The Great Low-Frequency Deception - Philip Newell

[tuga]

An extract from Chapter 11 – Low Frequency and Transient Response Dilemmas – of Newell & Holland's book Loudspeakers For Music Recording And Reproduction:

The Great Low-Frequency Deception
‘Fantastic, true sounding bass: these small monitors tell you exactly what is on the recording’ – a statement typical of what you read in many advertisements, but it is often far from the truth. In fact it cannot be true says PHILIP NEWELL. At realistic monitoring levels, the low frequency response of small loudspeakers cannot be as accurate in terms of frequency response and transient response as a good large monitor system, flush-mounted in the front wall of a well-controlled room.

https://www.resolutionmag.com/wp-content/uploads/2016/02/The-great-low-frequency-debate.pdf

 

[GelbeMusik]

Yo, a 15" woofer has it easier to compress the air in that big enclosure, than a 7" has it, to compress its smaller one. That's why the distorsion, they say.

I would say, disqualified. But that's my humble opinion alone. Any great debate?

 

[hardisj]

flush-mounted in the front wall of a well-controlled room.

Even a standard bookshelf would benefit from this; but certainly a larger woofer would. That's an extra 6dB "gained" since you don't have baffle step to contend with.

 

[GelbeMusik]

Even a standard bookshelf would benefit from this; but certainly a larger woofer would. That's an extra 6dB "gained" since you don't have baffle step to contend with.

One might think so. But what if You wanna aim for Toole/Olive tilted in room response

 

[hardisj]

One might think so. But what if You wanna aim for Toole/Olive tilted in room response

Set a 1dB/octave HPF at 10hz. Duh.

 

[617]

Yo, a 15" woofer has it easier to compress the air in that big enclosure, than a 7" has it, to compress its smaller one. That's why the distorsion, they say.

I would say, disqualified. But that's my humble opinion alone. Any great debate?

Modern woofers don't really use the air pressure from the enclosure to aid linearity. LF transducers these days almost universally have big motors and stiff suspensions.

This article is not exactly outdated, but it doesn't reflect the best understanding of bass reproduction.

 

[GelbeMusik]

Set a 1dB/octave HPF at 10hz. Duh.

Still You need all the sound power as to energize the room. Alas, there is no benefit from wall mounting, once the Toole/Olive sound is decided.

 

[pozz]

Remember that his book was written for studio construction, not listening rooms. Studio construction is, in its way, a less flexible design process. Usually speaker locations are supposed to be in fixed positions due to constraints (so no separate subwoofer placement), and the ideal is point-source reproduction with mains speakers like Augspurgers, flush-mounted to avoid SBIR (which hurts both ideal transient response and linearity) and get a little room gain.

 

[Jon AA]

Still You need all the sound power as to energize the room. Alas, there is no benefit from wall mounting, once the Toole/Olive sound is decided.

I don't see one thing as being related to the other at all. Unless placing the speaker in the middle of a large room, you're going to get boundary reinforcement in the bass region--somewhat resembling the Olive preferred in-room curve to some degree. The main advantage of placing the speaker in a baffle wall isn't the relative amount of gain to a given placement, but its smoothness (no SBIR effects from the wall which often can't be fixed with EQ). And hopefully anybody ambitious enough to build a baffle wall will be using EQ in the bass to shape the gain as the user desires (even if that's the Olive curve).

Unless, of course, you're talking about rear ported speakers. Naturally, their performance would suffer from such placement. So don't use them if you're building a baffle wall.

 

[GelbeMusik]

... but its smoothness (no SBIR effects from the wall which often can't be fixed with EQ).

That's a maybe or not. But, ja, there is a chance of improvement. But not that there is considerable gain. as You confirmed, thank You.

 

[tuga]

That's a maybe or not. But, ja, there is a chance of improvement. But not that there is considerable gain. as You confirmed, thank You.

These two pieces make a good case for in-wall mounting:

Speaker Placement and Reflections from Nearby Walls
http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

The Truth About In-Wall Speakers
https://www.audioholics.com/loudspeaker-design/truth-about-in-wall-speakers

 

[GelbeMusik]

These two pieces make a good case for in-wall mounting:

It has been investigated e/g by Toole. The sources You gave, since Toole's publication, obviously must be seen as not correct in many aspects. As often with non-peer-reviewed articles, pure speculation is neither marked nor eliminated. But the addressed audience seems to take everything for granted, even contradicting stuff, even at the same time. So far my personal experience.

 

[A800]

Cone area/sound emitting area is still king.
I have good experiences with multiple 12 inch subs.
Anything bigger just didn't cut it for me.
PA speakers for "fast" high bass.
Car Hifi speakers for "slow" low bass.

