Axiom Home Page Forums General Discussion Technical Questions book or floor with dynamics myth

I am always wondering which one is better, bookshelf+subwoofer and floorstanding speakers. The common answer is depends. With low to medium volume in a small listening room, bookshelf+subwoofer could perform as good as the floorstanding. In a large room, especially when playing dynamic media, you are better off with the bigger boxes. Here we assume that you have the room treated for sound reflection/ absorption, enough amp power and same pre-amp/DAC/media source.

Years ago, I paired M22V4s with 80wpc NAD integrated amp. It sounded good but distortion prevent me to push higher the SPL. I was told that the amp was taxed. So I replaced it with 250wpc Bryston 4b ST and add one EP500. It sounds better at high volume but there are still times I feel harsh sound for certain music.
Few days ago I tested M3V4s. There were few findings that made me think how the different media impact the performance.
1. How come the big sound could come from the little pretty boxes? I could push the volume up without too much worry about the distortion. I could play vocal, jazz, blues, solo instrument and even pop music with deep bass without issues.
2. The bass is very noticeable even though it is not supposed be according to the specs. Then I realized that it was because the sound is so clean so the bass is clearly separated from the mid-range. Once you could clearly hear the drum and bass, I guess that mentally you feel the bass and are satisfied. This could explain why some viewers said that a sub is not necessary.
3. But, the similar issue still exist when the volume needs to be turned down to play certain music, like symphony or something very “busy”.

So the question is: why? Why the "crowd and busy" media, like symphony or action movies where multiple instruments/sound sources produce different sounds at the same, would push the speakers to the limit, especially in high volume? While at the same time “less crowd and busy” media have no issue.

I am a Telecom engineer with some knowledge of sound/light/electronic-magnitude waves. No knowledge of speakers at all. So I just try to explain the reasons and hope some experts or even speaker designers could shed some light on it for me.

Definitions first. Sorry if I start to bore you, please skip them and jump to the conclusion.
1. In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
2. In sound, amplitude refers to the magnitude of compression and expansion experienced by the medium the sound wave is travelling through. This amplitude is perceived by our ears as loudness. High amplitude is equivalent to loud sounds.
3. Frequency in a sound wave refers to the rate of the vibration of the sound travelling through the air. This parameter decides whether a sound is perceived as high pitched or low pitched. In sound, the frequency is also known as Pitch. The frequency of the vibrating source of sound is calculated in cycles per second.

byjus.com/physics/characteristics-of-sound-wavesamplitude/

4. How do speakers work? As an audio signal is sent through the voice coil and the musical waveform moves up and down, the voice coil is attracted and repelled by the permanent magnet. This makes the cone that the voice coil is attached to move back and forth. The back and forth motion creates pressure waves in the air that we perceive as sound. For high frequencies, speakers must move very quickly. For loud sound, the cone has to move a long way. Distortion occurs when the cone move way beyond what it is designed to.
Here is a great website to understand how speaker make sound with animations. https://animagraffs.com/loudspeaker/

5. At any given time, the speaker produces just one note. If there two notes in the sound , they form one unified wave but your ear perceive two notes. If there are 20 notes in the sound, the unified wave will combine all of them so your ear can perceive the.

Analysis:

1. The speakers need to move fast enough to reproduce the sound. When you play a music with only 3 instruments plus a vocal, the unified wave is not very complex. Even you play it in a high volume, the bookshelf speaker with only one tweeter and one woofer could handle it clearly.
2. However when you play a symphony, you would have to handle a very complex unified wave. It means that the speaker has to move very quickly in a dramatically way jumping from one frequency to another in a very short time. If at the same time you play it in a high volume, the speaker may not have enough time to jump quickly from one frequency to another while the cone is at its further position to its middle location.
3. For floorstanding speakers, the workload is spread among more drivers. That means each driver is working at a half volume if you have double number of drivers than the bookshelf speaker. At a lower volume, the speakers handle the complex wave very well.
4. I call the less crowd/busy music as less frequency-dynamic music since it has smaller amount of notes. The crowd/busy music is high frequency-dynamic music since it has larger amount to notes.
5. I call the music with dramatic changing volume as volume-dynamic music.

Conclusion:

1. Good quality bookshelf speakers (with a sub) can play as well as the floorstanding speakers in a low to medium volume most of the time for most types of music. They also work well in home theatre setup because many workload go to centre/sub/surround speakers.
2. Good quality bookshelf speakers (with a sub) can also handle volume-dynamic music in a high volume to some degree.
3. Ggood quality bookshelf speakers may still struggle to reproduce frequency-dynamic music in high volume.
4. Good quality floorstanding speakers are needed to handle frequency-dynamic music in high volume.

