Subwoofer for Magnepan MMGs?

[KnightRT]

This is a two-part question:

1) I have an H100. It seems to be slightly behind my mains. Is there any way to adjust the delay for the mains, or speed up the signal to the sub? Changing the phase switch doesn't seem to help.

2) I'm looking very hard at a set of Magnepan MMGs. They're rated 50 hz-24 KHz +/- 3db, though from user reviews, I suspect that bottom end is optimistic. I'll need a subwoofer.

The system will be in a 15x15x10 room on the top floor on apartment. I'll be using it exclusively for music (film scores, classical, acoustic, vocals) at moderate volumes. The flooring is wood.

As above, I have an H100. It has strong response at 30 hz, which I don't really need (or want for the sake of neighbors) with music. It's also quite large.

Ideally, I want something for ~$300 or less with a 10 inch, or even an 8 inch driver that'll keep up with the Maggies, and won't be horribly difficult to blend with them. It should have quick, clear response from 35 hz to about 90 hz.

I'm perfectly content with the quality of sound from the H100. I don't need anything better than that, so long as it isn't obviously inferior to the Magnepans.

What would you suggest?

Thanks,

Dave

[Willd]

Well that UFW-10 sale for $399 would have been a good choice.

[nathan_h]

At that price range, HSU is difficult to beat -- but you'll get the most mileage buying used, of course, no matter which brand/model.

[The13thGryphon]

I'm not sure you can get a sub to truly compliment the Maggies for $300. I have been going through a very similar dilemma, as I have a pair of Magnepan MC1's that I'm using in my 13.5' x 15.5' x 9' den.

Maggies are incredibly fast, and very dynamic -- within their limitations on total volume. Their micro-dynamics in particular are fantastic. This makes matching them with a sub a bit more challenging than is true for many speakers. Not impossible, mind you... just more difficult.

I think you'd do better with an acoustic suspension (sealed box) subwoofer, rather than a ported, slot loaded, or even passive radiator design. This is due to the cleaner sound -- in general -- of the acoustic suspension design. The other designs are more efficient, and they usually provide deeper bass at a more cost effective price... but they are just not as fast, and just not as controlled. Their sound is not as "tight" as an acoustic suspension sub.

It is my opinion that vented (or bass reflex) units and subs with passive radiators give great "bang for the buck" (excuse the pun), but that for truly musical subs, you need a sealed enclosure. Others may disagree, but I feel this is particularly important when the main speakers are planar magnetic (Magnepan) or electrostatic.

Personally, I chose the Rocket UFW-10 by Onyx Speakers. I know that even on sale they were a bit more than you wanted to spend... but again, I'm just not aware of a decent acoustic suspension sub for that kind of money. Unfortunately for you, I think the sale is now over. You might contact them and see if there are any B-stock units available. That would get you one for around $450 with shipping. The KEF PSW2500 is also a very nice sounding sealed sub... though it too is in the $600 range. You can get a Bob Carver Dominator D10 for $449 right now. Though I haven't heard this sub personally, it is getting good reviews on the boards.

If you just can't spring for that, or better yet, the Rocket UFW-10, then I'd look for either a HSU Research STF-1, or an Outlaw Audio LFM-2 (recently reviewed by Secrets of Home Theater and High Fidelity -- see link below), or a Mirage Omni 8. Each of these three subs can be had for about $300, and all three have been critically acclaimed in their price range. Given the vented design, they're not bad. Due to the fast response of the smaller 8" driver, they may work reasonably well with your MMGs. If you can't afford a sealed sub, then one of them should at least integrate better than your H100, anyway.

http://www.hometheaterhifi.com/volum...06-part-1.html

Good luck, and good hunting.

[Willd]

Due to the fast response of the smaller 8" driver, they may work reasonably well with your MMGs.

Smaller drivers (8") do not "respond faster" than larger drivers (12", 15"). That is a myth.

Just thought I'd clear that up.

[Cruzin]

Whether they do or not,smaller subs,8 or 10",seem to match better with the maggies.Maggies are such a quick responding speaker that I agree ,they are harder to find a sub that compliments them well but it can be done.

I run a dipole subwoofer with my Maggies,one of the few ever produced,and it does do justice to the Maggies.

