Will I benefit from a subwoofer with 20Hz speakers?
My source is a minidsp shd studio with Dirac going into Denafrips Gaia DDC to Denafrips T+ DAC to McIntosh 601 Monoblocks to Cabasse Pacific 3 speakers. The speaker's published frequency response is 41-20,000Hz. I presume this is achieved in an anechoic chamber. In my room however, it goes down to 20Hz, at least according to the Dirac measurements. In fact, I needed to flatten the curve and reduce by 5-20 DBs between 20-100Hz due to the room effect.
So, considering I already go down to 20Hz, is there anything else 1 or 2 subwoofers will do for my system? Would it create a more consistent low frequency field? I see many people adding up to 6 subs, so I wonder what I'm missing.
"...most of the energy that drives your system will be shunted to drive the subs, and your amp driving the main speakers will be starved and get only the meager leftovers that the sub graciously allows."
That should not the case if the sub is active. The main speakers will not be affected much but if you have high-pass filter (HPF) in between, then it will leave more headroom for the amplifier to dirve only the mid and high and therefore more efficiently. In fact, I found, without HPF, the integration of sub with the main speakers wont be as good because the mid-bass was often boosted a bit hig to my taste.
I will play the devils advocate here. While adding a sub has the potential to add LF quantity and / or quality, it will invariably take away from the signal strength going to your main amp / speakers. That is, you need to make compromises at the low signal level, which might be quite steep especially when the subs plate amp with super low input impedance guzzles the current away from a tube power amplifier with high input impedance.
No, this isn't a thing. With preamps easily able to under 1 kOhm loads, and amps presenting 25k Ohms and higher loads there is a barely measureable change to the preamp output at the same setting. Do the math. Assume a perfect voltage source with a 1 kHz output impedance. Takes a lot of 25kOhm amps to cause a change.
@dmilev73Yes you will definitely benefit from a sub or 2 or 3 When this is suggested people think of being overpowered by thunderous bass which if properly implemented is not that at all. Think of the subs as tuning devices. An enlightened poster mentioned a SWARM and I encourage you to read up on this. (aka DBA)
But the thing is that rooms and speakers are random.
This comment displays a lack of understanding. If nodes developed randomly it would be impossible to treat them because you have a moving target. Any given speaker in room will set up a consistent pattern if nothing is added or removed and the doors, windows and drapes are left as they were when first measured. Come back in a week or a month and the room will measure exactly the same. Nothing random about it.
@lanx0003, Who told you to toe-in your speakers to cross in front of you? This relies on the proximity method and works with speakers that use constant directivity waveguides and a power response that is even. A 180 degree waveguide, like the ubiquitous dome tweeter will not work which is probably what you have. A CD waveguide toed-in like you tried provides great imaging and a nice w-i-d-e listening area.
@lemonhaze Erik (@erik_squires) has advised so. So let me get this right since it is kind of interesting. You mean if you had CD waveguides tweeter like horn, you will benifit from toe-in to cross in front of you as it will provide great imaging and wide soundstage AS COMPARED TO straight or slight toe-in, right? I wonder what is the "theory" behind it but will definitely give it a try when I get or audition speakers with CD waveguide tweeter someday. It may be my biased preconception but I never had an interest for horn speakers as it are a bit too bright for my taste. But maybe some other less "agressive" (not sure if this is a right description) CD waveguide tweeter speakers will serve me better.
It’s good you’re using Dirac in that room otherwise your system would be unlistenable because of the bass amplitude.
But I’m not sure there is a need for using Dirac above 500hz.
And, don’t trust the Dirac curve too much. If you measure your system as @djones says you will almost certainly get something else. And what you measure right now may also be distortion to a great extent. The freq. curve is just the beginning.
I use some Dirac for the bass yes, but then apply Roon eq according to my hearing.
I’m not of the opinion that Dirac and similar dsp tools gives a too lean bass. Quite the opposite. Don’t trust the smooth calibration curve.
I also use a phenomenal sub to my true 20hz speakers. For the possibility to show off when someone wants more bass :-) but also for HT use and for the fact that some recordings really need a push down low.
