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

Hello diamonddupree,

     The Magico Mini IIs are world class performers as far down as they go down in the audible audio spectrum, which is about 40 Hz according to Magico’s published specs. The fact is, these are extremely high quality stand mounted monitors that may be without equal reproducing music within their less than optimum audible technical range capabilities of about 40Hz to 20,000 Hz, even though they likely extend a handful of Hz deeper at a handful of dbs down.
     In my opinion, the "slight compression in the soundstage at higher levels" you notice are most likely the result of your 2-way speakers’ 7" drivers, even though they are very technologically advanced in design and materials, being required to reproduce the midrange frequencies as well as the mid-bass/deeper bass frequencies simultaneously.
     Of course their rated bass extension is only rated at 40 Hz but these 7" drivers are still being sent even deeper bass frequencies to reproduce by your amp. Since your speakers are 2-way and not 3-way, they lack a crossover network that could send the bass frequencies below a given Hz to a separate woofer driver. Therefore, the 7" combination woofer/midrange drivers simply attempt to reproduce both midrange and bass frequencies up to the limit of their capabilities. When you raise the main volume control, this only increases the demands on these drivers to reproduce not only the midrange frequencies at a higher output level, but also the deeper bass frequencies at a higher output level simultaneously. Also more amp current is required to faithfully reproduce bass than midrange frequencies.
     Not surprisingly, these 7" drivers struggle to do both of these things at the same time. The sonic results? The sound quality levels of both the bass and midrange are compromised, especially as the master volume level is increased, and a compression in the overall soundstage is perceived at a minimum.
I seriously doubt an amp with more power, current or headroom is capable of solving the system sq issues you described. I suggest a better solution would be one of the following in order of effectiveness:

1. The addition of a high quality 4-sub distributed bass array (DBA) system, as briefly mentioned earlier by atmasphere, that matches the high quality of your Magico Mini II main speakers, such as the Audio Kinesis Swarm complete bass system reviewed on the link below by the Absolute Sound:
https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

     I understand you don’t think you have the space in your room to accommodate this, however, according to your room diagram I believe you do. The subs are each only 1’x1’x2’ and would be spread around the perimeter of your room with the drivers facing and only 1-2 inches away from the nearest wall. My main speakers only extend down to 35 Hz and this DBA concept works exceptionally well in my 23’x16’ room. It’s a concept that Floyd Toole, Dr. Earl Geddes and other experts recognize as highly effective because Geddes scientifically proved the concept and published his results in a peer reviewed White Paper, which is available online.

2. The addition of a 2nd sub, either another JL F-110 or even the addition of a larger JL F-112 sub. 2 subs typically perform about twice as well as a single sub in most rooms and the overall bass extension is usually perceived as being as deep as the sub with the deepest bass extension capability. The benefits of using multiple properly positioned and configured subs in a room, that begin to be realized with as few as 2 subs, are bass that is smoother, faster, more detailed, more powerful and dynamic as well as being better blended with the main speakers.  These bass qualities are increasingly more apparent as more subs are added to a given room up to a threshold of 4 subs, after which performance gains from additional subs in the given room typically become smaller and more marginal. 
       As you and others have mentioned, using some sort of active crossover filter device that restricts bass frequencies from being sent to the main amp/speakers, simplifies the setting of low-pass and high-pass crossover frequencies and enables subs to be more easily incorporated, can also result in improved overall system sound quality performance.

Tim

"One of the great challenges of this world: Knowing enough about a subject to think you are right, but not enough about the subject to know you’re wrong" - Neil deGrasse Tyson

Hello diamonddupree,

     After my last post, I think you received some good advice from several members on the benefits of multiple subs and active crossover devices.  I  run my mains full range and have my 4 subs low passed between 40-50 Hz.  I don't utilize an active crossover because I didn't notice a significant sq improvement when I tried one and reduced the bass sent to them.  I believe this was because my class D monoblock amps provide ample power, 1,200 watts each into my 4 ohm main speakers, and ample current, up to about 30 amps.
     I just wanted to let you know, however, that I believe you may perceive a significant improvement in sq in your system  by using an active crossover device like the Shiit Loki or DSP Mini to reduce the bass duties of your Magico Mini IIs.   I believe both these devices operate in a very similar manner but I'm not absolutely certain.  
      I also wanted to make sure you understand that utilizing at least a pair of good quality subs are also crucial for providing the high quality bass that will no longer be provided by the combination of your Magicos and your current single sub. 
     It's useful to think of the use of the active crossover device and dual subs as 2 sides of the same coin; they're both partially responsible for seamlessly integrating the high quality bass performance of dual subs with the high quality midrange and treble performance of your Magico Mini IIs.  
     They go together like hand and glove, Mutt and Jeff,  eric_squires and millercarbon as well as Trump and incompetence.

     If you decide to take this path as an upgrade solution, I'll share some more useful info and tips, that may be useful to you, along the way.

