Are Subwoofers, In General, A Waste of Money?

[audio amateur]

Okay, we're talking about relieving speakers from lower frequencies, but this obviously requires high-pass filtering. What is the best/cost effective way to do this in a normal 2 channel configuration? I'm guessing adding this filter results in phase in-coherencies, or maybe not. Thanks for the input

[kexodusc]

Okay, we're talking about relieving speakers from lower frequencies, but this obviously requires high-pass filtering. What is the best/cost effective way to do this in a normal 2 channel configuration? I'm guessing adding this filter results in phase in-coherencies, or maybe not. Thanks for the input

Different ways to accomplish this.
Active EQing is getting more and more popular in the DIY community.
Some people wire capacitors in series with the speakers to filter the lower frequencies. I've done this with mixed results. Phase issues aren't necessarily going to happen, but you'll want to experiment. I found best results selecting a target frequency below the -3 dB point of my towers. When it works, it really works! I prefer a steep filter here at least 2nd order, maybe 4th depending on the speaker.
And of course if you use an a/v receiver for 2-channel stereo you may have the option of using bass management settngs.

My Rotel integrated doesn't offer me that luxury but my receiver does. Unfortunately lugging two 90 lb subs up and down the stairs has a detrimental effect on my desire to listen to music.

[audio amateur]

Different ways to accomplish this.
Active EQing is getting more and more popular in the DIY community.
Some people wire capacitors in series with the speakers to filter the lower frequencies. I've done this with mixed results. Phase issues aren't necessarily going to happen, but you'll want to experiment. I found best results selecting a target frequency below the -3 dB point of my towers. When it works, it really works! I prefer a steep filter here at least 2nd order, maybe 4th depending on the speaker.
And of course if you use an a/v receiver for 2-channel stereo you may have the option of using bass management settngs.

My Rotel integrated doesn't offer me that luxury but my receiver does. Unfortunately lugging two 90 lb subs up and down the stairs has a detrimental effect on my desire to listen to music.

Thanks, but how do you go about active filtering?
Also, what about using filters included on some active subs? i.e. line level in/out or speaker level in/out. Any good?

[kexodusc]

Thanks, but how do you go about active filtering?
Also, what about using filters included on some active subs? i.e. line level in/out or speaker level in/out. Any good?

Active filtering takes place before the amplification state. There's no crossover to deal with in the speaker, the amps are wired directly to the driver. Sonically, this provides a lot of interesting possibilities. You don't do it with speakers that have crossovers in the (ie, commercial offerings) so it's really a DIY thing unless you buy a system with an active crossover.

I think if I was using subs in a 2 channel stereo system, I would use the pre outs to connect to the sub. I wouldn't run the speakers off the subwoofer's filter if that's what you mean. Some preamps have a high pass filter of sorts, but I'm not terribly familiar with them.

I don't know of many subs amps that could accept a full range signal from a pre-amp, apply a filter, and then route the filtered signal to the pre-amp. If such a beast exists I would question if it's as good quality as the rest of your system, and if you wouldn't be better off just wiring a capacitor in series with your speaker.

My towers benefit with the filter in series. I just use quick disconnects to make it easy to plug in, unplug. I could run them full range and just use my subs to augment the bass, but that seems to result in some weird phase issues. Plus it allowas me to take advantage of parametric eq'ing in my room over a wider range. Flatter response at my position.

[GMichael]

Would a BFD be helpful to cut the higher bass to his sub? I missed where he says how his sub is hooked up.

[Sir Terrence the Terrible]

I read a very interesting review by Dick Olsher, one of the reviewers I happen to respect. In this case his opinion struck a cord, given my own experience. Dick-O believes that people spend silly money on subs for a problem that they do not address at all. Subs range of operation without significant distortion is up to 125hz -150hz. But where we invariably perceive a lack in bass energy and presence is in the mid-bass region, which the sub has nothing to do with. For music, I've never been able to get a sub to integrate properly, and I've tried. I guess they're fine for movie effects, or if you want to drive around in a low-rider or pimped-out Escalade booming out earthquake sounds that sound more like Zeus farting than anything resembling music. Otherwise the only sub I will enjoy will be from my local deli.

