[Ken Stokes]

I have been reading this forum for almost a year and this my first post. I think I am just now at the point were I can discuss things with enough knowledge not to insult this group of experts! I discovered home theater about two years ago and it has become my passion! I hate to admit it but I purchased almost all the wrong components (mostly on salespersons advice) and am now rectifying the situation. I don't like to buy things twice so any advice you can give will be greatly appreciated


I'm starting to upgrade my speakers and have to choose a sub. I like the sound of both the Velodyne HGS18 and the B&W ASW4000. The Velodyne seems to have more punch while the B&W seems more musical. My system is about 50/50 ht vs. music. If I had to choose I would say music is more important as sound is only a component of a movie.


My problem is that I can't find a dealer that has both units to do an A/B comparison. Not to mention that I am in different rooms with different front end equipment.


I am going to take advantage of the Group Purchase going on so I would consider it unethical to ask to try the units at home. While my local stores are very helpful they can't compete on price and I can't bring myself to pay thousands more for the service.


I will be matching the unit with B&W speakers. I would like to get a pair of 802s but if I can't work that out I will start with 804s (I like the 804s better than the 803s).


Obviously the Velodyne is less money but that is not my major concern. If anyone has had the opportunity to do a side by side comparison of these units I would really appreciate your impressions. I am of course open to your opinions and advice.


I tried to post this on another forum and while a few HGS owners talked of their satisfaction I can't find any B&W owners or anyone who has compared the two.


Thanks for letting me in your club!


Ken Stokes


PS I am open to other suggestions but would like to keep the price under 3000. I am currently using a Denon 5600 (will be upgraded by year end) if that makes a difference.


[This message has been edited by Ken Stokes (edited February 17, 2000).]

 

[Deniz Mutlu]

Since you intend to use the 804s (two 6.5" midbass drivers) you may want to consider using a sub with smaller drivers. The M&K 350THX uses two 12" drivers which are electrically faster than a single 18" unit. This will allow the upper bass information from the sub to keep up with the bass produced from the 804s. This should also afford your greater impact in the 50hz-80hz region where much of the action takes place. It's no slouch in the deep bass catagory either. http://www.avsforum.com/ubb/smile.gif

 

[Deniz Mutlu]

Anyone else having problems with their posts not "sticking".

 

[Brian Florian]

Lsnup has brought up some important points that I'd like to expand on just a hair.


There is no dispute over the fact that the lower you go, the less you hear, and consequently it becomes a 'feel' thing. The main reason is that our hearing is less sensitive as we go low. But this does not meant those low frequencies should be ignored. In the same way that a perfect note on a violin can move us (invoke an emotion) so too can a powerful 18Hz pipe organ pedal note. The later can not only invoke an emotion, but quite literally can displace you a millimeter or two.

People tend to discount the lowest octave for two reasons: It is infrequently found in media and even less frequently found in the capability of the hardware. Although the person who started this thread is definitely shopping in the 'can-do' category, it bears noting that an 'honest' 20Hz includes not only playing the frequency but playing it at a high spl. You need allot of displacement which means allot of power which means allot of money.


I will shortly be publishing an article on Dolby Digital's LFE channel and how it specifically addresses our insensitivity to the lowest notes by extending the spl limit of the lower octaves (hardware permitting). Stay tuned.


[This message has been edited by Brian Florian (edited February 17, 2000).]

 

[Ken Stokes]

Now it gets even harder! If I grasp what is being said then Deniz and lisnup are recommending two smaller subs. This is not something I considered but the but the explanation seems very logical. Brian on the other hand seems to be endorsing the more powerful single unit.


I can tell you that the room is approximately 500 square feet with eight foot ceilings. My musical tastes, while eclectic, run to jazz and classical. I must admit that I do enjoy the punch of a large drum or deep organ.


What I wish to avoid at almost any cost is distortion. I currently have an Infinity BU2 and more often than not I turn it off. I would rather have little or no bass than the noise that this produces.


What I'm saying is that I want impact and the emotion that deep bass can give but not at the expense of clarity.


