Same watts at 8 and 4 ohms?

"Put it all together and you blew it once, and are blowing it again. Just not by as much this time"

Well, life is a personal journey....

I will probably get into trouble for asking this, but what I want to know is what one hears with a 17 Hz bass response like the talons?  How is that better than a speaker with a bass of 23 Hz? This is coming from the perspective that there is not that much recorded material able to provide 17 Hz. Maybe I am wrong in assuming that?

If you haven't found anything yet TMR has a NAD M10 under $2K smaller sleaker design in their Master series. 

what I want to know is what one hears with a 17 Hz bass response like the talons? How is that better than a speaker with a bass of 23 Hz? This is coming from the perspective that there is not that much recorded material able to provide 17 Hz.

You're right- but there are some recordings that do have that sort of information. There's a recording of the Saint Saens Organ Symphony on EMI that has 16Hz pedal tones. Its not the only recording with notes that low.

An ideal amp maintains the voltage output regardless of speaker impedance, which is synonymous with saying it doubles the wattage as the impedance is cut in half.


This isa good post.
Which is why I always ck the weight ofa  amp 1st, this tells me the size/quality of the transformer. 
Bigger the better,,up to say 80 lbs,, after that i can't lift the thing and not interested. 
Big hefty well built trans is what you want to consider,,I recall Marantz had some respectable power in certain models,, Then came along Rotel, NAD, Nacimichi,, Onkyo,, Onkyo and nac has a few amps with some solid power, Rotel, NAD were so over rated Sherwood , Snasui, Luxman, all so over rated on watts. So many ss amps sound anemic to me, I can lift most **100Watt* amps with 1  hand, completely ridiculous. 
 In hifi there are 2 types of amps
Real watts and fake watts. 
Its how beefy and well constructed are the trans. 
btw not only do i hate ss amplification,,I also hate as much low wattage SET amps. . best sounding speakers are all under 90bd, 4 ohm. Driven with real wattage  power. 

@n80 Have you contacted Aerial and asked for their recommendation?? They know more than anyone here about what might fit your use scenario and excel in doing so...

https://aerialacoustics.com/contact-us/

I have talked with the owner about other things but not this. I feel like the limitations I am up against (budget, size, room limits, intended use, etc) make it unlikely that he will be able to recommend something adequate for these speakers.

I have heard that he imports Gato amps. I cannot afford one of those. I have heard he endorses the Peachtree products. One of those is one the short list.

I'm waffling all over the place between going all out (makes no sense as I will not be using these often) and just getting rid of the speakers since there is no actual need for them to just getting a Sonos Amp which makes the most practical sense but not the best SQ sense.

Still not in a hurry. the Bryston still sounds wonderful, it has not sold yet and my wife hasn't made any threats.

@atmasphere "There's a recording of the Saint Saens Organ Symphony on EMI that has 16Hz pedal tones."

I've got the Telarc recording. I have no idea how low does it go or how low my system limbos, but when that organ blasts through my Aerial 7Bs, the house rumbles and you feel it in your chest even at moderate volume.


I might have to see if I can get a copy of the EMI CD.

I imagine you feel 16Hz more than hear it. 

I think you can see it. 

Ideally, a power amp should be able to deliver twice as much power at half the impedance. The way it can achieve this is if:

1) Its power supply can meet the demand (probably the most important criteria).
2) Its output stage/heatsinks are designed to dissipate the demands of the extra power.
3) It is still stable with the higher load (less impedance).

So, if it is NOT able to do it, most likely one or more of the above is suspect. Most of the time, it is the power supply inadequacies (item 1 above).

Amp should double.  More power is better.  Class A or A/B best.  Heavy is good.  All the aforementioned has never lead me astray!

Ideally, a power amp should be able to deliver twice as much power at half the impedance. The way it can achieve this is if:

This statement is false, on account of the fact that list following it is not what is needed. What is important here is that the amp is able to act as a voltage source and to that end, it does not have to double power as the load impedance is halved- at full power. Any amp that has an output impedance low enough will effectively double power as impedance is halved, with the exception of when the amp nears clipping. That is the only time that doubling power might be an issue, and only important if you have a low impedance load and you really for some reason need that last 3dB, which is not a very audible increase to the human ear.

