# How does Bose create small speakers which produce powerful sound?

#### SeekingProtection

##### Member
How does Bose create small speakers which produce powerful sound? Other speaker companies seem to require big drivers produce the same quality of sound but Bose uses only 2 inch drivers. How does it achieve such powerful sound with them? All of it cannot be due to DSP, is it because of amplifiers they use, which makes the drivers move with more velocity? Is it the tuning?

Would it be possible for me to build such system myself? And will it run afoul of Bose's patents? Where can I buy such equipment to build such speakers myself?

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#### Nigel Goodwin

##### Super Moderator
Bose use sub-woofers to give the powerful bass sound, the small speakers are only for the high frequencies.

You should also know that Bose are very poorly rated by anyone involved in audio or HiFi, it's very over priced equipment, with an inaccurate sound reproduction - aimed at people with more money than sense (fashion more than quality).

#### SeekingProtection

##### Member
Yes I know Bose speakers are frowned upon by audiophile community.

But these other audiophile speaker companies like Bowers & Wilkins, they also pair their satellites with sub-woofers, and qualitatively they don't sound any different than Bose speakers. So how much does speaker ratings matter? Humans when they hear, their ears don't measure off-axis and on-axis, if the track is +/- 3dB louder or quieter than the original recording, because as they are hearing, they can't measure the speaker's reproduction of a track against how the real track would sound.

Besides there are many audiophile companies which have the same speaker ratings, but different users prefer different speakers, one cannot ignore the subjective aspect of speakers.

#### gophert

##### Well-Known Member
Yes I know Bose speakers are frowned upon by audiophile community.

But these other audiophile speaker companies like Bowers & Wilkins, they also pair their satellites with sub-woofers, and qualitatively they don't sound any different than Bose speakers. So how much does speaker ratings matter? Humans when they hear, their ears don't measure off-axis and on-axis, if the track is +/- 3dB louder or quieter than the original recording, because as they are hearing, they can't measure the speaker's reproduction of a track against how the real track would sound.

Besides there are many audiophile companies which have the same speaker ratings, but different users prefer different speakers, one cannot ignore the subjective aspect of speakers.
The "right Sound" is whatever you get used to. My favorite versions of some classic songs are the ones I remember hearing in my '74 pinto with Jensen speakers and the stock am/fm cassette. Listening to the same songs on a friend's expensive Fisher home audio system seemed a bit "off". If you are happy with a particular receiver/speaker/room/price combination, don't let anyone else tell you to be unhappy.

#### Externet

##### Active Member
At least in the past, a way Bose made more powerful speakers was by their voice coil being in the neighborhood of 1 ohm impedance instead of the typical 8.

#### crutschow

##### Well-Known Member
Generally the Bose system has a frequency dip between the low end of the small speakers, and the high end of the subwoofer.
It may not be noticeable when using it for TV and home theater sound, but it is usually noticeable with music.
If you think "other audiophile speaker companies like Bowers & Wilkins, they also pair their satellites with sub-woofers, and qualitatively they don't sound any different than Bose speakers" then you have never compared them side by side.

One way to somewhat compensate for the small speaker is to to use an active filter or DSP to increase the gain at the small speaker's low frequency end to compensate for it's drop-off.
But that's limited by the small speakers ability to move more air for equal volume before it distorts, which is required as the frequency drops.
So what you would need is speaker that is defined as a full range that can generate a large cone excursion such as shown:
(Note the rolled speaker surround, that allows a long excursion.)

Along with that you need an amp with a good amount of undistorted power available.
But there still a limit to the maximum that a 2" speaker can do at lower frequencies.
There's no other magic or "tuning" that can help
That's why other speaker manufacturers use larger speakers.
At least in the past, a way Bose made more powerful speakers was by their voice coil being in the neighborhood of 1 ohm impedance instead of the typical 8.
That makes the speaker easier to drive at a high power level with a given supply voltage, but it doesn't increase the maximum output the speaker can deliver.

#### SeekingProtection

##### Member
The "right Sound" is whatever you get used to. My favorite versions of some classic songs are the ones I remember hearing in my '74 pinto with Jensen speakers and the stock am/fm cassette. Listening to the same songs on a friend's expensive Fisher home audio system seemed a bit "off". If you are happy with a particular receiver/speaker/room/price combination, don't let anyone else tell you to be unhappy.
I don't have any high-end speakers, not even Bose. But I listened to Bose speakers at the store, I liked the bass on it, it had a kind of premium feel to, like the experience you get when you step into the sound booth or theater. But they were expensive, so I thought maybe I could build something similar cheaper.

