Lab.Gruppen E 4:2 Pro Amplifier Review

[Rja4000]

I was told 700w was the power required to be able to hear that symphonic orchestra at its full

You've read too much of Cabasse things

 

[carlob]

The 1U chassis mandates tiny fans which are almost always very noisy and that is the case here. While I have heard much louder, this is still something that is not acceptable in a standard home audio system unless you can place the amp in a different room.

Now this amp doesn't deliver at all but to be fair it is not meant to be used at home.

 

[Nango]

Ohh Sweden, "Kopf ab"!!!

 

[Ron Texas]

Kind of expensive compared to other pro audio amps.

 

[Tks]

Pro eh?

 

[F1308]

Pro eh?

Yes...Pro.
As you can see, that way of saying things only depicts the truth they meant to place into your mind was simply far away...Remember those TV sets with super planar screens: they wanted a flat surface to be used for their screens, but weren't able to do so. Now flat screens are everywhere and nobody says super planar nor even flat... just inches.

 

[RichB]

Yes...Pro.
As you can see, that way of saying things only depicts the truth they meant to place into your mind was simply far away...Remember those TV sets with super planar screens: they wanted a flat surface to be used for their screens, but weren't able to do so. Now flat screens are everywhere and nobody says super planar nor even flat... just inches.

True enough because flat is implied.
So now we look to black-level, off-angle viewing, burn-in resistance.
In video, technology has moved rapidly and with new technology we find new issues.
There was a time with color-points are 75% luminance was all that was measured.
Then folks discovered that linearity at different stimuli caused serious issues on some technologies.
They still do.

In audio, the same is true for audio as well. There have been class-D with issues into 4 Ohms or lower.
However, audio measurements are behind video measurements because video tools are a commodity.
The closest analogy is automated room correction but REQ some products do predictive measurements.
None do after measurements and none are used for component evaluation.

- Rich

 

[anmpr1]

Can someone explain simply what application this would be used for? An office or store use? To pipe in background music and an occasional intercom?

While perhaps interesting, what's the point of testing something like this? I really don't understand.

 

[F1308]

Can someone explain simply what application this would be used for? An office or store use? To pipe in background music and an occasional intercom?

While perhaps interesting, what's the point of testing something like this? I really don't understand.

That was a review and detailed measurements of the Lab.Gruppen E 4:2 "touring" pro amplifier. It was kindly sent to Amir by a member.
Then the testing started, without asking anything, and here it is for us to read...
Very nice indeed. Both, the review and the people involved.

 

[GXAlan]

While perhaps interesting, what's the point of testing something like this? I really don't understand.

Likely, the owner was just curious about its performance and @amirm was also curious. Curious is an important part of scientific endeavor.

https://www.the-scientist.com/perspective/curiosity-and-the-scientific-method-56061

 

[GXAlan]

I remember I was told 700w was the power required to be able to hear that symphonic orchestra at its full while playing their recordings at home..

https://www.etymotic.com/media/publications/erl-0022-1991.pdf

Peak RMS for the musicians is 115 dB. You don’t need to be louder than the actual musicians and in fact will be listening to a lower volume.

The JBL Everest DD55000 is a high efficiency100 dB/2.83V efficient speaker. 200W gives you that 115 dB at 15 feet.

The Revel Salon2 is 86 dB/W. 4000W gets you almost there.

https://myhometheater.homestead.com/splcalculator.html

Most people would say 105 dB peaks are plenty (and appropriate for hearing protection). That brings your amplification requirement to 15W and 400W, respectively.

 

[anmpr1]

That was a review and detailed measurements of the Lab.Gruppen E 4:2 "touring" pro amplifier. It was kindly sent to Amir by a member. Then the testing started, without asking anything, and here it is for us to read... Very nice indeed. Both, the review and the people involved.

I get all that. I just don't get the product's intended application. It's evidently for 'installed' sound. What is that? What kindo of installation? For a thousand dollars?

 

[Rja4000]

The real problem here is the massive failure (101 W measured) to meet the specified 200 W output in 8 ohms into "70 V" mode. In "Lo Z" mode it should deliver 100 W into 8 ohms, but it also fails at 85 W:
https://www.labgruppen.com/Categories/Labgruppen/Power-Amplifiers/Installed-Sound/E-4:2/p/P0DFD/Specifications#googtrans(en|en)

Well, given the fact that this is NOT meant to be stereo, we may think the 200W Total output power is for both channels cumulated.

I get all that. I just don't get the product's intended application. It's evidently for 'installed' sound. What is that? What kindo of installation? For a thousand dollars?

Well, as the presence of 70V and 100V suggests, it is meant to amplify buildings.
A lot of places have such things: train stations, airports, but also shops, and, in general, any public space, where one need to broadcast (usually) background music and/or messages to public. Can be used for security announcements too.

So reliability is paramount: you never touch it, but you want it to work when needed.

And it's not meant to be a stereo amplifier.
There are 2, 4, 6 channels amps and more.
It's just how you divide the (usually ceiling) loudspeakers load across the channels, for some kind of effective use of the available power.
Or to route different content (messages) to different building area.
This is described somehow in the user manual.

Which doesn't mean this could not be used for stereo. And measuring it is good for curiosity...
Actually, I'm surprised how good it measures

But it looks like there is a push towards getting higher quality sound also for commercial "installed sound".
Or at least to have customers paying more with that goal in mind. As explained in this marketing content from Yamaha.

 

[carlob]

 

[amirm]

Well, given the fact that this is NOT meant to be stereo, we may think the 200W Total output power is for both channels cumulated.

Their documentation is confusing but marketing material clearly says 400 watts total:

 

[Rja4000]

Their documentation is confusing but marketing material clearly says 400 watts total:

View attachment 70024

Yes, I agree. It's just that this is strange.

Those guys are saling Touring power amps that are recognized world wide. And, for sure, given the incredible amount of power they are specced for, that has been carefully checked.
So why would they cheat for a (relatively) cheap amp ? (But not cheap enough, still, to risk a reputation by cutting costs enough to be cheating by 50%)

I fully trust your measurements, that's no question.

 

[amirm]

I don't understand it either based on reasons you mention. Maybe something is causing the limiter to kick in that we (I) don't understand.

 

[carlob]

manual is here: http://www.marketing.labgruppen.com/webservices/dh.ashx?t=qv&v=8798

 

[Rja4000]

Just found those measurements of 1200w E12:2 model.
Same conclusion than @amirm.
A lot of additional explanation, though, as this is written for pro users.

But bottom line is clear:
"The E 12:2 is marketed as a “1200 watt” amplifier. With regard to the “heating power” of the amplifier (the best measure of output power when driving a resistive load), it’s no where near that. It’s more realistic to think of it as a 50 V or 70 V amplifier designed for use with high crest factor signals. The limiting circuitry prevents an overload condition that could damage the amplifier. The matrix makes it clear that it is still better to not load the amplifier below 8 ohms if one requires high fidelity for low crest factor signals, especially at low frequencies with both channels driven. This is not a subwoofer amplifier."

 

[Ralf Stocker]

Never heard of a Swedish company with audio expertise.