More subs will also give you a better distributed bass in your room, some says. I’m not so sure that will help a lot. You’ll still have peaks and dips.
@dmilev73My main speakers are flat to 20Hz. But at the listening chair I have a cancellation, so no bass at that location, while nearly everywhere else in the room the bass is fine.
So I added a pair of Swarm subs. One is to my left, immediately against the wall (I actually have its driver facing the wall about 2" away and the other is behind me and to my right, set up the same way (the Swarm subs are designed to take advantage of the room boundary effect and so are meant to be directly against the wall; most subs are not). Because of the asymmetrical placement, the subs are able to break up the standing waves caused by the room itself. You can turn the subwoofer amp on and off; the difference is dramatic. Off- no bass, on- bass, off- no bass, on- bass. Obviously I leave the sub amplifier on.
So yes, additional subs can help out speakers that go to 20Hz all on their own.
Here are some facts to understand how this works:
1) the ear can’t know the bass note is there until the entire waveform has passed by it.
2) at 80Hz the waveform is 14 feet long; so by the time your ear knows its there, the waveform might already be bouncing off the wall behind you.
3) the ear can’t tell the frequency until a few iterations have passed. By this time the bass in the room is 100% reverberant.
4) because of 3), a mono bass signal can be used for the subs.
5) if you keep the subs from having any output above about 80Hz, they won’t attract attention to themselves.
6) the asymmetrical placement is important for breaking up standing waves.
More subs will also give you a better distributed bass in your room, some says. I’m not so sure that will help a lot. You’ll still have peaks and dips.
Yes, you still have peaks and dips but they are much smaller and are all over the room. Because there are so many more and they are less than 1/3rd octave apart the ear won’t acknowledge them. So it helps a lot!
This comment displays a lack of understanding. If nodes developed randomly it would be impossible to treat them because you have a moving target. Any given speaker in room will set up a consistent pattern if nothing is added or removed and the doors,
Thanks for taking my comment out of context, @lemonhaze
My meaning was that most audiophiles should not take the -3 dB point of a speaker and think that it means much once it is in a room. While the physics of room modes is understood, the final -3 dB point of a speaker in a room is not something anyone can gauge well by back of the envelope calculations. That is what I meant by "random" and why I encourage measurement as a much better place to start than speaker specs.
Room mode simulators like the great one from AM Acoustics are fantastic tools which should be leveraged when considering room treatment, and I encourage it’s use as well.
This is really a side comment and doesn't apply to main speakers vs subwoofer. I have found that frequency response down to 20 Hz is not necessarily that important, especially for music. There are definitely recordings which you can get that do go down to 20 Hz, but they are a rare item. If you really look at how most people respond to bass in music, the most important area is the 40-70 Hz area. That is where we feel and perceive most of the visceral impact of bass. The low 20 Hz rumble is nice, but if you have a hole or bass null at 50-60 hz, you will feel a significant lack of bass.
Oh, one more note. I would be very careful about using Dirac to eq the response of these speakers flat down to 20 Hz. The Cabass is stated to having response down to 41 Hz, which is definitely possible with the right 6.5" drivers. However, past a certain point, the driver response is radically reduced the closer it gets to 20 Hz. While those drivers -could- be reproducing a 20 Hz signal, the actual sound level can be something like -20db or -30db. This means that Dirac is putting a +20db eq for the 20Hz point and will create a massive over-excursion of the speaker cone if you do actually hit a sound with this frequency. This will definitely cause the woofers to either peak and clip - and can damage your speakers.
IMHO don't waste your money. There is very little musical content in that octave 20-40Hz and in my experience having too much bass becomes annoying after a while.
@bishop148, did you not read the thread? If you did you would have seen my short explanation and @atmasphere's clear and informative take on the virtues of multi-subs.
Perhaps you do the OP and yourself a disservice with your ill-informed dismissive reply.
@lanx0003, a constant directivity (CD) waveguide and a horn look about the same but behave differently. Generally speaking waveguides do not exhibit any of the annoying traits that gave horns a bad name. A CD waveguide in addition to allowing a wide sweet spot also has extremely low distortion and seemingly unlimited dynamics whilst also providing a believable stage.
