SVS CS Ultra vs. Velo HGS-18 vs. Revel B15 (1 Viewer)

[John Doran]

can anyone assist me in making a decision between these three subs?

i probably don't need to mention that the criteria are depth, speed, depth, clarity, speed, clarity and depth. all at reference level.

thanks.

 

[John Sturge]

It seems that you want deeeeeeep bass. So I would go with the SVS CS Ultra subwoofer. However, Revel B15 kick's ass for music. Get the Revel B15 subwoofer for music, it is quite worth it. HGS-18 is not as deep as the Ultra, but the bass is clearer. Sorry guys, but I cannot see myself using my SVS for music, just for movies. Too much bass, can ruin music.
You know what the new Powered Cylindewrs need Ron!? Servo's! Bigger amp, 2 parametric equalizers, and a servo in one subwoofer!
I must be crazy....

 

[Dan Hine]

Sorry guys, but I cannot see myself using my SVS for music, just for movies. Too much bass, can ruin music.

If one has their system calibrated correctly then how would there be too much bass for music? Would it not be equal, relative to how the music track was mixed? From all the positive feedback from SVS owners saying they work wonderfully for music, I would think that is the case. For the record, no I do not own an SVS. But I think there is significant evidence that points to SVS working great for both applications.

Dan Hine

 

[John Sturge]

For the record, no I do not own an SVS.

Why should I care about your reply then? We don't need a flame war though. My SVS 20-39 PC is properly calibrated.

We all have different opinions on bass and sound.

 

[Dan Hine]

Ouch...John, that was kind of harsh. I put that comment in so it would be obvious that I wasn't someone with an SVS and therefore potentially biased towards my purchase. Also, I did not know you owned an SVS so how was I to know that you had any first hand experience yourself?
Additionally, I do not think my comments were phrased in a way to "call you out" so to speak. I phrased them as questions. I had my take on the situation and wanted other people's input on it as well. I did not reply to be insulted. I come to this forum to learn and the best way to learn is to have discussion, not arguments. Sorry if I offended you. :frowning:
Dan Hine

 

[Steven Simon]

Come on now, play nice guys......

 

[Bhagi Katbamna]

Dan is absolutely correct. If a subwoofer is calibrated/equalized properly and is good for hometheater, then it is good for music. They don't have little dwarfs in them saying "I hear music, time to mess this sub up." All joking aside, the sub doesn't know you are playing music or a movie.

 

[Tom Grooms]

HGS-18 is not as deep as the Ultra, but the bass is clearer

Do you have any published data to back up this claim? I don't doubt it, I just haven't seen the numbers on the Ultra. I have personally measured output down to 12 Hz from a HGS 18

And what is clearer ? ? ?

T.G.

 

[ling_w]

A good HT sub does not necessarily means it is a good music sub. Even with a HT sub that has been properly set up, the sound coming out of the LFE channel is distinct and usually has no correlation with what are coming out from the mains. For example, when a explosion occurs in the soundtrack, the LFE usually contains the rumbling, while the main/center and/or surround speakers would play the upper freq of the explosion. These were seperate pieces of sound created in the studio and mixed together to sound like one event, but it is still two distinct event. And who is to say that is how it really sounds like. When the low freq is phase delayed by 1 or 2 wavelength, do we even know that it is happening with the kind of source that is being played? You could have the most delicate electrostatic speaker for the mains, and a honking horn sub. As long as those two are playing distinct tracks where there is no actual correlation between the two, there would be no mismatch noticed.

But with music, a instrument could easily play notes where the overtones cross over from the sub to the mains. Plus when the instrument is moving up or down the scale, the fundamental could easily move from the sub to the main and vice versa. Our experience with how these instruments should sound in the real world tells us if this is the reproduced instrument sounds right. The bass attack of many instruments along with its overtones has to arrive at our ear at the same time, or else we would detect that there is something wrong with the playback.

So as you see, a good HT sub setup might not mean it is good for music, and a good music sub does not mean it will be adaquate for HT.