Just my two cents. I might made some mistakes to comment on something which I am still learning.

Most of the time, people only talk about the volume-dynamic requirement which requires high power amp to avoid distortion. I am thinking that frequency-dynamic should be put into considering when choosing speakers.

I believe that Axiom's designers know it well:)

Hey Rock, nice work on that. Really interesting stuff. Really enjoyed that with the morning coffee.

I think the source / quality of the media being played makes a difference too in reducing or smoothing “ busyness”.

I might just be making this up , but I would think the cleaner the frequency is coming in the easier it is for the voice coil to work it’s magic , a clean leading edge. Thus reproduction of that signal has more “ resolve “.

Please correct me here as I have ZERO training in any of this. Just my own study.

Thanks for the encouragement. I am learning right now.

Your point actually completed my thought. Clean media source consists fewer but only accurate notes for the speaker to reproduce. Thus the unified wave is less complex resulting cleaner sound. Bad recording consists additional wrong notes which makes non frequency dynamic music into frequency dynamic music.

Couple of quick comments:

#1 - if you have small speakers/drivers at medium high volume you are pushing the drivers to the point of non-linearity where cone movement doesn't track signal. With enough design effort you can make the speakers keep sounding good in that non-linear zone (Ian mentioned this explicitly) but if I remember correctly when you have multiple frequencies at the same time ("busy content") then you get IM distortion once the driver moves into the non-linearity zone

#2 - IIRC there isn't a sharp divide between "linear" and "non-linear", more of an "it starts getting worse at zero" kind of relationship

#3 - I have always preferred bookshelf speakers when I was playing at volumes they could handle - it may be as simple as a smaller driver array providing better imaging with all other things being equal - but for clean "wall of sound" louder playback I always end up with floorstanders

#4 - one other contributor to good bass on the M3 is the base bump between 70 and 150 Hz from cabinet/driver tuning (check the frequency response curve under Specifications). I find it enough to be noticed but rarely enough to be a negative

#5 - my impression is that cabinet resonances can also contribute to "busy" content sounding worse than "simple" content but I strongly doubt that is a factor on M3's

It's arguable, but I still find M3's to be some of the most surprising speakers you can listen to in terms of the perceived clarity of sound. I say "perceived" because strictly speaking the other Axiom models offer even a bit more clarity in the upper midrange and because a bit of the perceived bass clarity comes from the bass bump, but the overall result is very (very) "listenable".

The M5HPs are still "better" in pretty much every respect but it would be really interesting to run a varied group of listeners through an M3 vs M5HP test and see what they prefer. My guess would be at least 50% preferring M3's.

Thanks for more insights and great info.

I made a mistake here where I tested M2v4 not M3. A typo. Sorry for that.

I guess that the floorstanding speakers have to deal with complex issues bringing by multiple drivers sharing the same spectrum of frequency. Bookshelf doesn't have that issue to deal with so the imaging could be better.

Let's say two tweeters produce the same note at the same time. However there are no identical tweeters in the world even they are manufactured by the same factory. The supposed same sound coming from multiple speakers actually are slightly different. When they are combined into the sound we hear, slightly different frequencies of the same note will make the sound less cleaner. That maybe the reason why imaging of even a small box like M2 with only two drivers could be so good.

You mention , Rock, at the start of your mini lecture, that assuming a treated room for reflections et al......

I wonder if it’s necessary to define the size of room or better yet ( my real question here) where does room measurement ( for volume cubed ) end?

For example, my main living space is 750 sq feet with 8 foot ceilings. There is a dividing wall with a large open pass thru “window “ into the kitchen. And an open staircase up to top floor to another 750 sq feet and sane stairwell down to the bottom floor.

How much of that volume cubed really matters ? Does the open spaces connected together matter in terms of needing to be pressurized by the speakers? Or do the little wall and corners and 90 degree angles cancel those out?

Does this idea of volume of space have an effect on “ clean and busy music? Am I losing out on clean as I lose “ linearity “ to these spaces?

I’m not sure if I’m explaining that very well. I understand that a larger space is desirable for good imaging and soundstage ( thanks mojo for helping me learn that ) but I would do better if I reduced the space to have lesser reflections by way of amount of volume cubed or by softer surfaces and absorption or both?

Wow. That’s a mouthful but I think you guys get the idea hopefully.

Short version: What room size and shape is ideal for full range listening with busy music and still having good imaging and soundstage and not over taxing the speakers and components into distortion.

Yes. Less drivers means better quality in terms of timing, assuming the tweeters are of relatively good build quality.

More drivers are said to producing comb filtering effects but I recall that being debunked to not really mattering in terms of audible effects.

Please correct me here anybody. I’m just going with what I’ve read and learned and may not be correct as my understanding is layman. Cool topic though.