This 'doubling down' thing is mostly marketing and **waaaaay** overplayed.

atmasphere,

You are right in saying that the internal impedance of an amplifier must be way less than the speaker impedance, in order to deliver power indirectly proportional to the speaker impedance. I took that as a given, since that is the case with most amps these days. However, if the supply line starts collapsing under the extra load, it will never be able to deliver the extra power, no matter what other parameters are tweaked.

This statement is false
This ’doubling down’ thing is mostly marketing and **waaaaay** overplayed.

This is the false statement, and is the typical statement of amp manufacturers that can’t double down with their amps.

However, if the supply line starts collapsing under the extra load, it will never be able to deliver the extra power, no matter what other parameters are tweaked.

Not just the supply, but the whole output stage as a well.

Use this comparison analogy
A 3000w Behringer https://djcity.com.au/product/behringer-nx3000-power-amp-with-smart-sense/?gclid=EAIaIQobChMIsLTX0viJ6wIV3sEWBR0v2w9eEAQYASABEgK3DvD_BwE
Verses
Old 25w ML2 monoblocks, https://img.usaudiomart.com/uploads/large/2229206-5c605986-mark-levinson-ml2.jpg
Both into a pair of the worst speaker loads known, the Wilson Alexia, but still very efficient at 90db, just a horror load.

To a given volume level the 25w ML2 will walk all over the 3000w Behringer for sound quality, control, image and depth.

Cheers George

Well, the Bryston sold. So at this moment I’m listening to the 6Ts in a bizarre little system.  Sonos Connect into Classe’ AV preamp into old Onkyo home theatre amp. Amp and pre on bypass. It is 75w into 8 and god-knows-what into 4.

It is certainly a reflection of my lack of audio sophistication but it doesn’t sound bad to me. Bass remains quite good. The main difference I notice is that the midrange seems thinner and less lush.

So far just listening at modest volume and the amp isn’t ‘hot’.

This will have to suffice until I get off the fence or win the lottery.

I doubt any amp can really double it's power with halved impedance. Most of the amps that say they do are actually underrated at the 8ohm impedance.

I doubt any amp can really double it’s power with halved impedance.

If you take literary then no, it would like perpetual motion then "impossible"

"Almost" double, it’s wattage is the operative word, 8 to 4ohms, 4 to 2ohms and in the ML2’s case 2 to 1ohm

Cheers George

I would still think the ML2 would be more than 25 watts into 8ohms. My vintage krell amp is 300 watts and is supposed to double, but it measured higher than 300 into 8ohm, so the manufacturer did underrate the amp to get to that doubling into 2ohm and under.

I would still think the ML2 would be more than 25 watts into 8ohms

They are, when keeping respectable 8ohm distortion figures, losses, as they only have 20v or 25v rails for memory.

Cheers George

Story time!!

Absolute Sound:

One of the Ten Most Significant Amplifiers of All Time

Stereophiles John Atkinson: HQD LOUDSPEAKER SYSTEM and ML2’s

I first heard the Mark Levinson HQD loudspeaker system some ten years ago, at the Festival du Son in Paris, in the days when it was a real hi-fi show. Perhaps even more so than by the speakers, however, impressive as they were with their stacked Quads, Decca ribbon tweeters and Hartley 24" woofers, all in beautiful beech woodwork, I was bowled over the amplification used: six Mark Levinson ML-2 monoblock power amplifiers. Capable of just 25W output each, these class-A monsters were the first true high-end amplifiers I had ever heard. The memory of effortless low-frequency reproduction, coupled with a magically liquid midrange, lingered on.

