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Thread: Subwoofer or No Subwoofer?...That is the Question.

  1. #31
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    Quote Originally Posted by Storm View Post
    So, you guys are saying better to sell the subwoofer?
    I have this sub in my system right now, but will take it out and put in on eBay within a couple days.
    -Storm.
    Take any audio related internet advice with a huge grain of salt. A lot of advice is treated as being universal when it isn't. A good percentage is also out right wrong and only used to sell you more audio products.

    I think its best to come up with your own ideals about what your system should sound like. The hard part is knowing what to change to get it there. Just buying products that are "better" is counter productive.

    Personally I wouldn't live with Valencias because they don't match what I want my system to sound like. I don't like the lean bass and quite a few other things they do. But I learned from the speakers I"ve tried which helps to know what to change to reach the sound I want.(hopefully!) It helps cut through the propaganda and the things that don't apply to me or my room.

  2. #32
    Senior Member Storm's Avatar
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    Shane -

    What speakers do you use?

    Why don't you like the Valencias?

    -Storm.

  3. #33
    Administrator Robh3606's Avatar
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    Hello Storm

    Before you banish it to E-Bay how steep are your crossover slopes??? I had a similar problem with my subs and my mains. I was getting more room gain and LF extension than I thought I would from my mains and the only way to not have a bass peak using the rolloff from the box tuning and the 12Db slope in the sub network was to cut in the sub too low. I ended up using 24Db slopes on both sides. Then it worked fine. Don't know if you want to consider this or not.

    Rob

  4. #34
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    Quote Originally Posted by Robh3606 View Post
    Hello Storm

    Before you banish it to E-Bay how steep are your crossover slopes??? I had a similar problem with my subs and my mains. I was getting more room gain and LF extension than I thought I would from my mains and the only way to not have a bass peak using the rolloff from the box tuning and the 12Db slope in the sub network was to cut in the sub too low. I ended up using 24Db slopes on both sides. Then it worked fine. Don't know if you want to consider this or not.

    Rob
    I have had similar issues too. Why don't you keep the sub for a while and experiment a bit? Placement location heavily influences sub performance too.

    Did you cut-off the low frequecies to your Altec system and match the freq. to your sub?

    Lots of stuff to think about....it's all part of the fun.

  5. #35
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    I have found that a sub-woofer is not only useful simply in the reproduction of very low frequency musical tones. They can reproduce the ambient acoustic sound or feel of a room that may exist on a recording. For example, The Trinity Sessions by the Cowboy Junkies, which was recorded in the Church of the Holy Trinity in Toronto, Canada, with a Calrec Ambisonic microphone. When the song Mining For Gold begins, there is silence, yet you can hear and feel the venue, the space or the atmosphere within the church, almost a shuddering movement of air reaching up from the sub-sonic. The woofers are pumping away madly yet there are no instruments playing, and this is on a CD, not a record and turntables "woofer warble". The song is sung acapella by a woman so the sub is not reproducing voice or instruments. Turning off the sub removes the realism of the space that was captured on this recording. There are many recordings that have similarly captured this room acoustic sound or feel that I believe is only revealed with a good sub-woofer or other specialized low frequency speaker system.

    A sub may also be deemed necessary due to the human ears low sensitivity to low frequency tones. We cannot hear these frequencies until a certain SPL threshold is crossed. Look at the classic Fletcher-Munson "equal-loudness contours":

    http://en.wikipedia.org/wiki/Fletcher-Munson_curves

    Note that the threshold of audibility of a 20Hz tone is far above that of tones at 100Hz and above. This is why a four inch "woofer" can be said to reproduce 20Hz but is otherwise inaudible. On Strauss' Also Sprach Zarathustra, made famous in the move 2001: A Space Odessey, the Opening contains some very low rumblings before the horns begin that can be completely missed because they are both low in frequency and level. Other than large horn loaded woofers, sub-woofers may be capable of producing the acoustic output necessary to make these sounds clearly audible. A typical 12" 3-way speaker is not capable of doing this. Of course a sub-woofer can be over used and ruin ones music, but I don't feel they should be dismissed as useless for that reason alone. Whether or not they are necessary may be subjective, but I feel they are very useful when used appropriately. In the Home Theatre environment, let's remember that a sub is connected to the LFE, Low Frequency Effects channel, not an ultra low bass music channel. Booming and thumping is the name of the game under those circumstances. To me, apples and oranges.

  6. #36
    Dis Member mikebake's Avatar
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    Quote Originally Posted by Storm View Post
    The subwoofer more often than not puts out too much bass

    -Storm.
    I don't understand; you can't turn this sub down until the level is correct?

