soundsreal - You can "think" whatever you want to. I get to experience it every day.
At the point when bias overwhelms facts I have to step away from the conversation.
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When I say speed in this context I mean ability to produce deep bass through bass (16 Hz - 100Hz). Your average consumer 15" woofer of course will be crappy by 200 Hz or higher.
The reason the "lighter drivers must be faster" is not accurate in this case is because the final, total performance of a woofer is not just mass and inertia but also magnet strength, efficiency and required displacement for a given output. The amount that a 15" woofer has to move for a 25Hz signal is minuscule and far more efficient and lower distortion than an 8". The entire system matters (including the room).
To say a small woofer must be "faster" in bass is like saying a go-cart must be faster than a Honda Civic because it’s lighter. The only way that model is complete is if you are pushing both.
Mind you, I love the 6.5" woofers in my main speakers!! :) But they will never have the deep bass and the speed and glorious output of my 15" sub below 40 Hz.
As hard as it is to properly integrate large speakers into a room, few audiophiles get to hear how magnificent, fast and low distortion a big sub can be.
I'm also really done repeating this. Buy whatever you like, and listen to what you like.
Best,
E
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I’m not sure how many different ways I can type this. If you are thinking of resonance cabinet control it is VERY different than what I am describing.
Imagine an open baffle speaker design of zero mass resting on frictionless rollers. As music plays, the speaker will roll back and forth on the skates, and the acoustic output will be reduced. This is the equal and opposite reaction to the energy of the motor acting on the baffle/motor and motor frame. This is a matter of force, leverage, and mass.
Is it an issue? I don’t know, I have had a number of people whose opinions I trust say they get better bass out of monitors with additional mass, which need not be particularly modern. An antique iron would work if it was heavy enough.
Best,
E
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The weights issue of course is very much speaker dependent. :) I’m certainly not saying it is THE solution to THE speaker problem. :)
This particular issue isn’t resonance within the speaker panels so much as force and leverage vs. the mass of the entire speaker being able to rock the entire assembly. Of course, those of you with 200 lb speakers can ignore this issue.
The woofer motor exerts quite a bit of force that changes rapidly. This could in theory actually move the speaker, or tilt it, causing some self-cancellation akin to the Doppler effect.
Should you spend a lot of time and money on this particular issue? I don’t think so. I used to own Focal Profile 918. Rather tall, light weight speakers with woofers mounted relatively high. That is the type of speaker I think would benefit most.
Having force up high gives it more leverage, and more ability to rock the speaker back on it's rear feet. The Profile was easy to knock over even with after-market supports.
The theory is basic physics, but I haven't done any modelling in regards to "normal" woofer forces and speaker masses. If you are worried, put a nice steel weight on top and listen. Then if you hear no difference at all send me a case of Casamigos tequila on top of which you have written the words "You were totally wrong."
Best,
E
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That a 12/15" woofer is "slow" is a myth, I’m sorry, I’ve proven it over and over again and much smarter physicists than I have explained it. The real issue is that they produce too much deep bass, which integrates poorly in a room without attention. Give me bass traps, EQ and a pair of 15-18" woofers and I’ll scare you right out of the room they are so fast.
As I recall, the large woofers have to move fractions of the small woofer, and have much larger motors, so any issues of mass are more than offset by efficiency (in regards to displacement vs. Hz). Rule of thumb I learned a long time ago, and I may misremember, is that doubling the drivers is the equivalent of using a single driver 2" larger.
So for instance, 2x 8" = 1 x 10" driver. 2 x 10" = 1 x 12" and so forth.
Point is, there is just no substitute for raw surface area if you want deep and low distortion bass. As I noted at the first posting that started this thread, I can really see why this myth is so attractive.
Now, about movement, yeah, you have something, not only the baffle, but the entire speaker can move due to the woofer forces. Cheap fix: Add weights to the top of a speaker. Like 20 lbs at a time. :)
Best,
E
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Good speakers in a good room sound a lot more satisfying than top end speakers in a mediocre room.
Many people have no idea how good even 2-way systems can be properly set up. Proper room acoustics can make them sound enormous.
Best,
E
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gkr:
The amps and speaker matching are certainly a factor. I remember the first time I really heard a difference in amps was watching the dealer swap in a Tandberg to play Snell A/IIIs.
Remarkable power, smoothness and extension. I was quite enamored. The "trick" to the Snell's bass was woofers with significant amounts of added mass however, so it is unlikely these drivers have survived up until now.