[KnightRT]

Smaller drivers (8") do not "respond faster" than larger drivers (12", 15"). That is a myth.

Presuming all other factors equal, a smaller driver with less mass should respond faster. Why would it not?

Gryphon, that was a very informative post, thank you. The Hsu subwoofer looks appealing, even if it is a ported design.

It's very difficult to find comments on the 'musicality' of a subwoofer. Most of the reviews are concerned only with how hard they thump.

Do you suppose an inexpensive sealed subwoofer would outdo a more expensive ported one? Actually, let's back up; are there any sealed subs of decent regard in this lower price range?

Dave

[Willd]

Originally Posted by KnightRT

Presuming all other factors equal, a smaller driver with less mass should respond faster. Why would it not?

Gryphon, that was a very informative post, thank you. The Hsu subwoofer looks appealing, even if it is a ported design.

It's very difficult to find comments on the 'musicality' of a subwoofer. Most of the reviews are concerned only with how hard they thump.

Do you suppose an inexpensive sealed subwoofer would outdo a more expensive ported one? Actually, let's back up; are there any sealed subs of decent regard in this lower price range?

Dave

The larger drivers do not have to move as fast in linear velocity to reproduce the same output frequency and power as smaller drivers. So, yes, the smaller drivers actually have to move faster, but I was referring to The13thGryphon's assumption that subwoofers with a smaller driver "have a faster response" than subs with larger drivers.

Assuming both subs have a good transient response, the size of the driver doesn't matter.

[Nick250]

An opinion from out in left field. I have a six year old Hsu VTF-2 sub. The big old black bumpy finish ones from way back. I could not be more pleased with the way it handles music. I just received a brand new Rocket UFW-10 last week and first impressions indicate it has nothing over the old Hsu for musical reproduction. The speakers are Paradigm Studio 20s v2.

I have never heard the MMGs so take this for what it's worth, however an 8" or 10" Hsu may be worth considering. YMMV and all that.

Nick

[Dermott]

I have Maggie MMG's and a Rocket UFW-10 and I think they are great together. I have the Maggies crossed over at 80 and they seem to blend fine. For what I wanted, sealed was the way to go though. The quality of the base from sealed subs to me just seems cleaner and more musical. That being said, if one was going to go with a ported sub, Hsu would probably be my choice. Upon my recommendation, my parents have a STF-2 in their system. It is musical and has more overall output compared to my UFW-10. The Rocket does have a tighter sound which was what I was looking for to mate with the Maggies. If music is your priority, Maggies and a sealed sub are an excellent way to go.

[Jack Gilvey]

Smaller drivers (8") do not "respond faster" than larger drivers (12", 15"). That is a myth.

Of course.

I run a dipole subwoofer with my Maggies,one of the few ever produced,and it does do justice to the Maggies.

A dipole is also my suggestion, but few go that route since it's almost gotta be DIY. Compared to a dipole, sealed/ported/PR sound much more like each other. Which make is yours?

A small, sealed sub is a great choice for MMG's, not because it's "cleaner" (at least not in a distortion sense), but because MMG's don't get really loud anyway. It's easy to make a small sub that's linear down to below most music. It's also a very easy DIY project, if you want something that'll perform out of the price range.

[Cruzin]

"A dipole is also my suggestion, but few go that route since it's almost gotta be DIY. Compared to a dipole, sealed/ported/PR sound much more like each other. Which make is yours?"

My sub is an old old M&K mx-2000 that I've recently picked up.Its circa 1990 and was M&K 's very first push pull design.While they still make the push pull designs,none are dipole(they have 1 driver facing forward,and one facing down).

When I took it to M&K for a refurb,and talked to the tech guys,they explained about the dipole design of this particular sub.The only dipole model they ever made.

Sorry Op,dont mean to hijack the thread.

[soho54]

1) To fix this you have to adjust the sub and speakers distance setting in the receiver. In some rooms you have to play with the distances to get them to mesh properly. Try setting the sub closer and the speakers further away, and vise versa. Then you have to go back and adjust the rears (if present) to the front and your all set. Room treatments work better but the receiver trick can get you 75-80% there, in this regard.

2) Yes a sub is a definite.