They are not bright if correctly implemented and I find superior to any dome tweeter. In a domestic situation they are virtually indestructible.
As I've mentioned before: Pink Floyd don't play through dome tweeters 😎
There is very little musical content in that octave 20-40Hz and in my experience having too much bass becomes annoying after a while.
@bishop148The point is not more bass! The point is to get the bass right. If the bass is deficient, the ear will perceive the system as being tilted to the highs; if there is too much bass the ear will perceive the system as being muffled in the highs.
If you listen at mid volumes (or your room is large) then a sub should be of some benefit, If you listen some of the time at low volumes then a sub will always be of great benefit. You can do the equalising thing (early amps always had a 'loudness' button!) but a good quality sub is the better way.
Sometimes speakers image better crossed in front. Depends on a lot of factors, but what this tries to do is minimize early reflections from the side. If you don't have early side reflections this can't provide any benefit, but being only important in the mid-hi frequency range it's OT for this conversation.
To all the nay-sayers, please take a look at the OP’s data. Notice how the original measurements showed output at 20 Hz very close to the output at 1 kHz. This is despite his speakers being rated to -3dB at 40 Hz.
This is a very similar situation to the one I wrote about in my blog and why I keep saying measurement is important, and we may be adding subs for the wrong reasons. Let the OP clean up his bass first, and then decide, based on his own needs and values if a sub is worth the trouble.
In terms of what this SHOULD Be, I am going to go with Floyd Toole and Anthem's ARC room gain recommendations. Below 100Hz there should be a shelf of around +3 to +6 db. Basically this is "salt to taste" when it comes to bass levels, and follows my overall process:
@bishop148 The point is not more bass! The point is to get the bass right. If the bass is deficient, the ear will perceive the system as being tilted to the highs; if there is too much bass the ear will perceive the system as being muffled in the highs.
What you say is true, however if you were use a low cutoff filter at 40Hz. With most music I doubt if you could hear the difference. A subsonic filter cuts in about 40 Hz and I could never tell the difference apart from stopping the excess movement of the bass speaker.
@erik_squiresAgain, if you do a life music recording out of the 40Hz-20kHz speakers and the flat 20Hz-20kHz treated room, your claim will be much more convincing. Post it on Youtube and you will be famous. Why not? Your audiences should not be limited to audiogoners.
@lanx0003- The day you pay me to do this is the day you get to complain of what I have or have not done. I ignored you because I have other things to do, and other priorities in my system, which will continue to be true.
Since I make no money either way based on whether or not audiophiles take my advice or not, make of my postings what you will.
If you think I am in error I suggest you post your own findings, and actually do something instead of complaining that I haven’t done enough for you, because the level of obligation I have to you or anyone else on this site is ZERO and I'll be damned if you or anyone else on this site gets the impression you have any say so in how I spend my precious free time.
@erik_squires You owe nothing to anyone or me. Your voluntarily service to the audiogoner in the community is beneficial as I have complimented previously. However, when you make such a strong/powerful claim and try to maintain the credentials when others challenge, the burden of proof is on you. It is a reasonable doubt that what you have measured is one thing but what is actually heard is another. It is your decision to do what I have suggested, which is another way to disprove something that I and a circle of friends of mine don’t believe achievable. We all do not believe will be so "lucky" as you are...
Oh, BTW, last time your advise toeing speaking in front of MLP and I reply with the shrinkage of SS as a result, you ignore too. Is it another way of yours admiting something you have advised is wrong? Ignore again. I don't care but just wish get some mindful message across so others will not follow the wrong footstep.
You have responded well to the OP's original concerns, and I for one appreciated the dialog. You've not only laid out a reasoned approach for assessing one's existing setup, but documented some very economical tools for doing so.
It makes perfect sense in these cases to collect more data and learn more about your system/room before laying out $4K or so in subs. I for one would definitely go this route.
The notion that you failed to make your case - for questioning the accuracy of published speaker ranges without also considering room effects, - is ludicrous.
You gave some good examples, including specific comments on OPs speakers.