Thanks for the response, does anyone have an opinion on the models or brands mentioned. I can spend more if I have to but the more I spend on the sub the less likely I will be able to get the 802s.


Brian, am I correct in assuming that you are recommending the larger single unit?


Ken

 

[Brian Florian]

I think it is impossible for us to pigeon hole any technology approach or design as better than another especially with the incredible variety and choice that is available in the speaker market right now.


By that same token, I think its unfair to say that anyone is trying to "hide" anything. There are advantages to both multiple small, single large, and tiny (with insane excursion) driver designs, and there are excellent implementations available to all.


To do a little quick math, and try to level this, two 12" drivers will collectively have a hair under 900sq.in. of surface. A single 18" will have 1020sq.in. This means that by definition, all thing being equal, the two 12s must move further than the 18 to move the same volume of air. I'm not knocking the M&Ks, they rock. The added challenge presented by an enormous driver is that it needs allot of power, and allot of control. Both of these needs are in principal met by the HGS-18's design, a model mentioned at the beginning of this thread, by its servo feedback and insane digital amplifier.


It could be argued that if multiple drivers is your game, then a pair of HGS-18s could be the ultimate BUT...


For the layperson in the average home theater, multiple subwoofers have a few significant drawbacks that the studios don't. Decor and physical space is one. Getting it right is another, possibly more important here. It is so easy to poorly place a pair of subs (you can halve the performance if not done right) that it is often recommended that two simply be stacked. In fact, several of the reviews I've read on the M&K units end up with exactly that configuration. Then we are back to the decor (just try selling your wife on the idea of a tower of subwoofers http://www.avsforum.com/ubb/smile.gif )


These are all very interesting and valid points I see in this thread but I think there is no easy answer for the original poster. All the subwoofers mentioned have good reputations.

 

[TV]




>>>Please remember that playing low and loud is great, but the average human cannot truely hear a 20hz frequency. You can only feel it.<<<



How should this affect the performance goals one sets for their HT system?


>>> My MK350THX with a 25HZ test frequency will play at 118DB in my HT room.<<<



Either you live in a coffin,the SPLs included a TON of distortion,or you used some wierd mic placement(like 1/2" from cones?)



WSR included the flagship MK unit(the 5000) in a recent subwoofer shootout. The big 5000 maxxed out at 106dB/25hz.




>>>, but most people are looking for that 40 to 70HZ whaloop that they can actually hear and feel.<<<



Well, I'd guess it to be alittle lower...maybe 32-55hz...but I agree in principle.


>>>The lower waves are very long~ ~ ~. A 20 hz wave needs almost 40feet to complete a full cycle. Lets face the facts that most people dont have a 40 foot long or wide room.<<<



The smaller the room, the lower the subwoofer will extend, and the louder it will play in the lowest frequencies. This is a function of *room gain*. The larger the room, the smoother the bass will be(typically)...due to the higher density of modes.





>>>Lets say a HGS18 will produce 118DB at 50HZ and a HGS10 will produce 115DB at 50HZ.<<<



I understand the concept...but i think it would be better to use 25hz as an example. Almost any subwoofer can play >50hz reasonably loud/clean.



>>> Yes the 18 is louder, but if I used 2 HGS10's the spl would be around a 6DB gain over 1. The typical response would now be 121DB.<<<



Well, I'm not entirely sure how you got the *121* figure? regardless...at 25hz(where it's more meaningful)...a single HGS18 would walk all over a pair of HGS10s.



Again, I understand the concept....maybe I'm just nitpicking the poor example.


TV

 

[TV]



>>>I am surprised that no one has yet mentioned the Paradigm Reference Servo 15. It compares very favorably in audible performance to the Velodyne Servos. From what I have read, it is not as accurate at the lowest limit,but outputs @ -2or -3 dB compared to the Velo HGS 18 and the difference in THD is inaudible.<<<



I think the HGS18 would have at least 6-7dBs of headroom over the servo15. Of course, the HGS18 is a KILLER too. So being within 6-7dBs of it really speaks highly of a $1200-$1300(street) subwoofer.


TV

 

[Ken Stokes]

Thanks to everyone who responded, it is greatly appreciated!


