The Ten Biggest Lies in Audio

[Darth Vader]

To give some idea, we run a >250VA transformer giving +/- 36v rails to deliver 120w RMS - and a large heatsink hanging off the back of the speaker.

That looks about right (quick approximation). 120w RMS ~ 168w peak and that gives a current of ~4.7A from a 36v rail. From this it can be derived that the load is summat like 7.7Ohms. Or perhaps me brain has fried.

Very oversimplified and not completely accurate but gives the gist.

Cheers,

DV

Just found a gramophone review:-

"Inside, the speakers each have a 75W amplifier for the tweeter and 250W for the mid/bass driver, according to AVI’s specifications, and ahead of these is an active crossover."

So perhaps that is the smaller amp in the photo?

Full review http://www.gramophone.co.uk/editori...ve-speakers-prove-a-viable-system-alternative

 

[Space is the Place]

That looks about right (quick approximation). 120w RMS ~ 168w peak and that gives a current of ~4.7A from a 36v rail. From this it can be derived that the load is summat like 7.7Ohms. Or perhaps me brain has fried.

Very oversimplified and not completely accurate but gives the gist.

Cheers,

DV

Is this into 5ohm? (not 7.7) Shirley Ashley said 250w into 5ohms? (what you really want is 1600w into 4ohm!)

According to the spec in HiFi Choice, the speaker cabs are 20 cm wide.

They must be at least 10cm dia.

 

[pure sound]

Its is about 12cm diameter looking at the picture, shirley if it were 7cm it'd be tiny?

According to the spec in HiFi Choice, the speaker cabs are 20 cm wide and 30cm high. I realise that the above pic shows a speaker on its side so the toroid might perhaps be 10cm. I still find the +/- 70V rail requirement needed for Ashley's claimed 50V RMS continuous across 8 ohms to be unlikely without any evidence of proper heatsinks. I think even calling this a 250W amplifier (44V RMS) is perhaps stretching credibility.


NB I am not making any comment here about the sound or build quality of these speakers. They look very neatly put together. I just read the thread & saw all sorts of claims being made & found some of them to be suspect. I might be completely wrong of course!

 

[Blzebub]

So RMS is half Peak then is it Ashley?

Jesus there's a lot of crap being talked here!

When AJ worked for ATC, they were known as Ashley Talks Crap.

 

[Space is the Place]

According to the spec in HiFi Choice, the speaker cabs are 20 cm wide and 30cm high. I realise that the above pic shows a speaker on its side so the toroid might perhaps be 10cm. I still find the +/- 70V rail requirement needed for Ashley's claimed 50V RMS continuous across 8 ohms to be unlikely without any evidence of proper heatsinks. I think even calling this a 250W amplifier (44V RMS) is perhaps stretching credibility.

NB I am not making any comment here about the sound or build quality of these speakers. They look very neatly put together. I just read the thread & saw all sorts of claims being made & found some of them to be suspect. I might be completely wrong of course!

I had the Opals and they had 270w into 5ohms on the woofer 50 watts on the tweeter, so about 330 watts for both continuous into 5ohms (so about the same as the ADMs 75 watts for the tweeters and 250 watts for the bass drivers). The amps in Opals take up half the inside of the speaker and of course they are much larger 11.6"W x 17.7"H x 10.8" and weigh 50lbs each.

http://www.eventelectronics.com/opal

 

[Darth Vader]

Is this into 5ohm? (not 7.7) Shirley Ashley said 250w into 5ohms? (what you really want is 1600w into 4ohm!)

No. These are Roberts speaker. He works for a company that makes hybrid-active speakers and I was just verifying that Robert was talking sense.

My speakers are nominally 6 Ohms but spend most of their time in the treble area where the impedance is ~ 2 Ohms. Each cabinet has seven drivers and one passive radiator that is loaded by transmission line to the woofer.

The sound is truly amazing for the size of speaker.

I have a 6L V12 XJS that can cruise at 150mph and is electronically limited to 155mph. It is effortless to drive and just doesn't 'see' the hills. Quite amazing with cruise control on. Unfortunately I have to follow the speed limits but that doesn't detract from the smoothness and relaxing driving. Ditto with amps. The more umph they have the more control and ease with which they can control the transducers.

Also one is LESS likely to fry a speaker with a powerful amp.

Cheers,

DV

 

[pure sound]

270W into 5 ohms is also somewhat different to 250W into 8 ohms as stated by Ashley. (post #630)

 

[Space is the Place]

No. These arent Roberts speaker. He works for a company that makes active speakers and I was just verifying that Robert was talking sense.

Ah right ok

I have a 6L V12 XJS that can cruise at 150mph and is electronically limited to 155mph.
Cheers,

DV

Cruises? Im surprised bits of chrome trim are flying off at that speed, not to mention a smoke screen of burning oil coming from the twin tail pipes!

 

[Space is the Place]

270W into 5 ohms is also somewhat different to 250W into 8 ohms as stated by Ashley. (post #630)

Oh yeah! lol. (that L300 pre looks amazing by the way!)

 

[prowla]

I found an interesting blog saying that peak is whatever you want it to be...

http://sound.westhost.com/power.htm

The author says, for example, "I have a set of computer speakers that are rated at 480W PMPO (yes - four hundred and eighty Watts). I have measured them at less than 5W each before clipping. There is no rhyme or reason that can explain such a difference, except ....".

(480W doesn't too far off 650W in the world of computer speakers and logarithmic scales.)

