Why a 3" driver can give "good" bass

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#21
Ryan, I took your prior comment (#16) as addressing "little drivers" in general -of course without qualifying or specifying exact size. For a lot of folks, the 50cm^2 SD / under 73mm diameter of any of the MA 7/70 series cones would certainly put them in that general category - until they heard them in the right box 😀.

Yeah, I've long been a fan of each of the bassists involved - but had never heard of this particular collaboration, so it was a very pleasant surprise. You might think these guys would be ego tripping over each other - not on the couple of tracks I heard for sure "Tutu" which Marcus wrote for Miles' of that name was probably my favorite.

Forgot to mention they were driven by a pair of EL84 SE amps - one my early junkyard / salvage projects. Straight, no filters, no woofers.
 
#24
Referring to the organ 2 notes effect
I play the violin, and if you play two notes at once, (if they are perfectly in tune) an interference note is sounded. I have had my teacher play a series of these where the interference notes produced "God save the Queen"!
 
#25
No, those thunder discs were with the rather poor all in one sounding bose, which measure only down to 80hzwith a massive bass hump.
The soundlink mini is a different league. Play tracks like dave brubeck take five and the sound is quite awesome. I'm still wondering how the measured response (rew) manages to pussh 55hz. There are 2 passive radiators measuring approx 3inch x 2 inch and look to have quite a bit of mass on them. Even with dsp the physical size dictates the bass depth and output should not be possible. The bass is quite literally musical.
Go for a demo. I have never been a fan of bose, but the engineering that has been put in this one and only product of theirs needs to be listenef to.
Give me your opinions.
 
#26
tuxedocivic said:
Kevin, I didn't mean car audio bass. 75db isn't all that loud. But for dynamic (musical) bass, you need them to be big. It's that effortless/effecient bass that sounds good and low distortion. The little drivers are trying to hard. So I'd suggest that larger drivers have the edge in terms of "finesse" and "musicality" as you would like in a driver. Little drivers sound like they're trying way to hard.
😛
Click to expand...

I would argue the complete opposite and here's the complete argument:
What makes a note musical and identifies it? its the harmonics i.e. the waveform shape. A sinewave is the simplest note but it is the non sinewave that carries the musical information, ie the harmonics OK? Ever heard a 40 Hz sinewave and you will see (hear) what I mean its 'dead'.

So actually the reproduction of non sinewaves is a good indicator of musical accuracy is it not? Take a sqare wave, for instance (the most difficult). What would produce a square more accurately - your monster bass driver of a 4" good fullranger (assume it's one of the best)?

You might be wrong here - it's the fullranger. Your monster woofer will only ever ever give you a sinewave as it can't produce the upper harmonics and it is these that give the sharp leading edge (an infiite number of harmonics in theory).

So you combine the woofer with a teeter and it sounds sort of Ok (right frequency spectrum) but you still will never approach hat sqaure wave accuracy that the full ranger does - it's impossible. Don't forget its the wave-shape that defines the quality of music inthe first place. Actually a full-ranger will never do it perfectly eaither, but if it covers the audible range (in phase)you won't notice the diference.

Its the same with less extreme musical waveforms - the full-range is better at producing them accurately. Some people may not notice the difference but I can tell you others can, and that's the 'full-range magic. ' in scientific terms. By the time the signal has been split, passed through a crossover and shot through disparate drivers and shot around the room to the listener it is fundamentally changed and our 'musical' bass note is disorted, pure and simple (or not so pure!) 🙂

Acoustic Insight
 
#27
I'm pretty sure my headphones have a driver that is smaller than 3".
They give good bass response.
I would not expect realistic bass response when trying to drive a room load.

Smallness is not a deciding factor in bass extension capability.
Adequate SPL in relation to the other audio frequencies is very much a deciding factor in bass reproduction. That SPL capability is tied to driver SIZE.
 
#28
delphiplasma said:
No, those thunder discs were with the rather poor all in one sounding bose, which measure only down to 80hzwith a massive bass hump.
The soundlink mini is a different league. Play tracks like dave brubeck take five and the sound is quite awesome. I'm still wondering how the measured response (rew) manages to pussh 55hz. There are 2 passive radiators measuring approx 3inch x 2 inch and look to have quite a bit of mass on them. Even with dsp the physical size dictates the bass depth and output should not be possible. The bass is quite literally musical.
Go for a demo. I have never been a fan of bose, but the engineering that has been put in this one and only product of theirs needs to be listenef to.
Give me your opinions.
Click to expand...