The ML2’s drove these double stacked Quad 57’s with Decca Kelly horn loaded ribbon tweeters from 10khz up, and used 2 x 24" Hartley bass units from I think it was 80hz down.
http://www.kaponk.com/2019/08/15/hqd-loudspeaker-system/

A friend Otto Major (rip) Quad 57 restorer guru. had this very speaker system, except the amp used was my own built 150w Class-A water cooled self contained mammoth of an amp, 2 preferable 3 man lift.
This system, it was something to hear. The Harley’s were mounted in the brick wall behind the Quads and they used the next room!!! as the speaker box. the FS was I think 16hz.

Linn LP12 Black Widow arm with the best cartridge I’ve ever heard a Stax CP-X Electrostatic cartridge.
https://www.vinylengine.com/turntable_forum/gallery/image/11682/source?sid=eefee7d56ce857f513c305e4e...
https://www.vinylengine.com/turntable_forum/gallery/image/11675/medium
That used a tube HT power supply. Here one dismantled for repair.
https://www.vinylengine.com/turntable_forum/gallery/image/15730/medium

https://www.vinylengine.com/turntable_forum/gallery/image/11679


Cheers George

invalid,

Here are some amps (more like welding machines) that can do double the power:

D'agostino Relentless.
Pass labs, almost all their amps.
Boulder 3050 monoblock,

and there are more......

@mt9894, one of my restrictions is that for these speakers to stay in the living room, the stuff driving them needs to be fairly small and discrete.

The H2O is only 14x14x 6-in tall. All black and one small LED in the front, it easily disappers.

If performance to you is most important then it can't be beat. Look at the inside in that 6moons review. You will not find that in any $2K amp and the ability to drive Scintillas.

If size and looks are more important then there's plenty of class-D amps that are simply modules thrown together in a shiny chassis.

You can't have it all.

Cakyol,                                                                                                 those amps are underrated on there 8ohm power specs there isn't any amp that can actually double it's output power, it is impossible. Like Georgehifi says it would be perpetual energy to be able to do that. I have a krell amp that claims that spec but it can't technically do it, it can come close but the lower in resistance the less likely.

I have a krell amp that claims that spec but it can’t technically do it

What a lot are doing is to underquote the 8ohm wattage to make the 4ohm look like it doubled.
  
You see it all the time now in the Stereophile spec bench tests, where the manufacturer says it’s 150w into 8ohms and 300w into 4ohms the gullible see this as doubling. Then Stereophile show the 8ohm is actually is 200w measured and the 4ohm remains still as 300w, nowhere near doubling then. It’s not illegal, but also not honest either.

I’ve been asking Stereophile to "call them out on it" now for ages in the measurements section, but at least they measure and show it for the reader to make up his own conclusions about it. Suppose they have to be careful where there advertising dollars are coming from, and not to rock the boat too much.

Cheers George

     Better amps have very robust power supplies that can provide the extra current required to double the power.  For example, an old 125/250/400 Audire Forte at 8/4/2 ohms respectively, has one 500 watt transformer and 4 26,000 mf filter caps per channel.  A very fine Bryston 200 wpc amp, of that era, has a 375 wpc transformer, and 2 4000 mf caps per channel.  Guess which one the bass drops out of at higher volumes, or with more demanding speakers.
     A pal bought a set of B&W DM 14's from me for his 125 wpc Marantz super receiver from the same era. He decided to get a second set, like he had heard years ago at my house, powered by this 125 wpc Audire amp.  The Marantz absolutely would not push all four to nearly the same volume, and it lost a great deal of bass, and pinpoint accuracy.  This reciever is stuffed with a tuner, a preamp, all kinds of switch gear, an FM dial, etc.  There was no room for a big power supply.  
     Ever wonder how a Marantz A/V receiver can push all those channels at 125 watts per?  I have one, It can't. It can move the sound around, but that is all.  A separate sub amp is absolutely required for this type of thing. 