If you are looking for subs that has speed, you would need to get one of those subs where it is operating below its resonance freq and is equalized until it is flat. But since it is heavily equalized at low freq, it will never hit 121dB/3m @ 15hz. A couple of examples on these subs would be the Bags End and Vandersteens.

To achieve reference level & depth, you probably would have to utilize multiple subs of the same make. To achieve speed and clarity, you would have to start off with subs that are good for music. Stacking up X musical subs might give you speed, clarity, depth and reference level, but stacking up Y HT subs might give you depth and reference level, but you would never achieve speed and clarity.

 

[Tom Grooms]

But with music, a instrument could easily play notes where the overtones cross over from the sub to the mains. Plus when the instrument is moving up or down the scale, the fundamental could easily move from the sub to the main and vice versa. Our experience with how these instruments should sound in the real world tells us if this is the reproduced instrument sounds right. The bass attack of many instruments along with its overtones has to arrive at our ear at the same time, or else we would detect that there is something wrong with the playback.

Again, I'm confused. What does this have to do with subwoofer construction? (assuming music sub's differ from HT subs)

A good subwoofer, properly calibrated, should only be noticed if you turn it off.

$0.02

 

[JohnHN]

Do you have any published data to back up this claim? I don't doubt it, I just haven't seen the numbers on the Ultra. I have personally measured output down to 12 Hz from a HGS 18

The following may be of interest
Link Removed

 

[John Doran]

tom,

i think ling's point is that it's not the SUB that matters, but US - you're right the sub doesn't know what it's playing, but WE do.

as ling pointed out, since we have no real-world reference as to what actual explosions and other transient lfe effects sound like (even if we were demolitions and firearms experts, maybe human hearing just isn't capable of resolving a lot of the sonic detail in explosions and gunshots...), as long as the sub is reasonably quick, it'll sound great to us.

but, we all have a pretty good idea as to what musical instruments sound like, since we have all undoubtedly heard many good live examples that we use as benchmarks when we listen to recorded music (whether we know we're using them as benchmarks or not). so, it is entirely possible that a sub that has been firing out what we ASSUME are good explosions will not be able faithfully to reproduce the bass that is generated by musical instruments. (even if we DON'T have experience with a particualr instrument, ling's point is that a sub's inability to integrate the low-end of a musical note with the mids and highs is inherently more noticeable with musical notes than explosions. i think he's probably right).

but your point is a good one, tom, and ling's observations do nothing to contradict it, since, if ling is right, it's NOT as if a musically "poor" sub is actually doing a good job of HT - it's just that we think it is precisely because we don't have a good non-HT reference for transient lfe effects - if we did know what those lfe effects were supposed to sound like in the same way we know what musical instruments are supposed to sound like, then we'd presumably notice that the same non-musical sub wasn't doing such a good job with HT, either.

have i got this right?

 

[Craig Morris]

John, I have no experience with the SVS or the Velo, but I will say that the EQ and the Low Frequency Optimizer software are amazing on the Revel. I had 15-20 dB variations in my bass response between 20 and 100Hz. According to the computer model, it should now be closer to plus or minus 3 dB with the EQ settings.

It certainly sounds great.

 

[ling_w]

Again, I'm confused. What does this have to do with subwoofer construction? (assuming music sub's differ from HT subs)

HT subs frequently requires headroom and headroom and nothing else. So frequently, a ported design is used, which has wildly varying phase delays throughout its frequency range, with increasing time delay as you approach the port tuning freq. This would cause a instrument's fundamental tone to arrive at the listener after the overtones, which is not how live instrument sounds.

As to movie soundtracks, who is to say that they know what it sounds like to have a car you are in blow up? Even the guy doing the effect mixing don't know what it really should sound like. They might just mix it so that it sounds good to him. Plus, they would mix the LFE seperately from the main explosion, adding some 30-50hz rumble to the LFE track for good measures.