Even Hans Wetzel's review of the Cabasse Pacific 3 mentioned by @dmilev73 - but apparently not read by the skeptics, alluded to the same point:
"The speaker’s claimed 41Hz lower limit must be an anechoic measurement; with room gain, I’d be shocked if they didn’t have solid output down into the low 30Hz range, possibly even the high 20s."
My point, and I made it after my head got hot, is that rather than demand I do more work, others should instead follow the discussion and contribute their own findings.
Honestly, I am super curious about seeing data from audiophiles comparing their speaker’s published spec and in-room response. I would learn a lot from that.
Very little benefit, IMHO, would come from me recording my system, and honestly, I don’t have a lot of time and energy for this. The more others contribute their experience the better the elephant will look.
I am by no means anti-sub. I love subwoofers, but consumers should be clear-eyed about where their system is starting from and what problems or benefits they hope to achieve.
I have _never_ seen anyone regret analyzing and treating their room before adding a sub, but I have seen some decide not to sub.
What you say is true, however if you were use a low cutoff filter at 40Hz. With most music I doubt if you could hear the difference. A subsonic filter cuts in about 40 Hz and I could never tell the difference apart from stopping the excess movement of the bass speaker.
A filter has a cutoff frequency that is defined as the -3dB point. You will get phase shift above that frequency; up to 10X the frequency if a 6dB/octave filter is used, less if a 12dB filter is used but you get more of a 'bump' just above the cutoff. The ear perceives the former as a loss of impact.
I played bass in the orchestra for decades and now play keyboards in a band; I like electronia and there are plenty of ambient recordings that have significant material below 40Hz (roughly low E on a bass). Having a number of speakers laying around, I've two sets where the cutoff is about that frequency and I most definitely miss the bottom end using them without subs.
Yuo tell us acoustics is simple. Put two small swarm subs in the room and your ears won’t hear any peaks or dips. Well, to me it isn’t.
I didn't say acoustics is simple. What I did say is that setting up a set of Swarms is quite easy. I experienced immediate improvement. Also, I only use 2 Swarm subs because my main speakers are flat to 20Hz. I got away with 2 subs but most people would need 4. I can cycle the subwoofer amp on and off and the difference is obvious.
@erik_squiresThe data sure seems to suggest a standing wave. There is a dip of about 8dB and then a peak. If this is at the listening chair as described it should be outside the room boundary effect. A bit depends on the room of course. But since we have that dip, no amount of power will correct it since its cause by cancellation. That's why you break up the standing wave with a distributed bass array. Then if the room still has issues they won't be hard to correct.
why I keep saying measurement is important, and we may be adding subs for the wrong reasons. Let the OP clean up his bass first, and then decide, based on his own needs and values if a sub is worth the trouble.
My point is you swarm guys always make it sound so easy. It’s not. Theory is fine. You might very well be able to break up a significant dip or “null”. But peaks and dips will still be there in a normal room and will need eq to get fully satisfactory bass. But I agree on driving high quality speakers all the way down and adding sub or subs to that.
While the vendor's promotion online has been fair and honest the fan boys of this system are out of control. From reading their posts and their attacks of the ideas posted above it is clear to me the fan boys have never heard a well integrated single sub so their opinion of any other ideas is at least misinformed if not down right deceptive.
@erik_squiresI've read this before (and the rest of it). I certainly don't agree with it either in tenor or theory. For one thing, I'm not a 'fan boy' (I think there was someone posting here who was, who is either deservedly banned or moved on). I've known Duke Lejuene of Audiokinesis (the primary manufacturer of subs specifically meant for use in a DBA, the Swarm) for 25 years. He is one of the more honest people you can deal with in high end audio, and is well educated in speaker theory and design. I've seen Duke pushing the DBA concept now for nearly 20 years. He's garnered 4 Golden Ear Awards for the Swarm simply because it works.
