Question about amplification for new Magnepan LRS speakers

[David Harper]

The old Rotel driving my Maggies might not pass muster here with ”only” 0.03% THD at its continuous power rated output but its current capabilities in low impedance loads is pretty awesome, 80A on 1 10 microsec pulse, 0.1 ohms (almost like shorted output). Needless to say, the only thing I’m blowing when I turn up the volume more than my ears can take is the Maggies 2.5A fuses. The amp is pretty much unperturbed. Every time I’m tempted to upgrade my end amplification (monoblocks perhaps?) I’m reminded that I have good, clean power aplenty already. The fact I only paid $350 for it, just because it had the tiniest scratch on its faceplate is a bonus.

0.03% is an excellent THD. Your old Rotel is an excellent amp. Every dynamic loudspeaker has distortion much higher than that so it is impossible to hear amplifier distortion thru any dynamic loudspeaker because the amp distortion is masked completely by the speaker distortion.Almost all loudspeakers distort badly at listening levels above 105 db SPL/1 meter. Even at lower listening levels most speakers THD will be on the order of 1.0 %.
So the distortion you're hearing from your speakers is 10 to 100 times greater than that of your rotel amp.

 

[Radiola9]

My experience with the LRS is not to waste my time with class AB amps. Class D amps have the power to break through the LRS's limitations. And they are free of colorations long associated with notch distortion and sluggish power supplies. Imagine 700 watts at 4 ohms and drive and stability down to 2ohms. THat's just a $500 Crown amp sold as a DJ component at guitar Center. Not exactly reassuring to an audiophile. Or if you want to spend money there are the Cherry amps, Megashino et al.. Selection of these components will improve as old designers grow old and die. But just listening isn't enough. Only through many listening sessions does an amp manifest itself psycho-acoustic wise. How it affects serotonin, for example, should be similar to what happens at a live session in a club or a concert.

 

[Sal1950]

Imagine 700 watts at 4 ohms and drive and stability down to 2ohms.

The thought of that much power into those little panels scares the heck out of me.

 

[LTig]

The thought of that much power into those little panels scares the heck out of me.

Nope - putting it into small voice coils with very limited heat dissipation scares me much more.

 

[Deleted member 2944]

My experience with the LRS is not to waste my time with class AB amps. Class D amps have the power to break through the LRS's limitations. And they are free of colorations long associated with notch distortion and sluggish power supplies. Imagine 700 watts at 4 ohms and drive and stability down to 2ohms. THat's just a $500 Crown amp sold as a DJ component at guitar Center. Not exactly reassuring to an audiophile. Or if you want to spend money there are the Cherry amps, Megashino et al.. Selection of these components will improve as old designers grow old and die. But just listening isn't enough. Only through many listening sessions does an amp manifest itself psycho-acoustic wise. How it affects serotonin, for example, should be similar to what happens at a live session in a club or a concert.

Hilarious first post on the forum. Bravo!

Power "breaks through the LRS's limitations." Who would have thunk it?

Dave.

 

[Wes]

Maggies has used 2 different amps at their own demos over the years. Early on they used Audio Research (their neighboring co. in Minn.), and later they used Bryston. Maybe they are still using Bryston, dunno.

Rather than hassle Wendell with a phone call, just use a good amp that can deliver high current into a 4 ohm resistive load.

I suspect it is only a matter of time before they come out with an active multi-speaker system...

 

[Sal1950]

Nope - putting it into small voice coils with very limited heat dissipation scares me much more.

No disparaging remark of the LRS was intended. I never heard them but I'm sure they are capable of delivering wonderful SQ as have all the other Maggie's I have heard over the years.
But there is a limit to everything. With a rating of 86dB / 500Hz / 2.83v, 700 watts would be asking for 114+ db from that small panel.
Not saying it's impossible but it does make me scratch my head a bit.
Maybe lice?

 

[Radiola9]

Hilarious first post on the forum. Bravo!