Tim  

    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

 Hello mrD,

     I really don't disagree with anything you stated.  I would just add that high efficiency speakers are not a requirement if you enjoy your music at hearing health threatening levels.  I know you didn't state otherwise but I thought some might mistakenly assume this.  I  personally  listen to music at about 70-90 dbs but on occasions I will go over 100 dbs when I get the urge.
     But I understand my speakers can safely handle very high volumes as long as the power is clean; it's normally high distortion and clipping that damage speakers.  My system is capable of playing at volumes well above levels I care to ever listen at but I like knowing my system's capable, consider it a sign of quality and view it much like a high quality car that's luxurious, a great cruiser on the highways, very powerful and fast when you feel the need but also gets good mileage when I take it easy.
     I have fairly inefficient Magnepan 3.7i main speakers driven by 1,200 watt @  4 ohm class D monoblocks that have very low distortion. I run them full range but also supplement the bass between about 20-40 Hz with 4 subs powered by a separate class AB 1K watt amp.  
     I built my system based on the concept of combining 2 systems:  a very powerful and dynamic bass system, that's also textured, tonally accurate and detailed, to establish a solid foundation for any genre of music along with a high quality pair of main speakers layed on top that provides very good midrange, treble and stereo imaging performance.
     The most difficult part, in my experience, is  getting the bass sounding right and seamlessly integrated with the main speakers.  My opinion is that at least a pair of good quality subs are a requirement for optimum results. 
     I've found getting the midrange, treble and stereo imaging sounding right is the easier part, especially if high quality and well matched amps and speakers are utilized and the speakers are precisely positioned in the room and in relation to the designated listening seat. Lastly, strategically placed acoustic room treatments work wonders.
     Overall, I believe diamonddupree has all the necessary component system parts to build a similarly very good system, possibly even better.

Tim

audiorusty:" Proper installation of your MiniDSP would be between your preamp and amps. IOW you would connect the left and right outputs from your preamp to inputs 1 and 2 of the MiniDSP. You would then send two of the four MiniDSP outputs to the inputs of your Musical Fidelity amp and one of the remaining MiniDSP outputs to your sub. Technically you could send both of the remaining two outputs of the MiniDSP to the your sub as long as the sub has both a left and a right input but I doubt if you would notice any difference.

Hello audiorusty,

      Very useful info but I'm still trying to completely understand how the DSP Mini operates. So in diamonddupree's system with his combination Mytek preamp/dac, he would just use a pair of standard/analog rca cables to connect the main left and right outputs of his preamp to the MiniDSP's inputs 1 and 2.  Then he would use another pair of rca cables to connect 2 of the 4 outputs on the MiniDSP to his amp. 

Questions: 
 He can use any 2 of the 4 outputs on the MiniDSP?
 How does the user know which output is the left channel and which is the right ch to ensure proper connections to the amp's l+r inputs?

     Assuming these 2 connections are somehow accurately l+r connected to the amp.

Questions:
Could the remaining 2 of the 4 outputs on the MiniDSP each be utilized as summed l+r ch mono bass outputs, with a single cable going to each of a pair of self-amplified subs?
Is there a method to configure the internal functioning of the MiniDSP for things such as assigning l+r ch outputs and the  low-pass/subs and high-pass/main speakers crossover frequency settings?

Thanks,
  Tim    

Hello diamonddupree and all,

     I was searching for more info on anything Toole has stated about amp headroom but couldn't find much. But I came across an older AVS Forum post along the way that I thought you and others on this thread may get a kick out of reading,
      It's from about 2003 and it describes his own home system at that time which is interesting.  And he even talks about a type of loudness wars in movie soundtrack mixing he noticed back then, in which the soundtracks were mixed for everything to be loud, the cinema operators would turn down the master volume in the theaters and, as a result, some of the dialogue on scenes was not loud enough.  It reminded me of engineers raising the overall loudness of cds and crushing the dynamics in the process.
     He used Revel Salon 2 mains positioned upside down, other Revel surround speakers and 4 subs in his system at that time.  Here's the link:

https://www.avsforum.com/threads/revel-owners-thread.710918/page-482#post-52485977

Tim

Correction, my monos are 1,200 watts each into 4 ohms

Tim

     I mainly agree with everything erik_squires stated in his last post.  My only disagreement is that in my practical experience, the use of 4 subs, properly positioned and configured in a distributed bass array (DBA) concept system, results in exceptionally good bass performance in most any room.  Just as Dr. Earl Geddes scientifically proved with his PHD thesis over 4 decades ago.   
     There's also no need for any bass acoustic room treatments of any type when using this concept.  Mics, room analysis and room correction equipment are interesting and can be utilized if preferred, of course, but I'm certain none of this was required in my 23'x16'x8' room  to perform at a very high level. 

      On another topic that danvignau posted about, I'm failing to understand why having an abundance of amp headroom in an audio system can be accurately considered to be anything other than beneficial by Floyd Toole or anyone else.  
     As a practical but admittedly anecdotal matter, I drive fairly inefficient, 86db/1 watt, Magnepan 3.7i  4 ohm speakers with 2,400 watt/30 amp class D monoblocks with an abundance of beneficial results and no negative results that I've been able to discern.

Tim