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What is Floyd Toole saying about extra amplifier power and headroom?

I've been reading Floyd Toole's "Sound Reproduction The Acoustics and Psychoacoustics of Loudspeakers and Rooms" and came across a passage that I wish he went into further detail about. It has to do with whether having amplifier headroom has any noticeable improvement in sq. He happens to be talking about getting the bass right in small rooms, but in doing so, he also touches on the use of a larger amp for extra headroom: 

Remedies for unacceptable situations typically included spending more money on a loudspeaker with a “better” woofer (without useful technical specifications, that was a lottery of another kind) and a bigger amplifier (for useless headroom ...

It's the last part ("useless headroom") that I'm curious about. I have notoriously hard-to-drive speakers (Magico Mini IIs). Although the recommended amplification is 50w - 200w, in my experience, that's a bit of an underestimation. I'm driving the Minis with a Musical Fidelity M6PRX, which is rated at 230w @ 8ohms. (The Minis are 4ohm.) The combination sounds excellent to my ears at low to moderate listening levels, but I notice a slight compression in the soundstage at higher levels. My listening room, while small, is fairly well treated with DIY panels made from Rockwool, sound-absorbent curtains, and thick carpeting. So I don't think I'm overloading the room. But I have wondered if an amp with far more power than what's suggested (more headroom) would drive the speakers with a little less effort.

Those of you familiar with Toole or with driving speakers with power to spare, what are your experiences? If I went with, say, a pair of monoblocks that drive 600w @ 4ohm, would the extra headroom address the compression I'm hearing at higher levels? Or am I wasting my time and, potentially, funds that would be better spent elsewhere? 

Thanks!  


128x128diamonddupree
diamonddupree's avatar
diamonddupree OP
75 posts
 
@tketcham according to the MiniDSP manual:  "Asynchronous XMOS USB input for streaming audio (up to 192 kHz)."

And for Toslink, it says, "Connect a single digital source to the optical (TOSLINK) connector. Thanks to its asynchronous sample rate converter (ASRC), all sample rates between 44.1 and 192 kHz are accepted."

What I'm wondering now is whether the sample rate limit is irrelevant if you're feeding the MiniDSP an analog signal. IOW, if I have the MiniDSP after my DAC in the signal chain, the DAC has already converted the digital file to analog, so wouldn't the DSP just pass along the analog signal to the amp that the DAC fed it? Or will it still downsample the file before passing it down to the amp?
cakyol's avatar
cakyol
940 posts
 
Here is how it goes....

If you have the money to spend, despite the diminishing returns, the more of something you have, the better it is.

So, having a 1000 w/ch amplifier is always better than a 500 w/channel amplifier, if you do not mind the cost.

It is kinda like the condom story.  It is best to have it and not need it, than needing it and not having it :-)

diamonddupree's avatar
diamonddupree OP
75 posts
 
@cakyol hahaha! condoms! who needs those? ;)
noble100's avatar
noble100
2,419 posts
 

    I'm still curious and learning about the Loki and DSP Mini.  I just have a few concerns I was hoping someone could help me with.
     As I understand them thus far from this thread discussion, the Loki operates in the analog domain and the DSP operates in the digital domain and uses digital upsampling.  My1st concern is whether I'm  correct about this?
     My 2nd concern is whether either of these devices utilizes parametric equalization (PEQ)?  If so, I think it's important to know that PEQ and room correction equalizing are great at attenuating specific frequency peaks in a room, since these reduce demands on a system's amp. 
     However, they're very limited in their ability to boost specific frequency dips in a room, since these can significantly increase demands on a system's amp, which has a finite amount of power.  For example, correcting/boosting a single room frequency dip at 25Hz could require a doubling of wattage or more.
     I think diamonddupree/DoubleD should be aware that a single device like the Loki or DSP Mini HD may be very useful but only a partial solution to his issue.  A completely effective solution will likely still require a much more powerful amp, at least a pair of self-amplified subs or perhaps even both.

Best wishes,
     Tim
diamonddupree's avatar
diamonddupree OP
75 posts
 
@noble100 thanks, I'm curious about much the same thing and will report back with results. According to @yyzsantabarbara the MiniDSP does have a robust parametric EQ capability that integrates with REW software. I won't be able to try that out until I pick up a mic, which I will most likely do after playing around with the unit for a bit.

My greater concern is the digital/analog processing of the MiniDSP. It ultimately may not be worth it for me if the unit bypasses the DAC functions of my Mytek Brooklyn DAC+. I'm hoping, by placing the MiniDSP after the DAC in the signal chain and using its analog inputs and outputs, it will preserve the analog signal coming from the Brooklyn DAC. Otherwise, it seems my nice DAC is being rendered useless by the MiniDSP. I'd rather have the Brooklyn converting digital streams to analog and not the MiniDSP. All I want the DSP to do is control the HP filter to my mains. I don't want to use it as a DAC. So we'll see.

As far as a higher-powered amp, it's still on my radar. And my sub is already self-amplified. My solution may wind up being the much more expensive JL Audio active crossover and a pair of monoblocks but I'm starting with the MiniDSP since it's relatively cheap. 
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