Woofer question: One big versus several small?

[AEIOU]

fast bass from yamaha.

fast bass boat - youtube

lol

[djg]

Fast bass from Yamaha.

Fast Bass Boat - YouTube

[charlielaub]

I find it pretty sad that people are still caught up in this "fast vs slow bass" nonsense. I have read how people go out of their way to look for low Mms subwoofers, thinking that the lower mass will be "faster" and that 'faster sound" will be... better??? As if this is the only parameter that matters...

These folks don't seem to have a clue about the time-domain transient/impulse response, how it is related to the frequency response, and how it changes when the driver is band limited by a low pass crossover.

[billfitzmaurice]

Slow bass of a bass guitar vs fast bass of a stand up bass is analogous to the slow bass of a long excursion woofer that achieves the same note via excursion vs the fast bass of a low excursion woofer that achieves the same note via size.

Being both a speaker designer and bass player, electric and standup, I can say that there's no such thing as 'fast' or 'slow' bass. The main difference in electric versus acoustic is that the tone and timbre of electric comes primarily from the amp and speakers, that of acoustic from the instrument. The size of the body of the acoustic is simply too small to support anything approaching flat response to even the second harmonic, let alone the fundamental. This results in accentuation of the mids and highs compared to electric bass, and that's what those who don't actually know what's happening call 'fast' bass. Test side by side an acoustic and an electric standup bass, the latter in the form of an Ampeg (the instrument, not the amp), and an electric bass. The acoustic bass will sound thin in the lows, prominent in the mids. The Ampeg and electric will sound similar in the lows. The Ampeg will have a different midrange timbre, but a fretless electric will duplicate that.

[Unbiasedsound]

Mounting biggest subwoofer in the world (32") on car roof - YouTube

Damn djg you looked younger then I imagined. LMAO

[djg]

Mounting biggest subwoofer in the world (32") on car roof - YouTube

[fpitas]

I think it's a case-by-case basis whether multiple smaller woofers of the same effective cone area can effectively replace a larger woofer. I needed a 15" driver to go below a 511 horn, but the drivers I saw that would be appropriate, going smoothly to the 800Hz crossover, and up to 1.6kHz without crazy peaks etc were expensive, starting at $300 or so. I ended up using four 8" 830869 Peerless drivers. Same cone area as a 15, but the overall price was lower. It's true the Xmax isn't what a typical subwoofer driver would give, but the pro drivers we considered didn't have a large Xmax either. The 8s were placed in a square pattern below the horn to give a similar polar pattern as a 15. Using the 8s allowed us to angle the front baffles, each vertical pair of 8s angling outwards about 14 degrees to help with baffle diffraction. The cabinet is tuned to 28Hz, so deep bass for music isn't much of a problem. So far everybody who has heard the system is impressed.

[windcrest77]

To recap my analogy of small and large woofers to bass guitar and stand up bass strings...

String length of the bass instrument is analogous to the speaker diameter (short string = small speaker and long string = big speaker)

String tension of the bass instrument is analogous to the speaker excursion (low-tension string = high excursion speaker and high tension string = low excursion speaker)

The needed plucking force of the bass player is analogous to the watts you need to run the speaker (hard plucking of a loose string is needed to get the same power of soft plucking of a tight string = high watts to move long excursion vs low watts to move low excursion speaker). Additionally the stand-up bass has a "cabinet" so it needs no electricity. The bass guitar has no cabinet, it is a slab of lumber. The stand up bass is a big resonant cabinet.

Slow bass of a bass guitar vs fast bass of a stand up bass is analogous to the slow bass of a long excursion woofer that achieves the same note via excursion vs the fast bass of a low excursion woofer that achieves the same note via size.

[windcrest77]

too much time to think---

Has anyone listened to similar enough designs to decide if there's a noticeable difference?

For example, nine 4" drivers or four 6" drivers would have same area as one 12". If all the drivers had similar properties would there be a difference?

Would multiple smaller similar drivers have a higher total cost?

Would the narrower baffle have an advantage?

I cant give you a technically reasoned answer. But I can give you my cheap *** opinion after having attended Axpona this year and auditioned 100 or so systems. In a nutshell my wife and I preferred the sound of single large woofer systems 12 or 15 inch. Some were horn loaded, some bass reflex, none that I can remember were in sealed enclosures. Often times they were paired with horn loaded mid/high. Small or multi woofer dome tweeter System after system started to sound the same, too perfect, too clinical, with little apparent differences even at $20,000 price differential. The big boxes were just plain fun, especially on jazz with horns and stand up basses, Ella Fitzgerald, frank Sinatra, count Basie big band recordings from the 50's. Hearing the great baritone Joe Williams and the count Basie band we looked at each other and smiled. My wife and I are both dancers so we hear a couple live dance bands per week, big bands, small bands, all jazz related, often stand up bass, occasionally a slower bass like bass guitar (IOW bass with no attack) bass guitars don't swing too good. Some of our band even use a tuba player for the bass, 1920's Charleston bands. I trust my wife's ears, she isn't thinking of technicalities. After Axpona I visited here with my first post asking about doing a 15 inch system with horns and sensitive enough to hear the noise floor of my tube amps! I have a great deal of respect for folks here working all the math and voodoo, I'm not anti intellectual, a good large woofer speaker still needs that background. But this is just an empirical opinion.