I don't find the application of a DBA in my installation to be particularly cumbersome or complex. Since I prefer the idea of running the subs off the preamp rather than speaker level (to avoid colorations) the use of a subwoofer amp in my equipment stand was easy to execute. I do run long speaker cables, but they are inexpensive- the kind that has one 'silver' conductor and one copper, like you get cheap at a hardware store. I think one run is about 22 feet. I just did this to see how well it would work temporarily, and it worked so well that I see no reason to change it.
Is it possible that since you've not tried it, you might have some mistaken impression about the complexity? The whole thing took me 15 minutes to set up and about 2 minutes (by following Duke's instructions) to dial in. Pretty simple IME.
Now I have several systems in my home. The main system, the home theater, my bedroom system and the basement system. Of those a DBA is only used in the main system. There are single subs in two of the others. To be clear, I'm acquainted with the idea that you can make a single sub work. In one system, I lucked out and the only place the sub could go works fine. In the bedroom system, I had to move the sub around until I found a spot that it could be heard when in the listening position- the most convenient spot rendered it inaudible due to cancellation (standing waves).
My point is you swarm guys always make it sound so easy. It’s not. Theory is fine. You might very well be able to break up a significant dip or “null”. But peaks and dips will still be there in a normal room and will need eq to get fully satisfactory bass.
You are partially correct here- Duke of Audiokinesis says the same thing you do: that the big peaks and valleys are eliminated and in their place are much smaller peaks and valleys which because of their small size become hard or impossible to detect by ear. Duke also says that after than has been done then use room correction and possibly bass traps to really get the room right. So you and he are nearly on the same page.
The formula here is that a DBA does about 95% of the bass correction needed in most rooms (by eliminating standing waves), and room correction and bass traps do the other 5%. The question of this thread though is there benefit to subs if your speakers already go to 20Hz and the answer to that is certainly 'yes' (if used correctly).
I mentioned above it took me about 15 minutes to set up my Swarm setup (keeping in mind I have two Swarm subs, not four, since my main speakers go to 20Hz already). Once I placed the subs (against the wall, out of the room traffic and mostly out of sight) I've not had to move them and I've not had to mess with phase. Pretty easy (so you can blame me for saying that), easier than my bedroom system where I had to crawl around and move the sub bit by bit to get it right.
Each to his own of course, I don't begrudge anyone who doesn't want to do it this way, but FWIW as I explained I have subs installed several ways. IME regarding this topic, those who denigrate this approach really haven't tried it.
Sounding like a fan boy myself, @atmasphere@erik_squires both have decades of experience and knowledge.Myself and many others here have benefited from it and been inspired to do more research then do our own experiments and implementations.As far as this discussion Erik and Ralph just start from different points IMO.
The Amroc chart Erik mentioned I ran across a few years ago - calculates your room modes in seconds,a good place to start.The site is very informative and easy to understand for us tech challenged folks(me).
I've got room treatments and three subs,only one sub has DSP included. What a huge positive difference that equalizer makes....if the other two ever fail I know what I'll be replacing them with. My speakers do go down to 20hz but their position isn't ideal for the best bass response even though the mids up are the best they can be in my room. Just my two cents.
Sorry being so stubborn, but "eliminate" - no, "reduce" - yes. If you start from +/- 15 db shifts or more in the bass region, which most of us do (look at the measurement the op did), then I’d say there is no way a swarm setup will flatten that out so you won’t hear any peaks/dips . If using several subs can reduce that to 50% or +/- 8db that’s great. And above all remove any "nulls" (infinite dips) while they can not be corrected with eq (dsp).
Sorry being so stubborn, but "eliminate" - no, "reduce" - yes. If you start from +/- 15 db shifts or more in the bass region, which most of us do (look at the measurement the op did), then I’d say there is no way a swarm setup will flatten that out so you won’t hear any peaks/dips .
No worries- I can't say I'm not being stubborn either. I can turn the subwoofer amp on an off in my system and the difference is dramatic. I was missing the range somewhere around 40Hz, which the Swarms sort out nicely.
Some soundtracks will be missed by a subwoofer that cannot emit frequencies below 20Hz. Bass may be sensed much below 20Hz. Few things can give you a guttural sensation in the pit of your stomach like bass that low. However, many films will not even feature frequencies so low. - five nights at freddy's
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