What do you think?

Payce

Deep bass in movie tracks is more than a bunch of booming notes. There is texture and detail in the deep bass. There is also pressure differences as well. A high quality sub wil flesh this detail out, a cheap or poorly integrated sub will not.

In music, the deep bass is individual sets of notes, not just boom.

I would ask the reviewer would it be more acceptable to have increased distortion during a deep bass passage? This is where main speakers have a tough time reproducing correctly.

[shokhead]

That's why they call it LFE, Low-Frequency Effects . That's different then just deep bass.

[Sir Terrence the Terrible]

That's why they call it LFE, Low-Frequency Effects . That's different then just deep bass.

Actually its not different at all. The LFE channel is used to augment the amplitude of the bass coming from the main channels. Its has it seperate track, but not usually a seperate sound from the mains. It will usually have the same bass as in the main channels, but amplified +10db for added headroom. That way you can mix +10db more bass in it, than in the main channels. If you attempted to mix a completely different bass signal into the LFE than you have in the mains, all kinds of acoustical issues will crop up such as moment to moment bass cancallations and peaks that oscillate in time, even from the same place in the room. This is a unspoken mixing rule amoug re-recording engineers.

[Bigmoney]

A little off subject. I personally cant comment on the sub in a stereo yet, but I have been experimenting the idea. It has been mentioned above, calibrating of the sub is crucial. I have a spl meter and the rives audio test cd. How should I calibrate my sub with my mains runnin full range? Keep in myind my sub has no crossover therefore is just receiving a signal from my rotel preamp and doing what it can with the whole signal.

[E-Stat]

Its has it seperate track, but not usually a seperate sound from the mains. It will usually have the same bass as in the main channels, but amplified +10db for added headroom.

Thanks for the explanation. In my modest HT, I simply use them as line outs for the powered subs.

rw

[O'Shag]

Kex, your listening room is much larger than mine, which is closer to Stat's. Mine is 14x23approx. Like Bluesman, I've had high quality stereo subs running through the Left/right sub outs on my Yammie RX-Z9 and tend to think stereo subs are the best way to go in terms of integration and coherence, although people differ on this (to your point). I ended up selling the subs, because I just didn't need them.

The speakers I've owned have mostly been voiced according to my tastes, with preference for a slightly richer warmer balance with full detailed bass and highly-detailed (yep I'm a detail freak) and transparent mid and high frequencies.I've had the Polk RT5000p (RT3000p, CS1000p, F/X1000), which is probably one of the best movie speaker packages ever IMO. The RT3000p were awesome. Sadly I had to sell them to the guy who lives upstairs - he begged me for 'em. Now, whenever I hear the complex rumbling like an earthquake hit, I know its those speakers - he likes the likes of Iron Maiden, Judas Priest, Metallica etc..

Next were the KEF Reference 107s, which, when called for, have so much prescence and bass that then room will start to shake when the movies get loud. The beauty of the 107s is the bass is of such quality (They look pretty miserable relegated to serve as rear channels in my surround system - but then their big brothers the R109s now occupy the fronts).

Next I got a pair of Mission 767s, Mission's Flagship and their one fling with the high-end. Monster bass, but there not operational now as I'm restoring them. Next, the Monitor Audio GR60s, extrardinary bass response for a smaller speaker, and again that full rich mid-bass. Finally, I got the KEf Reference 109s - The Maidstone, that has the most extraordinary bass I've ever heard, IMO better even than the Wilson Alexandria X2s that I hear frequently at a friend's house.

I tried the subs with most of these speakers, experimenting with several crossover points, but couldn't hear anything that would improve my perception of bass response, extension and quality. I sometimes experienced a degradation of the coherency of the sound, thats why I gave up on subs. Maybe I didn't use a good enough crossover - its possible.

By the way Bluesman, how is that Marsh AS400s? Did you get the premap too?

Stat, that Souther tangiental tracking arm must sound great.

[Luvin Da Blues]

By the way Bluesman, how is that Marsh AS400s? Did you get the premap too?