I have similar experience as your Jensen-Fisher speakers experience, but mine was with a cheap speaker, I don't remember the brand, on this cheap speaker the song sounded nice, well rounded, when I heard the same track on an expensive speaker, I think it was an Elac, the song sounded very bland, like there was static. I thought there was something wrong with the expensive speaker but the person who demoed it said there was nothing wrong with it. It almost felt like, people who were spending money on the expensive speaker were not getting their money's worth.

I have a similar experience with in-earphones, my friends $199 earphones sounded bland but a$30 earphones sounded so good, I still don't understand what would one get with a $199 earphones, do they hear more sounds or will those sounds sound better than$30?

At least in the past, a way Bose made more powerful speakers was by their voice coil being in the neighborhood of 1 ohm impedance instead of the typical 8.
I didn't know that, is that efficient even now?

Generally the Bose system has a frequency dip between the low end of the small speakers, and the high end of the subwoofer.
It may not be noticeable when using it for TV and home theater sound, but it is usually noticeable with music.
If you think "other audiophile speaker companies like Bowers & Wilkins, they also pair their satellites with sub-woofers, and qualitatively they don't sound any different than Bose speakers" then you have never compared them side by side.
That's true, I didn't hear them side-by-side, and I don't know where I can hear them side-by-side. But from my memory they seemed to have sounded very similar.

One way to somewhat compensate for the small speaker is to to use an active filter or DSP to increase the gain at the small speaker's low frequency end to compensate for it's drop-off.
But that's limited by the small speakers ability to move more air for equal volume before it distorts, which is required as the frequency drops.
So what you would need is speaker that is defined as a full range that can generate a large cone excursion such as shown:
View attachment 117913 (Note the rolled speaker surround, that allows a long excursion.)

Along with that you need an amp with a good amount of undistorted power available.
But there still a limit to the maximum that a 2" speaker can do at lower frequencies.
There's no other magic or "tuning" that can help
That's why other speaker manufacturers use larger speakers.
That makes the speaker easier to drive at a high power level with a given supply voltage, but it doesn't increase the maximum output the speaker can deliver.
Thanks for this valuable information. The Bose calls their sub-woofers, acoustimass modules, they seem to incorporate a kind of cylinder inside their structure, to prevent the bass from directly interacting with the room. I don't know how it works, the bass seems to first interact inside the cylinder and that is heard or allowed into the room.

What would be best cross-over for satellites and this type of sub-woofer? How would I build the cylinder inside the sub-woofer?

#### Nigel Goodwin

##### Super Moderator
But these other audiophile speaker companies like Bowers & Wilkins, they also pair their satellites with sub-woofers, and qualitatively they don't sound any different than Bose speakers.
They sound totally different, better speakers sound much more realistic, Bose are inaccurate and designed to sound artificial.

#### Nigel Goodwin

##### Super Moderator
What would be best cross-over for satellites and this type of sub-woofer? How would I build the cylinder inside the sub-woofer?
I presume you mean a 'port'?, this is common on many speakers - and is tuned to the particular cabinet and driver used - and not just in sub-woofers. It increases the bass response, but means it drops off faster below that point, and also decreases the power handling of the speaker. It doesn't have to be a tube, a hole is common, as are folded ports - speaker cabinet design is a very complicated subject.

#### SeekingProtection

##### Member
I presume you mean a 'port'?, this is common on many speakers - and is tuned to the particular cabinet and driver used - and not just in sub-woofers. It increases the bass response, but means it drops off faster below that point, and also decreases the power handling of the speaker. It doesn't have to be a tube, a hole is common, as are folded ports - speaker cabinet design is a very complicated subject.
No, not the port. There seems to be a separate chamber inside their sub-woofer, the bass seems to first interact inside this chamber before the room.

#### nsaspook

##### Well-Known Member

No highs, no lows, must be Bose!

#### Nigel Goodwin

##### Super Moderator
No, not the port. There seems to be a separate chamber inside their sub-woofer, the bass seems to be first interact inside this chamber before the room.
Looks like a port, or two ports.

#### crutschow

##### Well-Known Member
The Bose calls their sub-woofers, acoustimass modules, they seem to incorporate a kind of cylinder inside their structure,
Yes, Bose is good at putting catchy names on a more-or-less standard design. Bose has managed to market their systems so people think they are high-end, when they are not.