  7. #37
    Dis Member mikebake's Avatar
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    Quote Originally Posted by coherent_guy View Post
    I have found that a sub-woofer is not only useful simply in the reproduction of very low frequency musical tones. They can reproduce the ambient acoustic sound or feel of a room that may exist on a recording. For example, The Trinity Sessions by the Cowboy Junkies, which was recorded in the Church of the Holy Trinity in Toronto, Canada, with a Calrec Ambisonic microphone. When the song Mining For Gold begins, there is silence, yet you can hear and feel the venue, the space or the atmosphere within the church, almost a shuddering movement of air reaching up from the sub-sonic. The woofers are pumping away madly yet there are no instruments playing, and this is on a CD, not a record and turntables "woofer warble". The song is sung acapella by a woman so the sub is not reproducing voice or instruments. Turning off the sub removes the realism of the space that was captured on this recording. There are many recordings that have similarly captured this room acoustic sound or feel that I believe is only revealed with a good sub-woofer or other specialized low frequency speaker system. .
    Good post; the effect you mention is definitely there. It would be interesting to know what the mic captured; could have been the ventilation system or a distant subway!!

  8. #38
    Senior Member Steve Schell's Avatar
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    I agree with coherent_guy's coherent comments on all points. There is extreme low frequency contant in many (perhaps most) recordings that are most often not reproduced. Even on a simple recording like solo guitar there will be subsonic effects that add greatly to relism if reproduced well. It can be humorous sometimes, as a system with true low frequency extension will reveal artifacts (motor noises, subways, etc.) that the recording and mastering engineers likely never heard while monitoring on bandwidth limited systems like 604s.

    The modern trend toward extended lows in home theatre has given subwoofers a bad reputation, as most subs flail small direct radiators through wild excursions, generating high distortion percentages. This distortion along with the tendency to run them too loud causes the sub to draw attention to itself and muddy up the sound- yuck.

    Well designed horn subwoofers can deliver high SPLs and effortless dynamic swings with very low distortion; the tradeoff is that they are very large. The 15Hz. exponential flare subs I have built offer 108dB sensitivity from 20 to 80Hz. from a single 15" driver, but have volumes of 100 to 128 cubic feet. I recently discovered an equation by Frank Massa that allows the calculation of cone motion of a horn driver at a given frequency and output. According to this equation, my sub should be able to produce an acoustic watt (loud!) at 20Hz. with .080" of peak to peak cone motion. I am currently using an Altec 515-16G driver which has a rated maximum excursion of .150", so this is well within its capabilities. This cone motion would produce barely a peep from a small driver direct radiator sub. Also, assuming an efficiency of about 25%, the horn sub will produce the acoustical watt with four watts of amplifier power.

    One other drawback of a horn sub like this is the path length, which produces a 15 millisecond delay. This is clearly audible on transient material, and needs to be corrected by applying a delay to the rest of the system. Mother Nature doesn't make things easy!

  9. #39
    Senior Member Hoerninger's Avatar
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    Quote Originally Posted by Steve Schell View Post
    ... the tradeoff is that they are very large.

    ... One other drawback of a horn sub like this is the path length, which produces a 15 millisecond delay.

    This is clearly audible on transient material, and needs to be corrected by applying a delay to the rest of the system.
    When building such a horn, money and place is probably not much an issue. If you choose four instead of one 15 inch woofers, you can reduce horn length. The big horn can be devided into four parts, which makes them easier to handle.

    In Paragon XXL I choose two 15 inch speakers per side.
    ___________
    Peter

  10. #40
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    Steve

    Very interesting post. Would you say size and delay are the only challenges with a sub horn? (Assuming one had the money and technical resources to do it right.)

  11. #41
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    Well...

    . . . mikebake's point is well taken, there can be many extraneous sounds and other noises that comprise the background sounds in an environment. As Mr. Schell points out, some of that is pure garbage, is humorous at times, and apparently overlooked by the recording engineers (thanks for your comment Steve, I'd love to hear your horns, and it seems I almost could from where I am outside Chicago, given your accomplishments in the acoustic sensitivity and SPL areas!!) So much for the trend towards small studio monitors (and flailing subs!) Are you saying mikebake, that what I refer to is all acoustic garbage, and/or the effect does not exist? Regardless, a good sub has revealed things on albums I never heard previously, and I personally enjoy low bass. That may not be important to some, so be it.

    I've been wondering given all the new subwoofers out there, particularly ones with eight or ten (or less) inch drivers, if some breakthrough in driver technology occurred. Cone excursion has increased certainly, but as Mr. Schell points out, the only thing that really changed is our standards (well, some of us) on what is good sound and acceptable distortion levels. Subs get away with much by having their distortion harmonics rolled off outside of their tiny passbands. Or is much of a small subs output what is called "doubling"? Alas, horns are impractical deluxe (I think my first apartment was 128 cubic feet overall!) but I wonder what a large excursion driver flexing it's surround would produce in acoustic watts in a horn like Mr. Schell describes. It seems that horns remain impractical in many environments, certainly in the home, or are they just being overlooked?