O'Shag, how's it hangin'. They were all out of premaps so I had to settle for a preamp, damn it. LOL

I picked up the p2000b which has the balanced outs for system synergy. So far the best money I've spent on audio equipment. Now I have to upgrade me speaks, does this never end.
I thinking the PSB synchrony one or the Theil CS3.7s. Comments or any other suggestions that you may have heard with the marsh? Anyhow, thanks for the tip.

[kexodusc]

I tried the subs with most of these speakers, experimenting with several crossover points, but couldn't hear anything that would improve my perception of bass response, extension and quality. I sometimes experienced a degradation of the coherency of the sound, thats why I gave up on subs. Maybe I didn't use a good enough crossover - its possible.

By the way Bluesman, how is that Marsh AS400s? Did you get the premap too?

Stat, that Souther tangiental tracking arm must sound great.

No need to justify to me. I have a simple theory that some people's sense of perception is just different enough that subwoofers aren't acceptable. Our ears, brains, preferences are all different, we won't always agree on what sounds more real.
I also built my subs to specs I wanted. I haven't seen a commercial offering even remotely similar.

I have small monitors on my computer system that roll off around 55 Hz. I can't get them to jive well with my subs for whatever reason. They're used in a small room though and sound fine at moderate volume with the benefit of room gain, so no sub required.

[Ajani]

........

The speakers I've owned have mostly been voiced according to my tastes, with preference for a slightly richer warmer balance with full detailed bass and highly-detailed (yep I'm a detail freak) and transparent mid and high frequencies.I've had the Polk RT5000p (RT3000p, CS1000p, F/X1000), which is probably one of the best movie speaker packages ever IMO. The RT3000p were awesome. Sadly I had to sell them to the guy who lives upstairs - he begged me for 'em. Now, whenever I hear the complex rumbling like an earthquake hit, I know its those speakers - he likes the likes of Iron Maiden, Judas Priest, Metallica etc..

Next were the KEF Reference 107s, which, when called for, have so much prescence and bass that then room will start to shake when the movies get loud. The beauty of the 107s is the bass is of such quality (They look pretty miserable relegated to serve as rear channels in my surround system - but then their big brothers the R109s now occupy the fronts).

Next I got a pair of Mission 767s, Mission's Flagship and their one fling with the high-end. Monster bass, but there not operational now as I'm restoring them. Next, the Monitor Audio GR60s, extrardinary bass response for a smaller speaker, and again that full rich mid-bass. Finally, I got the KEf Reference 109s - The Maidstone, that has the most extraordinary bass I've ever heard, IMO better even than the Wilson Alexandria X2s that I hear frequently at a friend's house.

........

Actually after the 767, Mission produced a new flagship; the Pilastro (about $16K I believe and supposed to have monsterous bass response)...

Mission and Monitor Audio? Sounds like we have very similar tastes in speakers.... Have you tried any of KEF's lower models? Such as the XQ Series.... The XQ40 is the same price as the Monitor Audio GS60.... and the XQ30 and GS20 are the same as well.... So I'm really interested to know how they stack up in comparison....

If your speakers already sound good and deliver the bass you want, then I really can't imagine much benefit being obtained from a sub.... I've heard the theories in this thread and they all make sense (especially if you have bass deficient bookshelfs), but they seem like a lot of effort and expense, when a good floorstander could do the job (for me anyway) just as well....

[O'Shag]