I would get the MMGs and use them with the sub you have for a little while. That way you can learn what you like and dislike about the sound of the sub with the Maggies. That way you will know what qualities you personally want from a new sub. Who knows, they might sound great together and you will not need to get another sub. Sound is all subjective and personal with most things.

[soho54]

By the way, if you are into DIY you might want to checkout this thread: The Maggie Projects

[Jack Gilvey]

My sub is an old old M&K mx-2000 that I've recently picked up.Its circa 1990 and was M&K 's very first push pull design.While they still make the push pull designs,none are dipole(they have 1 driver facing forward,and one facing down).

When I took it to M&K for a refurb,and talked to the tech guys,they explained about the dipole design of this particular sub.The only dipole model they ever made.

Ok. It's not dipole in the acoustic sense I mean, those M&K drivers are in-phase so it's still a monopole acoustically. If anything, it's a bipole.

http://www.linkwitzlab.com/woofer.htm

Here's one in its simplest form, my open-baffle U-frame with Adire DPL-12's:



It radiates directionally due to the cancelations to the sides from the out-of-phase back wave.

[KnightRT]

Very useful advice from all. As per Soho's advice, I have to spend more time with my receiver's instruction manual.

As I don't feel there have been huge advances in subwoofer technology in the last few years, older models that I can find via auction sites and Audiogon at a discount are also appealing. Perhaps an older sealed box, if I decide the Hsu in inappropriate. What was the sensation du jour 5-10 years ago, I wonder?



Dave

[The13thGryphon]

Originally Posted by Willd

Smaller drivers (8") do not "respond faster" than larger drivers (12", 15"). That is a myth.

Just thought I'd clear that up.

Let's discuss a little lesson in physics...

Mass - The mass of the driver cone and voice coil determines transient response and overhang, in other words, the time required for the driver to start and stop moving. This start and stop speed determines how faithfully it follows the input signal and what you hear. Larger, heavier drivers typically -- not always, and not without exception, but usually -- will respond more slowly than smaller, lighter drivers. Subwoofers are subject to the laws of nature just like anything else having to do with mass and acceleration. The larger the driver in the subwoofer, the greater the mass and therefore the greater the difficulty in starting and stopping this mass.

Rigidity - Because a subwoofer needs to move a lot of air to recreate low frequencies you can hear and feel, they need to be resistant to deformity from the significant air pressure pushing against the driver inside the cabinet. Therefore, the subwoofer cone, frame and cabinet need to be rigid in order to provide the required force without the deformation that causes distortion. This applies to larger drivers even more so than smaller drivers. A large driver has to be even more rigid to keep from deforming and causing distortion. Therefore, typically -- and again not in every case, but by and large -- smaller drivers will be easier and less costly to produce. Therefore, in inexpensive subs, a smaller driver can be a desirable option.

[soho54]

edit

[Willd]

It isn't a lesson when you copy it from a website.

Try to form your own thoughts/opinions every now and then.

[The13thGryphon]

Originally Posted by Willd

It isn't a lesson when you copy it from a website.

Try to form your own thoughts/opinions every now and then.

So, if a concept is already published or printed in some fashion it is not considered valuable? It cannot be utilized to deliver a lesson? That would obviously be news to the vast majority of public and private schools as well as colleges and universities throughout the world.

I never stated that the information was my original work. Just as you, in all likelihood, did not actually perform scientific testing under controlled conditions, or perform the mathematical calculations required to demonstrate the actual physics involved to come up with your theory that smaller drivers do not move faster than larger drivers. You -- again, probably... I'll stand corrected if you actually did -- most likely utilized the work and words of others when formulating that opinion.

I did formulate my own opinion... through observation and listening. What I stated is what I've personally experienced. I did derive my own thoughts on the matter, which I stated -- in my own original words -- in post number 4 of this thread. I will readily admit that when you derided my opinion I resorted to referencing material from a knowledgeable and respected source to support my own previous comments. If that particular source is inadequate in your mind I can easily reference others. Would the physics department of a major university be more acceptable to you?

Seems to me that use of well thought out and previously vetted materials only strengthens my position and opinion... but apparently you don't recognize published text or reference, or at least you don't believe that use of such materials can constitute a lesson. Interesting belief system you have... or is it just the fact that I so easily refuted your personal position and belief?