Their subwoofer has a tube connected to the back of the speaker. It reverses the phase of the sound-wave from the back of the subwoofer speaker so that it reinforces the sound from the front of the speaker.
It's length is such that it has a resonant frequency at the desired bass frequency.
It increases the volume of the bass significantly at this resonant frequency, but can cause a peak in the bass response at that frequency, which makes the bass sound boomy and one-note, with poor transient response.
If you notice, all the bass notes from the Bose tend to sound very similar -- okay for movie special effects, but not good for music..
The tube has nothing to do with reducing room interaction.
What would be best cross-over for satellites and this type of sub-woofer? How would I build the cylinder inside the sub-woofer?
The cross-over is determined by the low-end frequency response of the satellite speakers. Ideally the low-pass roll-off of the satellite coincides with the high-pass rolloff of the subwoofer so that the total output has no dips or peaks in the summed response at the crossover.

Look up bass-reflex subwoofer design with a tube port for more info on building a similar design.
There are many references on-line about that.

#### audioguru

##### Well-Known Member
I was at a Bose demo at an audio show and they had two large speakers producing very deep lows and a flat frequency response up to above audio frequencies. Then two pretty girls removed the large fake covers over little speakers that were actually producing that wonderful sound. I couldn't believe it because I looked around and I did not see the sub-woofer that must have been well hidden.

Today I looked at Bose Acoustimass in Google and looked the technical spec's of their expensive new system. Weight, sizes of the cabinets and price. No frequency response, no distortion amount and no output power amount. On YouTube a person dismantled a system and showed its small 2.5" satellite speakers and the little 5.25" car door speaker used as a "subwoofer".

#### audioguru

##### Well-Known Member
I forgot to say that I saw a very little portable Bose speaker at a Costco demo. It produced fairly deep and powerful bass. It costs a fortune.

#### ronsimpson

##### Well-Known Member
Note the rolled speaker surround, that allows a long excursion
The ability of a speaker to move air is a function of its volume. The area of a circle is (A = π r²). The third dimension is the "through" or travel of the speaker. (in/out) I had some 20" speakers with little travel. A 10 inch speaker needs to have 4x more travel to move the same air. A little 5 inch speaker will need to have 16x the travel. For a little speaker to act like a big speaker the magnet must be designed to move the cone a long distance. That is why many small speakers have very long (big) magnets.

#### SeekingProtection

##### Member
I forgot to say that I saw a very little portable Bose speaker at a Costco demo. It produced fairly deep and powerful bass. It costs a fortune.
By your user ID, I'm guessing you'd have pretty good knowledge about audio. Tell us, was the bass one-note, as crutschow says?

Do you think Bose speakers are still flat sounding? It must have been a long time, as they are no longer doing that show of hiding small speakers in a large box and revealing them at the end of the demo.

How important are the technical details in speakers? Bose doesn't publish them but people seem to think they sound great, but audiophiles say they are ignorant consumers.

#### Nigel Goodwin

##### Super Moderator
How important are the technical details in speakers? Bose doesn't publish them but people seem to think they sound great, but audiophiles say they are ignorant consumers.
Only people with low expectations, and no desire for accurate sound reproduction, think Bose sound great - if that's all you're after, then buy some Bose gear, you're unlikely to find any designs on-line done so badly as to sound like Bose.

#### gophert

##### Well-Known Member
How important are the technical details in speakers?
Important enough that a manufacturer will show them EVERY TIME when they are good. So, statistically, the correlation of Published data to speaker quality is pretty good. Conversely, the lack of data means the marketing department is hiding the data and spinning the quality by simply using words like "exceptional", "room-filling", "realistic", ...

Also, the best way to compare sound is to hear two samples back-to-back. Bose prevented that by only allowing customers to compare non-Bose systems to Bose systems by putting their demo speakers in "Bose listening rooms" at major retailers or Bose stores.

Notice that the Bose name doesn't bring the bling that it used to. No more Bose stores*, no more Bose listening rooms at Best Buy, and (most importantly), the factory-installed Bose systems on new cars used to be top-level Lexus, Cadillac, Infinity. Now Bose is in mid-trim level Mazda, Nissan, Chevrolet, and Buick with Harman Kardon and other brands in the top trim level models.

Good luck finding your sound system.

*Note: only a handful of Bose Stores still exist in a few outlet malls. Now Bose systems are available at Target, Kohl's and Amazon - not my first stop for high-end audio.

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