 

[Darth Vader]

270W into 5 ohms is also somewhat different to 250W into 8 ohms as stated by Ashley. (post #630)

I don't know what you folks are smoking but this is what Ash wrote in #630:-

"50 Volts and 10 Amps. W = VI so 500 Watts peak and 250 RMS."

Now lets oversimplify again eh? Ignoring important stuff like phase angles and see if its a goer.

Situation a) speaker drops to say 5 Ohm.

E/R = 50/5= 10A Check!
Power = I^2*R = 10*10*5= 500W peak = 500/1.414 RMS = 353W Check!

Situation b) speaker 8 ohms.

E/R = 50/8= 6.25 Check as within range.
Power = I^2*R = 6.25*6.25*8 = 312.5w peak = 312.5/1.414 RMS = 221W Check as near as dammit.

The impedance of a speaker does vary with frequency so the amount of power that can be drawn will vary with frequency.

They look a nice and neat speaker and I think might work well in a small flat.

Cheers,

DV

 

[mudlark]

That's about the point of much of bullshit marketing. It's all about hyperbole rather than much else. Why do Avondale and Naim and others have to put large transformers into their amplifiers to make them sound great when others put teeny transformers in and claim the earth?

Perhaps the best way to stop little amplifiers from collapsing under load is to use a chip signal conditioner that limits the frequency response giving the amplifier less to work with? How do these sets of equipment change from being a two way system into a three way system when you plug a sub woofer into an outlet plug? They don't I would guess. That would make these systems three way systems with no third driver.......

 

[pure sound]

I was asking what the continuous power rating into 8 ohms was. I still don't think that this power supply looks as though it could sustain 250W continuously into 8 ohms and particularly not if the included 75W amplifier was running flat out aswell.

Do you think it could? Is that really a 100% efficient 325 VA toroid & do you think it really does run 70V rails? You'd also need a heatsink for it not to catch fire.

 

[Darth Vader]

I was asking what the continuous power rating into 8 ohms was. I still don't think that this power supply looks as though it could sustain 250W continuously into 8 ohms and particularly not if the included 75W amplifier was running flat out aswell.

Do you think it could? Is that really a 100% efficient 325 VA toroid & do you think it really does run 70V rails? You'd also need a heatsink for it not to catch fire.

Remember that there are two amps in each speaker a 70w and a 250w. That photo may be the smaller amp but I just don't know.

What I am trying to do is see if the figures provided by Ash are within range and they are as near as dammit.

Also the ADM9.1 uses active rather than a passive crossover so are much more efficient and waste less power as heat in the passive components. Music is peaky and averages out to quite low power but demanding peaks need perhaps a thousand or more times that power for an instant.

Shit I'd never thought I would be supporting Ash!

Cheers,

DV

 

[Still]

Ash is the Michael O'Leary of HiFi.

 

[pure sound]

That photo is of both amps. The figures would be do-able but the hardware pictured & lack of an appropriate heatsink suggests wishful thinking imho.

I sell a 30W stereo amp. It will sit all day putting about 16-17V RMS unclipped across 2 x 8 ohm loads, both channels running. It's easy to measure & is the recognised way of giving a figure for power output. I don't claim that it's a 60W or 100W amp because it isn't one.

I was simply trying to get an equivalent figure for the amp Ash says is in these speakers. He gave a figure but I doubt it. That's all.

 

[i_should_coco]

Ash is the Michael O'Leary of HiFi.

Well, he does charge extra for bass. Apparently in the new AVI model, tweeters will be an extra cost option.

 

[Space is the Place]

The proof of the pudding is in the eating, the ADMs go louder with less strain than the 100watt Dynaudios (BM5A), the Dynaudios still have output down at 40Hz and are a enjoyable listen over a wider range of recordings and music, while the ADMs are starting to roll of a 65Hz which im guessing helps the clarity in the midrange (and is fairly good for matching with a sub, although i still think an unported enclosure and a dedicate high pass/lowpass crossover at 80HZ would be better) with no low bass to muddy it up!

In subjective listening to recordings of acoustic instruments or voices at realistic volumes the Opals knock them both into a cocked hat!

 

[Darth Vader]

That photo is of both amps. The figures would be do-able but the hardware pictured & lack of an appropriate heatsink suggests wishful thinking imho.

I sell a 30W stereo amp. It will sit all day putting about 16-17V RMS unclipped across 2 x 8 ohm loads, both channels running. It's easy to measure & is the recognised way of giving a figure for power output. I don't claim that it's a 60W or 100W amp because it isn't one.

I was simply trying to get an equivalent figure for the amp Ash says is in these speakers. He gave a figure but I doubt it. That's all.

Ah! Then these won't be continuous figures rather 'burts'. However since there are no passive bits between the amps output and the transducers rather less power will be needed to get an equivalent SPL. This capability should with good drivers result in a very dynamic sound.

I can vouch from my own experiments that as a system front-end/amplification/speakers gets more dynamic it sounds louder at lower spl. I use an spl meter a rather cheap one from Tandy OK for average and qualitative work but too slow to pick up the transients. As each piece of kit becomes clearer it actually sounds louder at lower spl/volume.

There seem to be some good reviews about on the web/magazines so if someone was in the market at this price then they ought at least be on an audition list.

Cheers,

DV

 

[Space is the Place]

That photo is of both amps. The figures would be do-able but the hardware pictured & lack of an appropriate heatsink suggests wishful thinking imho.

I take you mean the amps for both the tweeter and the woofer obviously! not for both speakers! There's one of them plate amps in each speaker.