp!
 
ex brickie said:
Thanks @John Phillips - I found that helpful. Some of the other technical explanations were getting a bit beyond me (but still useful to others here I'm sure)
Reviews of the W8s show they do appreciate meaty amps - although the same reviewers were using amps like Trilogy at £15k which are frankly beyond the means of most people. (Before anyone comments, yes the Boenickes are more than many can afford too) .
Luckily I guess I would only need low to moderate volumes ..... I don't have funds for an expensive alternative amp!
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The question "will this amplifier drive that loudspeaker well" is one that has fascinated me for a long time. The answer is often not completely obvious and usually at best indicative rather than definitive.

[TL;DR]For those who are interested in what led to my opinion, a loudspeaker's EPDR (see Keith Howard's Stereophile article referenced in post #69) is an approximate measure of "how much thermal stress will an amplifier undergo driving it". KH has reported in HFN that 1.7 Ohms is a typical modern minimum (lower = more stressful).

The W8 (if I calculate correctly) has an EPDR of 1.8 Ohms at 3,500 Hz (typical but, as ATC notes, where music has relatively low energy). Other than that there are two 2.4 Ohms minima at 40 Hz and 350 Hz - better but where there may be more musical energy; and 2.1 Ohms at 20 Hz and below where you usually only get low organ notes. That's why I suspect the SIACD will handle the W8s unless you want party levels.[/TL;DR]
 
I think the efficiency of the speaker is more important than the load.
I just got a pair of vintage Sony Esl speakers, they are huge, sealed boxes with 4ohm impendace,
To my surprise my old Denon drives them effortlessly, and they make detailed music at very low volumes, none of my other speakers work very good at low volume.
 
My Pathos Classic One Mk III does pretty well. The lower powered Pathos Inpol amps are more fussy of course.
 
The reason for 4r speakers is quite simply because drive units are now predominantly 4r.

And yes efficiency has beggar all to do with impedance.
 
david ellwood said:
The reason for 4r speakers is quite simply because drive units are now predominantly 4r.

And yes efficiency has beggar all to do with impedance.
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What does 4r mean? If. as I think it means - ohms? then why not just say ohms. Ye get no brownie points for having read a post elsewhere and hoped ye could use 4r soon...:cool:
 
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