 

[tuga]

It has been investigated e/g by Toole. The sources You gave, since Toole's publication, obviously must be seen as not correct in many aspects. As often with non-peer-reviewed articles, pure speculation is neither marked nor eliminated. But the addressed audience seems to take everything for granted, even contradicting stuff, even at the same time. So far my personal experience.

Blessed be the fruit...

 

[GelbeMusik]

Cone area/sound emitting area is still king.

Odd things happen in domestic set-ups. 30cm midrange-drivers for controlled directivity, 20cm drivers for bass extension. Whatever works. Maybe my tin-ears don't resolve the lack of ideal, but enjoyment with music is, ehm, great.

 

[A800]

Interesting.
I got to try this method.

 

[Jon AA]

But not that there is considerable gain. as You confirmed, thank You.

Everything is relative, so it depends upon the context. There certainly will be gain in the bass compared with free space, or placement of the speakers a decent distance from any wall.

It has been investigated e/g by Toole. The sources You gave, since Toole's publication, obviously must be seen as not correct in many aspects.

I don't really see much disagreement there though. From chapter 12 of his book:

The overall conclusion is that mounting this excellent little loudspeaker in a wall has left its overall performance substantially intact, but the bass output has been greatly increased, making it sound fat, thick, and tubby. After all, it was not designed to be used in this manner; almost all “bookshelf” loudspeakers are designed to perform optimally in a free-standing mode—sitting on a stand some distance from the room boundaries. The solution in this case is to turn down the bass. Any competent equalizer can do it, or the old-fashioned bass control may just be optimum if the “hinge” frequency is around 500 Hz.

What he does strongly recommend against (possibly what you're thinking of?) is mounting a speaker on a wall (one that wasn't designed that way). This will obviously cause the same SBIR problems pushing a speaker right up against the wall, not just the on axis dip but an abrupt drop in the sound power curve.

My point was it's extremely common for people to have rooms a bit smaller than they'd like, wives, etc, that keep them from having the speakers pulled out from the wall as far as you'd need to in order to completely avoid that problem. So, with speakers "too close" to a wall they end up with a problem similar to what he describes with on-wall mounting a speaker that wasn't designed for it. In this case, a baffle wall is an infinitely (pun intended ) better solution for having smooth bass/lower midrange.

 

[GelbeMusik]

Everything is relative, so it depends upon the context.
..
So, with speakers "too close" to a wall they end up with a problem similar to what he describes with on-wall mounting a speaker that wasn't designed for it. In this case, a baffle wall is an infinitely (pun intended ) better solution for having smooth bass/lower midrange.

O/k, on-wall is bad, in-wall is good. I referred to the first article. There the backwall alone is considered which, obviously, is not the complete picture. So, the article is of lesser use to people, who are not that critical (read: interested amateurs). Despite its, admittedly, best intentions.

The prob with on-wall mouting, or close-to wall positioning is the interference with some bounce. Mostly it's just one. But that it mitigated by the reflections from all other walls, and even from the single backwall with different angles and so forth.

To place some absorbent behind, as proposed, is quite ineffective, due to several reasons. Instead, it would, righteously, drive the cited significant other nuts.

These books … I read them all. They only make stop thinking. Most of its propositions are way to short fetched. That for I like Toole's book so much. It's most valuable statement is: there is no ideal, there is no original, there's not even a standard, it has to be fun. If it becomes too expensive, or otherwise too bothersome, You're definitely on the wrong track.

 

[Eminar]

Cone area/sound emitting area is still king.
I have good experiences with multiple 12 inch subs.
Anything bigger just didn't cut it for me.
PA speakers for "fast" high bass.
Car Hifi speakers for "slow" low bass.

Live bass nothing beats 8*10 ampeg fridge.
Kinetic bass punch to human wet sacks
4*10''s in parallel-series do fine though.
Equiv cone area to two 15in. But Responsive
Have you tried two 10's in Helmholtz push pull?
Car "HiFi" is oxymoron.

 

[A800]

Live bass nothing beats 8*10 ampeg fridge.
Kinetic bass punch to human wet sacks
4*10''s in parallel-series do fine though.
Equiv cone area to two 15in. But Responsive
Have you tried two 10's in Helmholtz push pull?
Car "HiFi" is oxymoron.

Yes.
Cone area of 4x10" is around 90% of 2x15".
I use 4x10" cabs myself.
2 of them are easier to carry around than 1 8x10".
No, not yet.
Car Hifi is possible.
Needs a lot of work, money and a DSP though.
The best sub I ever heard by far has been a Focal Car Hifi sub.
Utopia 33 WX.