[Willd]

or is it just the fact that I so easily refuted your personal position and belief?

You have refuted nothing. You stated that smaller drivers move faster, and I said that in post #8. What you fail to realize, is that we are not discussing the fact that smaller drivers are able to move faster, but that what you said in post #4 is misleading. I'll quote it for you, since you have trouble remembering it.

Due to the fast response of the smaller 8" driver, they may work reasonably well with your MMGs.

Please explain this statement, I would love to hear it. It seems like to me that you are suggesting that smaller drivers are able to reproduce sound more faithfully, because they can move faster (thereby being more musical). If this is indeed what you meant, then you are incorrect.

If you meant otherwise, I am happy to hear it. This isn't about physics, because no one is arguing simple physics here. No need to act like a child.

Would the physics department of a major university be more acceptable to you?

No physics department would be able to back you up on your statement that I previously quoted in this post. Sorry.

You -- again, probably... I'll stand corrected if you actually did -- most likely utilized the work and words of others when formulating that opinion.

Of course. I'll even show you. It is informal, but informative. Read this thread, slowly. Don't miss Ed's or Kal's posts, specifically.

[Jack Gilvey]

Here's a good article on woofer speed:

http://www.adireaudio.com/Files/Tech...ooferSpeed.pdf

There's a common misconception out there that heavy woofers must be "slow", and light woofers must be "fast". If a woofer A's moving mass is higher than woofer B's, then woofer A is probably going to be sloppy, or slow and inaccurate. Can't keep up with the bass line. Woofer A simply can't respond as fast as woofer B.
There's also this concept that the "acceleration factor" (BL/Mms) is an indicator of woofer speed/transient response. High BL, combined with a low Mms, should give great transient response, right? Well, on surface these might sound like logical assumptions. However, they are in fact incorrect! More to the point, moving mass has precious little to do with woofer speed or signal response! And we'll prove it...

[soho54]

And Jack upped the ante. Anyone have counter papers?

[The13thGryphon]

If you take a look at the graphs in the article referenced by Jack Gilvey you will note that the red line (“raw” driver) and the blue line (“mass loaded” driver) do not track identically. There is, at least to my eyes, a difference in their reproduction of the input signal; more so as time passes on the graph. Even in the second graph, which is a “zoomed” view of the initial portion of the first graph, you will note that although the drivers reach their excursion peaks at the same point in time, the mass loaded driver overshoots the raw driver in amplitude by an appreciable degree. This would easily be defined as distortion. This, to me, also substantiates my position that mass does (or at least can, see below for other aspects and variables) impact a subs ability to accurately reproduce a musical signal.

“Speed”, as I term it, is not simply how “fast” a driver can react to a signal (transient), but how faithfully it decays as well. Overhang is an acoustical trait that can degrade a musical or home theater experience very substantially. Simply defined, overhang is woofer movement after the drive signal has ceased. What I’m really trying to say is that in inexpensive subwoofers in particular, where there is not likely to be tons of money spent on the cabinet, driver, and motor structure, that smaller drivers are usually better, as the higher distortion from the larger (inexpensive) drivers causes problems in terms of musical accuracy.

I will readily admit that the size of the woofer cone alone will not determine whether it can respond in a timely fashion, and then stop accurately, both in accordance with the input signal. The design (bass reflex, passive radiator, acoustic suspension, etc.) will also play a role, as will the motor structure and the rigidity of the driver.

Dynamically speaking, subwoofers experience the largest excursions and highest current levels among speakers – due to the frequencies involved. A small motor structure cannot supply the necessary magnetic field to interact with the current present in the voice-coil. A small motor assembly will therefore be less accurate than a larger and more powerful motor assembly. This is a serious impediment to both detail resolution, and power handling. A large motor structure and a rigid suspension can provide a more accurate reproduction of the musical waveform. However, when dealing with budget level subwoofers, a small motor assembly on a small, lower mass driver, will do a better job than a small motor assembly on a larger, higher mass driver.

