Why the fascination with subwoofers?


I have noticed many posts with questions about adding subwoofers to an audio system. Why the fascination with subwoofers? I guess I understand why any audiophile would want to hear more tight bass in their audio system, but why add a subwoofer to an existing audio system when they don’t always perform well, are costly, and are difficult to integrate with the many varied speakers offered. Additionally, why wouldn’t any audiophile first choose a speaker with a well designed bass driver designed, engineered and BUILT INTO that same cabinet? If anyone’s speakers were not giving enough tight bass, why wouldn’t that person sell those speakers and buy a pair that does have tight bass?
2psyop
rauliruegas:
"Dear @noble100 : HT and stero MUSIC reproduction room/systems needs are different.

Maybe that’s why you are the only audiophile I know that can’t be aware of the difference using a high-pass filter in the stereo music main speakers and with out that filter even the wider frequency range in those bass drivers. Not only that but you said you preffers with out the high-pass filter because better bass quality performance."


Hello rauliruegas,

Why do you believe the reproduction requirements/needs of HT and stereo music are different?
I believe a single system that is able to reproduce the full 20-20,000 Hz frequency range accurately, with low distortion and proper dynamics is fully capable of reproducing both with high quality.
My combination stereo music and ht system is fully capable of reproducing the full range of audible frequencies with high accuracy, very low distortion and powerful dynamics and, therefore, performs with high overall quality for both stereo music and ht.
You also seem to have difficulty understanding why I didn’t notice a significant improvement in the performance of my Magnepan 2.7QRs main speakers when connected to the high pass filtered outputs on my sub amp rather than being run full range. I believe you need to understand the details of my system to understand why I prefer running my main speakers full range.
I built my system from the bass up because good bass response forms the solid foundation for most music and ht. Bass is also the most difficult portion of the frequency range to achieve high quality performance at in most home rooms due mainly to the extreme length of bass sound waves which are longer as the frequency decreases. For clarification, a 20 Hz deep bass full cycle soundwave is 56 feet long and a 20,000 Hz high treble full cycle soundwave is a fraction of an inch long.
The system solution I decided upon was to construct a separate high quality bass section for reproducing frequencies from 20-100 Hz, which is the frequency range of my 4 subs, and a separate high quality full range section for reproducing frequencies from 35-20,000 Hz, which is the frequency range of my main 2.7QR speakers, and blend the 2 sections together seamlessly by precise adjusting of the crossover frequency and relative volume settings of the bass section. I consider this system solution to have been a total success with the crossover set between 40 and 50 Hz and the sub amp relative volume set just under halfway at about 11 o’clock on the dial.
I’m not exactly sure why you notice such a big improvement in your system performance using hi-pass filtering while I don’t.
I use a crossover frequency of 40-50 Hz compared to your 80 Hz. Any sonic gains expected from the reduction on bass frequency amplification demands to above 40-50 Hz on my main speakers amps may not have been realized since my mono-block amps are not lacking in power with 1,200 watts into the speakers 4 ohm load, so there’s no lack of power from the bass to the treble. The sonic gains of your amps being relieved of bass amplification demands to above 80 Hz, however, seems to have been much better realized. Do you think more regular and reserve power being freed up for your speakers midrange and treble drivers could be the reason you notice improved performance in those frequencies?
Another possible explanation of why I don’t prefer using the hi-pass filters in my sub amp could be the Magnepan 2.7QR main speakers I use as mains. These are 3-way planar panels that have rather large 620 square inch bass sections which provide very high quality bass on their own but that lack deep bass impact and dynamics. Perhaps the improved bass response I noticed with running the mains full range is a result of the very high quality and articulate bass of my mains combined with the increased impact and dynamics provided by the AK Debra DBA system. I’m unsure of how well the bass quality of your ADS speakers run full range would combine with the increased impact and dynamics provided by your Velodyne subs. Perhaps you can try it sometime and find out.

Tim
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Excerpt from the OP:
I guess I understand why any audiophile would want to hear more tight bass in their audio system, but why add a subwoofer to an existing audio system when they don’t always perform well, are costly, and are difficult to integrate with the many varied speakers offered. Additionally, why wouldn’t any audiophile first choose a speaker with a well designed bass driver designed, engineered and BUILT INTO that same cabinet? If anyone’s speakers were not giving enough tight bass, why wouldn’t that person sell those speakers and buy a pair that does have tight bass?