Power "breaks through the LRS's limitations." Who would have thunk it?

Dave.

Idiot..... the guy who expects to use maggies with a small amp.... that is lol

 

[Radiola9]

The thought of that much power into those little panels scares the heck out of me.

Dont look now. PS Audio has an 800 class d watts that is, entry into the market.

 

[Radiola9]

Maggies has used 2 different amps at their own demos over the years. Early on they used Audio Research (their neighboring co. in Minn.), and later they used Bryston. Maybe they are still using Bryston, dunno.

Rather than hassle Wendell with a phone call, just use a good amp that can deliver high current into a 4 ohm resistive load.

I suspect it is only a matter of time before they come out with an active multi-speaker system...

Oh... Dont both “ Wendell”........ nothing like name dropping experts. I know Wendell... Whoopie!!!

 

[Deleted member 2944]

Idiot..... the guy who expects to use maggies with a small amp.... that is lol

Well, one of us is an idiot.
You might have missed my posts #27 and #43.

Dave.

 

[Radiola9]

Well, one of us is an idiot.
You might have missed my posts #27 and #43.

Dave.

 

[Radiola9]

Talking about Wendell, he was helpful to me. When i got my maggies the grill cloth on one was sticking to the diaphram. Answer, take a roll of tape doubled back on itself and dab the edges of the problem until it gradualy breaks free.

 

[Sal1950]

Talking about Wendell, he was helpful to me. When i got my maggies the grill cloth on one was sticking to the diaphram. Answer, take a roll of tape doubled back on itself and dab the edges of the problem until it gradualy breaks free.

Did he give you a clue as to why the cloth was stuck to the diaphragm and if there was any possible damage to it from this situation?

 

[Radiola9]

No..... He did say this happens to a few new speakers and not to worry about damage. Maybe glue that is still a little tacky. It sounds fine now.

 

[Wes]

Oh... Dont both “ Wendell”........ nothing like name dropping experts. I know Wendell... Whoopie!!!

Wendell will readily admit he is not an expert.

While I am unsure of your point, you come across like an azz.

 

[Sal1950]

While I am unsure of your point, you come across like an azz.

Let's dispense with the name calling please.

 

[BogdanR]

Oh... Dont both “ Wendell”........ nothing like name dropping experts. I know Wendell... Whoopie!!!

Let me add to that. Almost 20 years ago (also establishing old ties apart from the name dropping, for a more complete picture) Wendell sent me a printed copy of their speaker setup manual at no cost to me.

 

[hen613]

I use an Audiophonics NC252MP (250wpc @ 4ohm) amp with my LRS. That is basically the cheapest NC252-based amp I could find. Room size is 20x18x7 and I sit about 6' from speakers. Listening volume around 55db max, due to having a very quiet basement. The amp has no problem what so ever driving the LRS. Without a sub bass is acceptable (LOL, relative to not having a sub).

DAC is a SMSL Sanskrit and streamer is Paradigm PW Link. I also use a Martin Logan Dynamo 800x sealed sub lowpassed at 50hz while running the LRS full range (don't have a way to highpass the LRS easily with my setup). It is interesting that while the sub is really only doing 20ish-50hz (with a room null around 30), it brings up the level of enjoyment (for me) much more than expected.

I played with speaker and chair positioning and used REW to measure the frequency response. Room positioning makes a measurable and audible difference. I strongly suspect as long as you got an amp that is not clipping, your room modes (I saw ~10db dips and peaks) will affect frequency response much more (in the low frequencies anyway).

 

[DonH56]

An investment in an inexpensive crossover to roll off the LRS' bass input might improve their sound. Something like a dbx 223 (analog) or miniDSP (digital). Long ago adding a sub to my little MG-I's (and rolling them off) made a big improvement in sound and I've been running subs pretty much ever since.

Can't drop Wendell's name, not sure I ever met the man. Met Jim something-or-other long ago; he was teamed up with some old tube company guy, Bill Johnson, or something like that. What's in a name?