[windcrest77]

too much time to think---

Has anyone listened to similar enough designs to decide if there's a noticeable difference?

For example, nine 4" drivers or four 6" drivers would have same area as one 12". If all the drivers had similar properties would there be a difference?

Would multiple smaller similar drivers have a higher total cost?

Would the narrower baffle have an advantage?

I cant give you a technically reasoned answer. But I can give you my cheap *** opinion after having attended Axpona this year and auditioned 100 or so systems. In a nutshell my wife and I preferred the sound of single large woofer systems 12 or 15 inch. Some were horn loaded, some bass reflex, none that I can remember were in sealed enclosures. Often times they were paired with horn loaded mid/high. Small or multi woofer dome tweeter System after system started to sound the same, too perfect, too clinical, with little apparent differences even at $20,000 price differential. The big boxes were just plain fun, especially on jazz with horns and stand up basses, Ella Fitzgerald, frank Sinatra, count Basie big band recordings from the 50's. Hearing the great baritone Joe Williams and the count Basie band we looked at each other and smiled. My wife and I are both dancers so we hear a couple live dance bands per week, big bands, small bands, all jazz related, often stand up bass, occasionally a slower bass like bass guitar (IOW bass with no attack) bass guitars don't swing too good. Some of our band even use a tuba player for the bass, 1920's Charleston bands. I trust my wife's ears, she isn't thinking of technicalities. After Axpona I visited here with my first post asking about doing a 15 inch system with horns and sensitive enough to hear the noise floor of my tube amps! I have a great deal of respect for folks here working all the math and voodoo, I'm not anti intellectual, a good large woofer speaker still needs that background. But this is just an empirical opinion.


as others have said large woofers simply "go lower" and have low-side headroom (foot room?). It's like if you compare the bass of a bass guitar where the plucked string is less that 3 feet long to the string of a stand up bass where the string is 6 feet long. For the 3 foot string to produce a low note it must be very loose, whereas the 6 foot long string can still be wound tight. Plucking the short string will still produce the note, but there will be no "attack" to the note because of such a loose string. It will be "slow bass". Whereas a 6.5 foot tall stand up bass when plucking that long tight string will produce an "attack" to the note that is exponentially louder than the 3 foot string on the guitar can ever produce. Musically this is what gives jazz "swing", the fast attack and decay of the bass with a 6 foot long very tight string. Large woofers can be "tight" with low excursion like the 6 foot string of a stand up bass. Small woofers need to be "loose" with high excursion to get the same note, like the short string of a bass guitar must be loose. So small woofers have "slow attack" in the bass, like a bass guitar has slow attack because it has such a short loose string, the compromise is to loosen the string a lot to achieve the same note. The compromise with a small woofer is to give it large excursion, but then it loses its attack to reproduce the same note as the large woofer which needs very little excursion, like a long but tight stand up bass string.

[bradley.s]

Multiple small speakers with wide bandwidth can also be arranged in a manner that produces a desired dispersion characteristic, such as a column or line array.

Specifically with regard to my personal motivation for DIY, I think this overcomes the value proposition of large vs multiple small explained earlier in the post. If I was motivated to make beautiful speaker cabinets I'd lean toward larger woofers.

That was a good post to help someone design and achieve their goals.

[billfitzmaurice]

I'm not quite sure how in your single mindedness you seemed to miss the fact that larger woofers do reach significantly lower

I'm not quite sure how in your singlemindedness to disagree with me you seem to miss the fact that I said I use larger woofers, in subwoofers where they belong.

[AEIOU]

F3 (how low a speaker will reach) is not determined by Fs alone, it's determined by Fs and Qts. A large woofer w/an Fs of 20Hz (and a Qts around 0.40) CAN reach 20Hz (in a vented box), but so can 8" or 7" or 6-1/2" woofers w/an Fs of 30 or 40Hz (IF they also have Qts values in the 0.50 to 0.60 range).

And in the real world. . . .

[Chris Roemer]

F3 (how low a speaker will reach) is not determined by Fs alone, it's determined by Fs and Qts. A large woofer w/an Fs of 20Hz (and a Qts around 0.40) CAN reach 20Hz (in a vented box), but so can 8" or 7" or 6-1/2" woofers w/an Fs of 30 or 40Hz (IF they also have Qts values in the 0.50 to 0.60 range).

[AEIOU]

That's not actually the case. Since sensitivity goes up by 6dB/volt with each doubling of driver count the opposite can be true. But the no free lunch rule applies, the driver cost will usually be higher with multiple drivers, and that's why they don't own the marketplace. As for the lack of large driver 3 ways, that's the result of using 2 way mains with 1 way subs. It's still a 3 way system, contained in more than one box. Since that offers the option to place the low frequency sources and higher frequency sources where each works best, which is almost never within the same footprint, it's by and large a better way to go.

I'm not quite sure how in your single mindedness you seemed to miss the fact that larger woofers do reach significantly lower, simply because the have a much lower fs and the voice coil to do the deed. No problem finding a 15" woofer or even a 12" woofer that has an fs in the 20s. Try that with a 6.5" woofer! If you do have a 6.5" woofer that has an fs as low as the big boys, it will have such a heavy cone which makes it very inefficient. You struck out on this one Bill.