LDB, how are you mate! I think your system is going to sound phenomenal with the Marsh gear. By the way, premaps definitely sound better than preamps If they are brand new components, they are going to take a little while to break-in - probably a few months if you listen quite regularly. They should open-up and lose any sense of grain or harshness. Between the Theil CS3.6 and PSB Synchrony One?? Wow. I haven't heard the Synchrony One, but have heard the 3.6. It is a very good speaker in many ways but It wouldn't really be my first choice, but thats just me. The PSB though looks to be very interesting. John Atkinson, who is not given to hyperbole, waxed lyrical about it in Stereophile last month, saying it reached nearly as high as the KEF Reference 207/2 and Sonus Fabre Elipsa hmmm, I wonder??? But they sound really intriguing. There is another British speaker - that hasn't got any press here, but which is a phenomenal performer. Its by a company called Mordaunt Short and the model is the Performance 6. But the PSBs are a must audition. Also, the Acoustic Zen Adagio is a very good speaker and worthy of your attention. Don't forget the Monitor Audio Gold Signature 60s. And if you really are ambitious, the new Monitor Audio Platinums look to be a killer. Ahhh money money money - where does it all end?? As one audiophile said to another.." I may be broke, but I've got one hell of an audio system" or as that same guy who had just got divorced said to a bird he was chatting up in the bar " want to come home and see my audio system and have a little hanky panky nudge-nudge-wink-wink say no more...

Ajani, thanks - I stand corrected on the Mission flagship. I tried to sell the pair I have on ebay about a year ago for only $600. The 767s were over $7,000 new. I couldn't understand why nobody wanted them, and I was practically giving them away, especially since I was including the Low Frequency Management Unit which is very rare (as are the speakers). I was selling them because I didn't have the space, but I ended up keeping them anyway. They weigh over 200lbs each! It seems we do indeed have similar tastes in speakers.

[O'Shag]

Kex - I think the room size may have a lot to do with the end result. You listening space is a good deal bigger than mine, so controlling excess energy would probably be easier for you, and you probably gave better attention to crossover and DSP than I did. Your technical explainations were excellent, as were Stat's.

[kexodusc]

Kex - I think the room size may have a lot to do with the end result. You listening space is a good deal bigger than mine, so controlling excess energy would probably be easier for you, and you probably gave better attention to crossover and DSP than I did. Your technical explainations were excellent, as were Stat's.

That could be too. Room size/response is always an obstacle.
Most in room responses I've seen of frequencies between 20 and 100 Hz show the huge impact room acoustics plays. It's fairly typical to see a response aroun +/-10 dB. that's a range of 20 dB or more...
Then people tend to place subs near corners for added bass reinforcement. It's wishful thinking to hope we can select a frequencies that picks up from our speakers, and find a level that corresponds. A whole slew of phase issues and response differences between sub and speakers exists. I'm not surprised a lot of 2-channel users don't like subs.
This is one area where digital a/v receivers have some very nice features that contribute to sound quality. The built in filters for bass management allow you to roll-off the response to the mains a bit early so some of the above phase and integration issues are diminished.

I've seen very few pre-amps with any kind of high pass filter on them. There's some nice pre-amp/processors out there though.

[Ajani]

I'm not surprised a lot of 2-channel users don't like subs.
This is one area where digital a/v receivers have some very nice features that contribute to sound quality.

Sadly, 2 channel tends to lag behind A/V Receivers in a few areas because of the simple perception that 1) Digital is bad & 2) Simpler MUST be better (not can be, but must be better)

Even the cheapest A/V Receiver usually has Digital Inputs, but relatively few Integrated amps/pre-amps have a built in dac....

Speaker positioning via a microphone, high pass filters, digital volume control??? Those things tend to be frowned upon by the 2 channel crowd....

Even tone controls are considered audio blasphemy.... worse yet an equalizer....

So how am I supposed to hear a good subwoofer setup like the ones you've all mentioned, when I go into a hi-end store that simply uses a pair of bookshelves and a massive sub with no EQ & no flitering?

When I eventually setup a HT I'll give the theories in this thread a try....

I've seen very few pre-amps with any kind of high pass filter on them. There's some nice pre-amp/processors out there though.

They only one I can think of, that I believe has a high pass filter is the Anthem TLP1.... If I was setting up a 2 channel setup with a sub, I'd definitely try the Anthem.... or if I was even going for a 2.1 channel HT....

[bobsticks]

They only one I can think of, that I believe has a high pass filter is the Anthem TLP1.... If I was setting up a 2 channel setup with a sub, I'd definitely try the Anthem.... or if I was even going for a 2.1 channel HT....

Check this out Ajani for a two-channel with sub rec: http://stereophile.com/integratedamps/306outlaw/