I recently owned a Tandberg amp again, though, and have to concur with the original reviews which called them grainy on the mid/treble. << sigh >>
harry:
Very few speaker designers really appreciate the value of designing speakers for a room / location instead of quasi-anechoic. That's how I design mine and it's a huge help.
Best,
E
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Hi @cousinbillyl
Slightly different topic. That is about perceived impact and multi-way speaker design with passive filters. Impact is not actually deep bass. That’s just regular bass. :)
A powered subwoofer would skip the inductor/filter issue altogether.
Not the first time I have read this statement, so there may be some truth to that, but there are a couple of myths too. Good cored inductors with very low DC start rather inexpensively. The issue with designing a low pass filter is more complicated than merely reducing the DCR. No one should start replacing coils willy-nilly. There are a number of issues that can be introduced by doing so.
Best,
E |
Dave, I'm now in a completely open floorplan, so no room loading. Previously, yes!
Rather than the Behringer, I like the miniDSP line. Easier to control via windows UI, and I can feed it directly from OmniMic. I measure the response and then have OmniMic calculate a correction curve, and I'm done.
What I like about OmniMic is my ability to tailor the target curve. I usually go for a 1 to 2 dB/octave descending slope starting at 16-20 Hz for the sub. JL does a similar thing.
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For measurements, if I'm not using OmniMic, the Android app AudioTools + the Dayton IMM6 microphone is a real godsend.
Best,
E
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I can be quite brave when I say I could not justify $12k on a subwoofer. :)
Your wallet may be less prone to pain and suffering than mine however, and I welcome you to spend as much as you'd like.
I will say that I have plenty of output and my HT has as much output at 16Hz as I want or need. My previous apartment was even better sounding than this one, but I'll survive.
Best,
E
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gdhal,
We are not going to agree there, at all.
Best,
E
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Did a little searching on data-Bass.com
At least on paper, the rotary woofers don't seem to do all that great compared to far less expensive solutions. Seem to be just as output and distortion limited as their coned counterparts, or at least close enough to make the $12k price tag questionable.
Best,
E
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I have seen a couple of takes on the fan as a woofer idea.
Just FYI, as Dr. Leach was fond of saying, 0 Hz isn’t a sound, it is wind.
Another was kind of a corkscrew in a tube. Seems to be long disontinued, the Phoenix Gold Cyclone by BNIB.
Another way to use a rotating motor is converting the rotation to linear travel with a flapper, like the Devialet.
Neither method really resolves room mode issues and trades motor strength for effective surface area. As a signal drops an octave, displacement must increase by a factor of 10 for any given driver, so 1mm at 40 Hz becomes 10mm at 20 Hz, and so on.
Fans, assuming they can spin fast enough, eliminate the excursion issue. No idea about distortion figures. I can say that with a Hsu VTF 15 I can get monstrous output in room at 16 Hz, so not really a problem I need to solve.
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The issue with deep bass is that it requires sacrifice to implement. Remove every sacrifice, and you are left with two choices: - Bass limited systems
- Muddy sounding, unpleasant bass
And while audiophiles are accustomed to sacrificing in some ways, the ways of deep bass require sacrifices a lot are unable or unwilling to make. For instance, adding an EQ. Well, you just spend $80,000 on a new dCS DAC stack, you are going to be really unwilling to put a new ADC/DSP/DAC in your chain. This is one good reason for using a sub, so the EQ stays out of the chain of your main speakers. Bass traps are another sacrifice. It’s not just money, GIK’s Soffit Traps are quite affordable, it is also floor space and WAF. I know of some audipohiles who refuse to do any room tuning at all, but will spend thousands on cables. UGH. Talk about badly balanced priorities! Then of course there is the amount of time it takes to learn and appreciate the integration a sub requires. It must integrate to the room and the speakers. In addition to finding the best location you are playing speaker designer when you do this, so a background in crossover design is a big help in configuring the EQ and crossover settings. This is a lot of work to develop a skill you will need once. Alternatives are subs with really good auto-EQ, like JL Audio. Overall too expensive, but really good auto-EQ. When shopping for a subwoofer the most important aspect is the quality of the auto-EQ features. Advice from owners is a big help here, as is an in-store demonstration. HT receivers have this feature as well, with wildly different results. For all these reasons, I think, an audiophile is right to be trepidatious and maybe even avoid really deep bass. The smaller speaker isn’t faster, it is easier to live with and less likely to bait the dragons that lie in the last 2 octaves. From an overall balance, a limited bass speaker is usually much more room friendly, and therefore, more satisfying to live with. |