     Two words:  Marginal power supply.  Compare a Superamp of its era, such as a 125 wpc Marantz, or a 125 wpc Audire or 200 wpc Brystom amp and you will hear. 
     Taking up space inside the Marantz is a pretty decent amp. for what it is, but it also has a tuner and dial, a preamp, all kinds of switch gear, etc. Inside the Bryston are two 375  watt transformers and 8 4,000 mf filter caps, plus 8 output transistors with heat sinks.  The Audire has 2 500 watt transformers, 8 26,000 mf filter caps, and 12 outputs. All newer Audire amps have many more outputs.  The sound is what you would expect, as is the actual power available.  Running 4 B&W's through these three, the first thing you notice is how much bass the Marantz loses at higher volumes, followed by the Bryston and the Audire.  The Audire is rated at 125/250/ 400 wpc at 8/4/2 ohms respectively, the Bryston about 300 at 4 ohms, and is not designed to run at 2 ohms. The Marantz just a wee bit more than 125 at 4 ohms, and shows it when pushed.
     Why do you think a 125watt x 5  A/V receiver (even Marantz) cannot pus a single set of speakers and a non-powered sub? 
     Weight can matter.  more stuff weights more, especially with big heat sinks.     Interestingly, my recently refurbished (At Bryston!) Bryston preamp runs hotter than my Audire amps did at full tilt pushing 4 inefficient. speakers. 

Danvignau what is your point none of those amps even come close to doubling down when impedance is halved. My krell has a 5kva transformer and 260,000 uf of capacitance and 56 output devices but it even can't technically double down on power with halved impedance.

Better amps have very robust power supplies that can provide the extra current required to double the power.

As I said before it’s not just the power supply, but the output stage as well. Especially the use of BJT (bi-polar) output stages in complimentary NPN/PNP push pull configuration over using complimentary Mosfets as the P channel is Mosfets weak one the N Channel is fine.

My krell has a 5kva transformer and 260,000 uf of capacitance and 56 output devices but it even can’t technically double down on power with halved impedance.

But it comes close

Cheers George

It does come close, but I need another one to vertically bi-amp my apogee duetta 2 speakers, they are very inefficient but sound great.

invalid,

Of course you can get more power.  It is ludicrous to think otherwise.  An amp is like (bit of an exaggeration to get the point across) your mains amplifying a 60 Hz signal.  If you connect a 120 ohm load to mains, you will get 120 watts, if you connect a 60 ohm load, you will get 240 watts, if you connect a 30 ohm load, you will get 480 watts, etc, until you blow your fuse.

AS LONG AS YOUR MAINS DOES NOT COLLAPSE AND YOU DO NOT EXCEED YOUR CURRENT LIMIT, you WILL get more power.  It is virtually the same in amps.  It is like supplying a 60 hz continuous signal.  As long as the power supply can supply the needed current, it will keep on supplying more power.  The limitation with amps is the heatsink/output stage design (transistor current limits), the maximum internal impedance and its stability at different frequencies.  The ideal amp (again, an asymptotic exaggeration) will even handle a short cirtcuit across its speaker where the current will be limited by only the internal impedance of the output stage.  This obviously will blow the transistors but you get my point.

No amp can do that it's virtually impossible.

invalid, georgehifi,

This is the spec page from D’Agostino Relentless welding machine.

https://dandagostino.com/products/relentless-monoblock.php

Please show/indicate to me where the ’incorrect’ or ’misleading’ information is.

invalid, georgehifi,
Please show/indicate to me where the ’incorrect’ or ’misleading’ information is.

No need to get your knickers in a knot, the only way to prove it is with independent testing, and not believing the manufacture

Like I said bet the 8ohm is under quoted just like his Progression Monoblocks are below.

Progression Mono:
D’agostino specs
8ohm- 500w
4ohm-1000w
2ohm-2000w

Stereophile tested specs
8ohm-595w
4ohm-943w
2ohm-750w (went into turn off protection mode)

It’s impossible to double exactly there are always losses, if it did it would be saying it’s like inventing perpetual motion.


Cheers George

The bigger the power supply and the bigger the output stage the higher the wattage into 8 ohms. They may spec an amp at 1500 watts into 8ohm but if it's actually measured by a independent 3rd party they always come up with a higher wattage than the spec sheet from the manufacturer says. Take my krell amp for instance it's spec says 300 watts into 8ohm but stereophile measured it at over 330 watts.