Integration is where a smaller driver will typically outperform a larger driver. As the signal frequency rises a larger driver has a more and more difficult time integrating with the mid-bass and midrange drivers on the primary speakers. This is due to the fact that larger drivers are less able to accurately reproduce higher frequencies. There may even come a point as frequencies climb where the sub and the main driver are out of phase with one another. These problems in bass-midrange integration will result in deleterious effects… and will obviously degrade the over all presentation.

According to Talon Audio co-founder, and subwoofer designer, Tierry Budge “Although bass frequencies are slower than upper frequencies, much of what we listen to (movies and music) is very complex, with a massive amount of information and level changes occurring constantly. A slow subwoofer just cannot deal with this kind of complexity. Additionally, … speed makes it possible to keep the transients clean, fast, and dynamic, through the crossover region.”

From my reading I believe that Mr. Budge’s definition of “speed” would be the same as mine… not necessarily “faster”, but “more accurate.”

Read the following article if you’d like more information on this subject: http://www.soundstage.com/maxdb/maxdb061999.htm

[Willd]

Integration is where a smaller driver will typically outperform a larger driver. As the signal frequency rises a larger driver has a more and more difficult time integrating with the mid-bass and midrange drivers on the primary speakers. This is due to the fact that larger drivers are less able to accurately reproduce higher frequencies. There may even come a point as frequencies climb where the sub and the main driver are out of phase with one another. These problems in bass-midrange integration will result in deleterious effects… and will obviously degrade the over all presentation.

Of course....if the larger driver is not designed with "higher frequencies" in mind (or is simply a low quality drier). There are big drivers out there that can reproduce higher frequencies quite well.

What I’m really trying to say is that in inexpensive subwoofers in particular, where there is not likely to be tons of money spent on the cabinet, driver, and motor structure, that smaller drivers are usually better, as the higher distortion from the larger (inexpensive) drivers causes problems in terms of musical accuracy.

You mean, the smaller drivers are able to play higher frequencies better (80Hz+), than their cheaper/larger counterparts?

Distortion is distortion, no matter what type/size of driver it comes from, of course. A poor driver, in a poor design, will sound poor. I just wanted to clear up the whole "Since the driver is smaller, it will respond faster, therefore it will integrate with your MMGs better ( than a 10, 12, or even 15" driver would..)"

Thanks.

[ghozt]

I have a Rythmik audio servo sub paired with my MMGs and it sounds fantastic. I have analyzed my room curve on SMAART and the MMGs roll off pretty quickly around 100hz which is a little high for my taste, but the servo sub sounds good up that high and is still very responsive. I have it low passed at 110hz. Being a servo sub, it is very accurate. If the music is mixed with very little bass emphasis it will sound that way, if mixed with a big bottom end then the sub shakes the walls. This is different for me from other non servos I have had in the past where I can tweek them to output a certain db regardless of the material I am playing. I tuned my servo using pink noise at a 90db level and that is pretty loud for MMGs in my living room, as they are not a high SPL speaker. Rhythmik would be a little more than your budget and you would have to build your own box or buy one from Brian (owner of Rhythmik). I would suggest a sealed box what ever route you go, as it will respond quicker and give a flatter frequency response.

[soho54]

The13thGryphon - Re-read these sections from your article

The first thing we must know is that bass itself is not particularly fast. Virtually any woofer, even those with heavy cones can easily reproduce bass frequencies with every scintilla of speed present in that bass. So don’t buy a bunch of baloney about low-mass woofer cones leading to "high-speed bass" -- it just isn’t going to happen. If the woofer can reproduce 40Hz with low distortion, how fast the woofer starts is almost irrelevant (within reason of course). It only needs to accelerate fast enough to match the rise time of 40Hz at the fastest point along a 40Hz sine wave. If the woofer can do that, it is going as fast as it needs to in order to be as fast as fast can be -- at 40Hz. The woofer cone does not need to be able to accelerate at 20kHz velocities in order to produce instantaneous 40Hz energy and if you could build a woofer that "fast," 40Hz would sound exactly the same through a "slow" woofer.

Throw mass out.

You want the midrange driver and the woofer to integrate with sublime symmetry, with perfection and with nary a single problematic interaction throughout their overlap zone.

Use the right crossover point.

In fact, bass speed is virtually 100% a function of how ideally the midrange and woofer are integrated.

Use the right crossover point.