Bose is not the first to do this - it was started by Jawbone with their Jamboxes and Jambox mini. The recipe is always the same: high excursion drivers with passive radiators. But efficiency is low - they are using quite a bit of power but that is easy with class D amps.

You can build a DIY version with a TB W3-1876 3 inch sub. It has 4 mm xmax, 55 Hz fs, 76 dB efficiency. In a vented 840 mL volume it will reach 52 Hz. Pair with the passive radiator and the volume can probably be cut in half. It's not that hard to make - it is just an engineering and packaging exercise.

Tang Band W3-1876S 3" Mini Subwoofer | 264-909
 
#29
Hmmmmm...I've heard the jambox...jawbox...etc and they don't seem to produce real deep bass and seem unbalanced. Hence I've not measured the frequency response.

True enough class d amps allow more power output with less power consumption. However, the drive units seem little stressed (minimal cone excursion) when producing bass.
 
#31
Kevin. All you did was position your opinion in the mid/high frequency ranges, which isn't the point/discussion. I even consented in my post that the smaller drivers do mid/highs better which is why my preference is 4" drivers. You've said this: small drivers make better bass because they make better mids/highs.

Sorry but when I'm evaluating bass, I'm actually evaluating bass.
 
#32
Hi bob,

I'm guessing this class d amp is probably only pushing out up to 10 watts. However, the bass manages to fill the room, so not just nearfield.

I have compared the bose to a pair of bookshelf kef speakers of approx 8litres bass reflex with 5inch bass unit and the bose manages deeper bass in both measurement and listening.
 
#33
Bose does not give techical spesification of Soundlink. It has a built-in accu, obviously d-class amplifier and perhaps even dsp sound equalization built-in, to give bass boost and extension. I can guess that the amp gives some max 40W power. Focus is in simple usability, only input and sound volume can be adjusted. Reviews tell it sounds wonderful, with rich and deep bass for it's size. I have not heard it, but I believe it is a gem for 200$/€.

Guys discussing about 3 and 4" bass - please show us some measurements of distortion, tell measuring distance too!

Her is my measurement of Tangband 871-s in 2 liter closed box. Measured with Umik-1 and REW at ~1m. By the way there is huge rise in distortion from 75 to 80dB volume! 70dB at .5meters is too easy to give anything meaningful info!
 

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#34
tuxedocivic said:
Kevin. All you did was position your opinion in the mid/high frequency ranges, which isn't the point/discussion. I even consented in my post that the smaller drivers do mid/highs better which is why my preference is 4" drivers. You've said this: small drivers make better bass because they make better mids/highs.

Sorry but when I'm evaluating bass, I'm actually evaluating bass.
Click to expand...

Its the mid and highs that are an inseparable part of the bass (and give it a musical quality) - that is my point, unless you are talking about a pure sinewave. If you listen to a slamming bass the 'slam' part is the high frequency component. Ever tried 'slamming a sinewave'?
 
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#36
I'm not trying at all, its signal theory. Bass notes can't be evaluated fully without the full musical spectra - fact. Take a look at Bob's spectrum analysis. Signal theory dictates that a bass note is defined not only by its fundamental but the higher harmonics that consiute the waveshape. Any musical wave can be seen as the sum of component sinewaves combined correctly. Look it up! Ok there are other properties of bass such as volume envelope and you need to look at this as well. That's called transient response and/or maximum volume capability, usually measured with a pure sinewave without any harmonics. That is where some full range designs are sometimes considered to fall short. Actually all speaker systems will fall short, depending on your benchmark for realism. and what you want from the system.
 
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#39
The class d XLS series has a good reputation, except that the 1000 has a rather high noise floor. I got the 1500 for that reason alone, as I don't really need 1500w @ 2Ω. I have not been using it full-range, but it sounds very nice on the bottom. I have yet to have the cooling fan turn on.

Bob
 
#40
@tux

The very point I was making in post #1 is that the perceived nature of a bass note is contained in the harmonic. Otherwise, a 3" driver would sound like a table radio. Note that the harmonic structure of the string bass is still going strong above 1kHz.

Bob
 
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