Building amps with huge power output is one of Dan D'Agostino's top priorities.  They are all advertised as doubling down into 4 and 2ohms.

Here is what Stereophile measured in its review of the Momentum Monoblocks:

Specified as having a maximum power of 300W (24.8dBW), the Momentum comfortably exceeded that rating, clipping at 405W into 8 ohms (26.1dBW), with clipping defined as the point when the percentage of THD+noise in its output reaches 1% (fig.5). Fig.6 reveals that the amplifier clips at 640W into 4 ohms (25.05dBW), while into 2 ohms (fig.7), the amplifier puts out 1115W (24.45dBW). As with Dan D'Agostino's earlier amplifier designs for Krell, the Momentum is a powerhouse!

https://www.stereophile.com/content/dan-dagostino-momentum-monoblock-power-amplifier-measurements

Like I said, impossible to exactly double. And understating the 8ohm wattage figure

But these are better "close to doubling" figures down to 2ohms than any Class-D’s or even linear Mosfets with complimentary push pull output stages can achieve.

The Momentum comfortably exceeded that rating, clipping at
405W into 8 ohms
640W into 4 ohms
1115W into 2ohms

And yes Dan D’Agostino’s Krells, and the Momentum’s are powerhouses, that others claiming to be and can’t should try to mimic.

Cheers George

This is the false statement, and is the typical statement of amp manufacturers that can’t double down with their amps.

This statement is false.

I recently serviced out a Realistic receiver with 18 watts. Even though it has no chance of doubling its power at full power, at power levels less than full output, it does so with ease, for the simple reason that despite its inadequate supplies and heatsinks, the amp behaves as a voltage source. Its only that last 3dB into half the impedance that is being touted as such a great thing- and really has very little effect if any on how the amp actually sounds.


Any conversation otherwise really points to not understanding how a voltage source works, and why its important. Now its been pointed out that no amp can really double its power at full output when the load is halved. This is true because of a thing called Ohm's Law. It has to do with the output impedance of the amplifier being finitely more than zero. Whatever that value is, it will always prevent the voltage amp from perfectly doubling power as the load impedance is halved ***at full power***.


Since actually doubling power at full power can't be done, how important is it? If sound quality is your goal, its likely that the amplifier topology will play a bigger factor in the sound of the amp,  on account of how it makes distortion, and how audible that distortion is, especially at lower power levels where the amp spends most of its time with real music signals. Its also unimportant because you can't operate the amp constantly at or near full power due to the dynamic nature of music. 

I bought my big krell amp because my apogee duetta 2 speakers are very inefficient at 80db/w. 

The big Krell current wattage doubling grunt is not really fully utilized here, great sounding amp still with these speakers just a bit of overkill.

Apogee Duetta 2 is one speaker that doesn’t need so much an amp that can "nearly" double all the way down to 2ohms from 8 and 4 ohms.
Because it’s load impedance is very benign lowest at 5ohms,
https://www.stereophile.com/images/archivesart/Duetfig1.jpg

But as you say it’s efficiency is only 80db and this just needs lots of watts, even high wattage Class-D and or linear Mosfet poweramps will suffice into these speakers.

Cheers George

hi,

I have a few thoughts, no answers,

1. consider selling those speakers now, then pick new or used speakers and amp together

I am a proponent of efficient speakers (close to 90db/w/m or above, they are) and nominal 8 ohm rather than 4 ohm, certainly not a fan of even lower (they are low).

Efficient speakers need less power, which puts you in position to need a lower cost amp. If you ever want to try a tube amp, the higher the speaker’s efficiency the better to help keep cost/size/heat down which also increases placement options.

2. features, remote volume and include remote balance. a very small balance tweak can make a surprisingly large improvement. you might want tone controls,

3. low volume listening is likely, so: automatic boosting of bass as volume is reduced is important to retain involvement. Enjoying a Jazz bassist, lower volume, bassist will progressively disappear, unless you compensate for your/our ear’s reduced ability to hear bass tones as volume reduces.