... but why add a subwoofer to an existing audio system when they don’t always perform well, are costly, and are difficult to integrate with the many varied speakers offered.
Almost always the objection--"poor performance, costly, and difficult to integrate."

"poor performance" When it comes to sub 100Hz frequencies, the powered subs outperform most "full range" speakers. 

If you check the response curves of most "full range" speakers, their frequency responses start dropping off at around 100 Hz. Sometimes you can compensate with good room reinforcement, but if you're on a wooden suspended floor, forget it.

"difficult to integrate..." Not if you use powered subs with the right controls. My two subs have controls for volume, crossover, and (most importantly for integration) phase. A 2-way 180 deg. toggle won't cut it. Mine have 0-180 deg. phase controls. The controls are continuous with no notches nore 2- or 3-position toggles. The volume integrates the subs' outputs with the mains, and the crossovers match the LF dropoff curves of the mains without a hump or dip where the subs pick up the lower frequency curve.

It takes me about 2-3 hours to integrate subs with my stereo, more likely 1-2 hours. For phase I use a mono recording to adjust each channel separately and make sure the channels' phase blends seamlessly with the mains.

For a final check I use the Stereophile test & demo CD, and listen to the bass frequency samples that drop from around 150-200 Hz on down to about 20 Hz. I generally get a linear dropoff down to around 36 Hz, which is a good match for my Magneplanar 1.7s, which are fantastic in the 80-20K hz range but missing in action below 80 Hz.

"...are costly,..." If you want full range reproduction, powered subs can be a stone cold bargain. Consider the true full range loudspeakers such as Wilson XLF and top line Magico. They are hundreds of thousands of dollars. Now consider a pair of KEF LS50s at $1300. Yeah, their LF limit is 80 Hz, but from that point on up to 28Khz they are Stereophile Class A loudspeakers, all for $1300. Add JL Audio Dominion D110 sub for another $1050 (or two for $2100) and you have a full range S-phile-rated Class A pair of speakers (with anechoic bass extension to 27 Hz) for $2450 to $3400, which is far, far less money than full range floorstanders that could match the KEFs in speed, image, linearity, clarity, and bass integration.

Remember that with full range speakers, the massive deep bass backwaves create a turbulent tempest in the enclosure's interior, interrupting the cone movements of the midranges and possibly the tweeters as well. Powered subs keep all that bass backwave drama in a tight box separated from the mains.
So from my perspective, quality powered subs increase performance, enhance clarity, make room placement easier, *AND* save money.

A lot of the cost of full-range floorstanding speakers goes to the herculanean efforts to keep the cabinet panels and braces from vibrating. Exhibit A: WIlson XLF or whatever has followed.

I use 4 subs but I have floor to ceiling linear arrays and two subs just won't make it. If you are clever and work with your room acoustics and you have a point source system which is just about all of you, 2 subs will work perfectly fine. In most normally sized houses I do not see the need for drivers over 12".  I think 12" is perfect. In addition to a properly designed driver the key to sub performance is a very heavy solid enclosure. Any vibration of the enclosure is distortion. If you put your hand on the enclosure at volume and you feel it buzzing away you have a problem. The best enclosures do not resonate at all and you do not have to do anything to them. If your enclosure vibrates the first thing to do is go to the local granite store and you can usually get cut offs for cheap. Just place an appropriately sized piece right on top of the sub. That can help tighten things up quite a bit. Also make sure the sub has 3 spiked feet not four. Three feet make a much better connection to the floor. No rocking. Subs have to be right up against a wall or in a corner. They are 3 to 9 db more efficient this way.
Some people are after All the response , not just down to what their neighbours are ok with. If i had two speakers that incorporated the subs involved they would weigh 250 pounds each . A four way system tri amped is far and few between and i dont think manufacturers are willing to sit on them hoping someone will buy them before some fancy pants gives them a thumbs down. Everything is a seasoned to taste affair . Pick your components and turn your obtainable mains into monsters for a much more realistic concert experience. Or bump them up a little bit in low listening levels to make the sound fuller .