If you are a demolition expert, you would probably laugh at those sound effects. It's like the gunshot effects in the movies, where it always sounds so loud and explosive. But everytime you hear interviews of crime scene witnesses, you always hear them talk about hearing firecrackers.

If you plot a combined LFE & mains signal during an effect scene, it might not mesh seamlessly like the way a musical instrument's plot.

 

[Tom Grooms]

As to movie soundtracks, who is to say that they know what it sounds like to have a car you are in blow up? Even the guy doing the effect mixing don't know what it really should sound like. They might just mix it so that it sounds good to him. Plus, they would mix the LFE seperately from the main explosion, adding some 30-50hz rumble to the LFE track for good measures.

This all seems irrelevant. How a car explosion sounds doesn't matter. Gun shots, Who cares. All a sub can do is playback the recorded material. That's what we are talking about right, the sub's ability to faithfully replay the source material?
Bottom line: If your telling me that your HT subwoofer doesnt do a good job at replaying music, than you need to purchase a better sub.
$0.02

 

[ling_w]

This all seems irrelevant. How a car explosion sounds doesn't matter. Gun shots, Who cares. All a sub can do is playback the recorded material. That's what we are talking about right, the sub's ability to faithfully replay the source material?

That is the difference between music and soundtrack. you want the sub to faithfully reproduce the source material, and in the movie soundtrack world, the source is completely artificial, with no real world correlation. It is made to sound impressive.

Music, on the other hand, has a real world reference, so you can judge how the recording sound in reference to live versions that you have heard in the past. Unless it is a 100% synthesized music, then it comes down to how impressive the sound is.

 

[Tom Grooms]

I think your missing my point.

Why cant a sub that can produce 121dB/3m @ 20hz sound good in a 2 channel music only system?

Truly great subs reproduce the source material, whether it be a car explosion or an octa-contra bass clarinet.

 

[Tom Vodhanel]

>>>HT subs frequently requires headroom and headroom and nothing else. So frequently, a ported design is used, which has wildly varying phase delays throughout its frequency range,> with increasing time delay as you approach the port tuning freq. This would cause a instrument's fundamental tone to arrive at the listener after the overtones, which is not how live instrument sounds

 

[Alex F.]

As Ling indicated, the performance requirements for a "musical" sub and one intended primarily for HT are often quite different. There are many parameters that can make subs sound very different from one another. I favor subs that are very tight (a low "Q") and closely follow a musical bass line, versus a typical HT sub that has a higher "Q" and may blur transients a bit. The musical sub may go very deep and play very loud but its much-sought-after "tightness" might result in it having somewhat less of that "punch in the chest" of a HT sub.

Very few subs are reference-quality performers in both categories.

Not having heard one, I do not know how tight (i.e., musical) the reproduction is of an SVS sub.

I have one question for Tom: Are SVS subs tuned for a low, middle, or high "Q" (what is the approximate numerical Q value)?

 

[Kerry Hackney]

I certainly am not an expert sub designer, but I do have a competitive sub. In my case the in room response is relatively flat but not capable of 120+db @ 20hz/3m. That said, I rarely listen to movies at the so-called reference level anyway. My sub is ported with a Q of .577 I am curious to know how you hear "quickness" if the response is flattened through EQ or room size/positioning particularly in the lowest two octaves?

In "typical" high Q designs for "home theater" aren't the subs normally ported with a Q greater than .7? If that is the case, then the natural response of the unit is not going to be flat. It will have crest that peaks at the tuning frequency and then falls off rapidly below it. This tends to accent the frequencies from 20 to 40 for movie effects. But the premise put forth by Tom and others is that "if" a given sub has flat response and is well calibrated it should sound fine on movies and music. I think musicality has a lot more to do with flatness than with group delay or Q.

In the case of SVS and many other popular designs, I don't think their Q is above .7 anyway. I am betting that most are over damped with high power supplies. As for low Q designs not having any "punch" I am not sure I understand. Are you saying they are too flat in response for HT? If so, how is flat bad?