The industry stupidly named this optional control ’loudness’. It should be named ’low volume boost’. It needs to be properly implemented if automatic, or at least have a remote bass control you can adjust (then consider, how does it get back to normal? reset when power off/on? visible indicator?)

https://en.wikipedia.org/wiki/Equal-loudness_contour#:~:text=The%20Fletcher%E2%80%93Munson%20curves%20are,the%20Acoustical%20Society%20of%20America.



4. separate ’control unit’ (similar but not a pre-amp) for remote functions, then use ANY amp.

i.e. I use this discontinued remote control unit to give me remote volume/balance/automatic loudness compensation/input selection.

https://www.usaudiomart.com/details/649391586-chase-technologies-rlc1-remote-line-controller/images/1694271/

that one is sold, they come up for sale occasionally.

note: no pre-amp needed for any line level input. I use my preamp for phono, the preamp is then 1 of the 4 line-level inputs to the remote line controller, and then it outputs to ANY amp with no features. you could simply have a separate unit for phono eq now or in the future.

???? anybody know ??? currently available units available to do this.

Elliott, thank you for the thoughtful response. I will take it all into consideration.

However, right now and against the prevailing wisdom here is what I am going to do and why.

I am going to order the Sonos Amp for my birthday next month. Here is why:

Class D, 125w into 8, 200 into 4 and "4 ohm stable" for whatever that is worth. Right now I'm satisfied with 75w into 8 from an old Onkyo AV unit. The Sonos AMP will be a step up from that I suspect. If so I can live happily with it.

It is small, runs cool, nothing else will need to be attached to it since I can ditch the Sonos Connect and use it elsewhere. That means it will be discrete and out of sight and make my wife happy and be controlled entirely by my cell phone or hers. And that is important! She will use it if it is no more than using the Sonos app. And if she uses it then there is buy-in and that is good.

It comes with a trial period with free return shipping so no risk if it turns out to be a huge mistake.

It has balance, simple EQ and fairly effect "loudness" switch for low volume listening. Even with the Onkyo and even at low volume the bass via Sonos with loudness on sounds very pleasing to me.

If the Sonos Amp plus the Aerial 6Ts just don't work out I can try the Aerial 5Ts plus the JL Audio sub with the Sonos Amp but I would rather not since I'm not fond of subs and that is more room clutter to make my wife unhappy. The 5Ts and the sub are still for sale right now.

Sounds like a reasonable plan to me.  Please do report back on the outcome.

When a manufacturer claims x Ohms stable, all they are saying is that the amp won’t start oscillating (and perhaps blow up) when presented with such a load. It does not suggest how it will otherwise power, perform or sound into such a load. 

I'm good with the not blowing up part. That's a feature that I find reassuring. ;-)

Also, from what I am able to understand from this thread is that since I am not likely to ever use more than 50% volume and usually around 30% I should not be taxing the amp to any degree.

The Onkyo does not get any warmer than would be expected at these volumes.

Bottom line: If it sounds worse than the Onkyo then it goes back to Sonos at no cost and falls into the live-and-learn category.

I do understand that this amp is beneath the 'dignity' of these speakers.  And it does bother me a little bit.....I don't know why. Kind of like putting Prius tires on a Ferrari. It would still do a lot of what a Ferrari does well....but not what it does best.

And I don't want to sell the speakers. They cost me nothing and one of these days I might find an application for them in which they can be driven properly.

Don't know about the sonos but nowadays don't most amps go into some kind of protection mode before blowing up.? 

@unsound +1

I think you are definitely going to enjoy it, solid, sounds like you will have great features.

my bday is tomorrow, 72, congrats for your upcoming bday prize.

what Sonos amp are you getting?

Thanks and happy birthday. So far these speakers have sounded wonderful with several less than ideal component combinations and with my far-from-golden ears I think the Sonos will be fine.


I'll be 57. My mom says I've always been an old man.

Keep keep in mind that while most of the time amps can cruise by with minimal power demands, but when demands arise, they can be surprisingly exponential. If those demands are not met; it can lead to clipping and potential driver damage.