  12. #42
    RIP 2021 SEAWOLF97's Avatar
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    Quote Originally Posted by coherent_guy View Post
    . . I think my first apartment was 128 cubic feet overall
    Hope you meant square feet, I can just see your stereo system in a 5x5x5=125cf foot place (does that include kitchen and bed ??) and that they were "nearfields"
    Some kind of happiness is measured out in miles

  13. #43
    Senior Member Steve Schell's Avatar
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    Hoerninger, multiplying the cone area and enlarging the throat is a practical way to shorten a horn and reduce the size and the length of delay in milliseconds. I am not convinced that the performance will be as good in terms of output level vs. distortion as the longer horn though, as the driver loading is reduced and the drivers are less shielded from loading variations from mouth and room reflections. My sub has a path length of 1/3 wavelength at 20Hz., which I regard as a minimum for really good performance. Having said that, I have heard 9' path horn subs using an 18" driver and 1:1 throat area that still sound very good.

    Titanium Dome, I can't think of any other challenges off hand, but the size and the delay are enough to give one pause (pun intended). The sound quickly sweeps one away and makes one forget the difficulties though. The way I have dealt with the size is to build the boxes narrow and tall, using the space up to the ceiling that is most often wasted anyway. My current sub has a footprint 29" by 93" and sits flat against the wall. It looks imposing but doesn't intrude on the room space too much, really.

    Coherent_guy, lean out your window and I'll crank the system up B^) . I certainly agree that extended low frequency response adds much to playback of good recordings. In the region where the energy is transitioning from that which is heard to that which is felt, the sensations are tactile and primal. Can't agree that narrow band subs have their distortion products filtered out, though. Their input is certainly band limited, but any distortion products generated by the device will be present in the output. Little Best Buy type subs often sound to me like their distortion products are louder than the fundamental.

    One tiny sub that actually seems to work pretty well is the little self-powered Carver cube. My partner Rich has one, and we have used it at two shows where the small demo room did not permit use of the big sub. It doesn't hold a candle to the horn sub on loud stuff, but doesn't embarrass itself either.

  14. #44
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    Busted

    Seawolf, I failed to mention my first "apartment" was in an upscale complex called Sunset Bay Dept. of Corrections, so the figure given was square feet, you are correct. Did you know that Bose had the contract to provide sound systems to the tenants there? There was the industrial version of 901's in the day room, and an Acoustimass five inch sub tucked under every cot, did you know that the specs for it's size was based on that requirement? Your point on voluptuous sound is well taken, I always prefer twin peaks. . .

    Steve, I only suggested that subs may benefit from the affect of reduced distortion due to restricted bandwidth, I have read about that more than once and it seemed to have possibilities to me. As you mention, very low frequencies are felt rather than heard and I'm a firm believer that size does matter in those circumstances. I also believe that a large woofer will not have problems keeping up with say a 50 Hz signal, given they are used up to 800 - 1200 Hz, so the notion of large woofers being slow is questionable. Also see the picture JBL displayed showing a 15" woofer tracking a sine wave, why did they not do this for a mid or high frequency driver? Or anyone else? I will say my brother's Martin Logan electrostatic speakers are seemingly faster than moving coil drivers, but I just obtained my first LE85's ever, having never heard any either. I can't believe those tiny diaphragms in that magnetic circuit can't track a music signal very well. But I digress. . . What time should I open my windows, it's cold here now and I can't keep them open all the time. I'm wondering if the weird low frequency rumbling heard in some parts of the western U.S. are not a government experiment, but might find their source in some mad horn scientists work??

    All subwoofers are not intrinsically muddy, boomy, or slow, if one is hearing that something else is likely the cause. The Paradigm sub is highly respected from what I've heard and at the very least you should not have much trouble selling it.

  15. #45
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    I just read this post all the way through. To the original poster, yes to the question of whether or not to sub, definately yes. Both for stereo music and movies. I do not agree with many that subs that play well for home theater are different than subs that play well for music. A good sub should be good for both. I have found that in order to provide good sound at a decent level at low distortion levels, multiple subs work best in my room. I use 3 subs, I feel based on my listening experience that I have them tuned in relatively well and over all it depends on the source material. Sometimes I wonder if all the subs have been shut off as there is no low end and then next source comes up and there is the bottom end. Yes they should be unobtrusive and you must take care what sources you use for set up, including sine waves and warble tones and what ever the A/V receiver (if you are using one) has available for set up. In the end, set up to be pleasing to the ear is the best approach.
    If the source materials have the low stuff you will hear it. Yes the opening of Zaruthustra is quite nice, I think one version was measured to be 30Hz. Some of the movies have significant sound tracks with levels as low as 5Hz (War of the Worlds). Significant subwoofage is required for that level of reproduction in the home. My two JBL S120PII's measure down to 25Hz and I have output at 18Hz with my ACI Titan II. All are 12" sub woofers. I find that with a nice set up of subwoofers it adds so much to both music and movies that I can not think of going back, regardless of the "stated" frequency response of the main speakers.
    One of the set up guides from REL stated a good approach, bring the subwoofer up from the bottom - meaning slowly bring it up under the main speakers so that it blends well. Boominess may mean placement issues from standing waves and that sort of thing.
    enjoy the quest . . . .

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