Yet if you measure the component electrically, there is nothing in its measurements that indicate that it is anything but perfect, speed-wise, at bass frequencies. It only takes a small loudspeaker-dependent phase shift to occur when using a particular amp to make it chameleon-like.

Use the right crossover point.

Listen to a subwoofer all by itself for a while. You won’t hear anything vaguely resembling speed coming from that slow, soggy-sounding, plodding subwoofer. It has no detail and no speed whatsoever when heard all by itself. Integrate it carefully with a nice set of main speakers, however, and suddenly the subwoofer has scads of detail, and if the integration is off a little, the bass will sound fast or slow too. All of that sense of speed and detail is coming from the main speakers, but from the midrange, not the woofer. That is why the integration of the woofer and the midrange drivers is so critical to getting a good-sounding speaker

There is that integration word again.

If you hear a system (hopefully not yours) that sounds "fast" or "slow" in the bass, enough that you have noticed anyway, that system has a problem.

True.

So there you have it, the symbiotic existence of bass and midrange, which are more tightly interwoven and interdependent that you may have thought.

Any questions?

EDIT: Also note the article is referring to fullrange loud speakers, electrostats. The principal is exactly the same, only when dealing with sub's you never reach the freq ranges alluded to in this paper. That makes integration much easier.

[Willd]

Good post Soho.

[Rythmik]

Fast bass does exist.

First, several articles refer to speed as how fast the leading edge of an impulse response is. However that is just one side of the story. A lot of times, it is also how fast it can stop (can your bass stop on a dime?). Second, the proof of the argument using an impulse reponse emphasizes too much on the high frequency components, that is, the spectral contents of the impulse is skewed towards high frequency components. That alone can explain (or I should say biased) that eventually the conclusion is it depends on the high frequency output. To explain how this can be possible, we can look at an extreme case where the impulse reponse has a bandwidth of 20khz. The impulse response has this characteristic that the energy is linearly distributed. That is half of the energy is between 0hz to 10khz and the other half is between 10khz and 20khz. But from 10khz to 20khz there is only 1 octave vs how many octaves are there from 0hz to 10khz? A step function, which has the property that the energy is constant in any octave, can show you actully the tail is the worst part for bass transducer. Conclusion, never use impulse to evaluate the bass transducer (Now you know how to differentiate a knowledgable subwoofer reviewer) . In addition, never drive a fast car without good brakes

It is not clear exactly why a lighter cone gives an impression of faster bass. One thing to note however is the lighter cone mass gives a lower "Qts". If the author of the article has looked at the tail of a step function response, it will see lower mass indeed return to zero faster and thus lead to a completely opposite conclusion. Personally I don't think this is the "only" reason for the bass to sound faster. Another factor is how easier the cone motion can be controlled in a lighter cone driver. This is all related to the ratio of motional impedance to voice coil resistance (or the ratio of back EMF to the voltage drop on the voice coil resistor and inductance). The higher the ratio, the better the control. We need good control of the cone because the vibration of the enclosure and back sound wave can return to the cone after the signal is removed. Poor control of the cone means the energy will be retransmitted from the cone. Two extreme cases of this cone control issue. Horn speakers has the highest motional impedance to voice coil resistance ratio (3x higher than direct radiator speaker). We don't hear too many complaint that horn speakers sound slow. The other extreme case is those so called pure current drive active speaker system. They have no control of the cone motion at all. They won't sound fast, that is for sure. As a matter, it only exists in academic papers.



Brian
Rythmik Audio

[Rythmik]

Originally Posted by The13thGryphon

Let's discuss a little lesson in physics...

Mass - The mass of the driver .....

Rigidity - Because a subwoofer ......

I have to say I am completely shocked by the statments made by the same article with regard to back EMF and servo control. Big motor driver has the highest back EMF, so the conclusion is smaller motor is better? And then this statement of "Servo correction, therefore, occurs on the wrong signal and has the effect of compressing transients and removing impact." We are talking about speed of EM wave traveling on copper wires (which is close to speed of light). It has less total length than an inductor. So any speaker using inductor will sound bad? Does any of our customers feel our DirectServo subwoofer has compressed output? Anyone? Acutally, the compression in some servo is caused by the limiter in the system, not the servo control itself !!

Brian

Rythmik