While two subs is intriguing it sounds like there is room for error in placement and I can't even begin to think of how my wife would respond to two units.


Since no one advised the ASW4000 over the HGS18 I would assume that is an endorsement of the Velodyne.


My only other question is am I ok placing this unit in a corner. It will be between a wall and a cabinet with about seven inches of total clear space. There will be nothing in front of it.


Thanks again.


Ken

 

[Brian Florian]

triff is right, we kinda got off into the theoretical and away from practical.


I have seen scant few instances where a corner was not the best spot for a sub. The only reason not to would be if a particular frequency band really gets boosted and makes the sub sound 'fat', like a camera slightly out of focus. And even when this was the case, the sub usually ends up in the corner not just for aesthetics but because it is the most 'efficient. IE the sub will have to work the least for a given output.


A few years ago I was helping my nephew pick out what was admittedly a modest sub. He was so excited when we got to his home, he wired it up and everyone stared in disbelief as the little sub, dialed to the max, was doing virtualy nothing in the middle of the room. He was disappointed.


A little later he was playing on the PlayStation with some music in the back ground. I quietly slid the sub into a corner. Instantly he and his friend spun around and asked "What did you do? It sounds awesome!".

 

[Ken Stokes]

OK, one last question. How many of you guys are engineers? I have been reading every HT forum I could find on the web and the knowledge here is unbelievable! Much of what is said is beyond me but I'm actually trying to research much of it. I wish I had the same curiosity years ago when I was in college!


I'm a manufacturers representative (salesman) and every time we introduce a new product we listen to hours of information from designers and engineers. Without exception I come away with ten to fifteen minutes of information that I can spin into a story and sell the product with. Sorry to digress so far but as I reread all of these posts I started to laugh out loud because I feel like I just left one of those meetings!


I really appreciate the advice and I hope you guys don't mind me hanging around, I think your all great!


Ken

 

[TV]



lisnup sez...



>>>Corner placement is not always ideal!!<<<



That's true, there are always exceptions...however rare.



>>> If you are looking for more spl from a sub that is unable to acheive naturally then corner loading is recommended due to the fact that it can increase SPL by at least 3 to 6 DB. With a large sub like the Velo HGS18 thier should be no need for this unless your room is quite (really) large.<<<


Even a big HGS18 can benefit from corner reinforcement---in a typically sized room,a single HGS18 is going to be straining to hit reference levels anyway---why handicap it even more by not locating it in a corner?



>>> Corner loading creates standings waves and it excites resonance modes, produceing a "muddy or boomy" sound.<<<



Uh...no.


Room modes or *resonance modes* or a function of the rooms dimensions. You cannot *create* them by locating a subwoofer in a particular spot. The modes are either there, or they are not.


Along with reinforcing the output, corner placement excites the maximum possible number of these room modes. This leads to the smoothest/loudest/cleanest bass over a variety of listening positions.


The major problem with room-modes in the bass region, is that there's simply not enough of them. Therefore, even eciting the maximum number of the *modes* could still result in uneven response at a given listening position.Corners work best, perferably a corner without adjacent boundaries.



>>>Try hooking the sub up and placeing it where you would normally sit. Remove the furniture from the room then play a CD, or other source material that has plenty of bass material that you know well.<<<



The old *aocustical inversion* trick.


This CAN work ...but why would you want to remove the furniture? It's going to be there later...why add a variable?



For this to work well, you need a test CD (or signal generator). Without checking a wide variety of frequecies(maybe 1/3 bands--20/25/31/40/50/63)...you'll just be guessing as to what location will be smoothest with ALL source material.


I've tried this *trick* in 3 different rooms, using a variety of seating positions --- the subwoofer ended up in or very near a corner each time anyway.


TV

 

[avdoc]

Very well said. The only thing I would add is that some "bassheads" prefer high distortion in the bass region, especially for movie soundtracks. Thus accuracy is sacrificed for the sake of more oomph. I don't subscribe to this philosophy, but some do. Also, I think at lower price points the way to get high SPLs is to rely on distortion. However, since we are talking about subs &gt;$1000, there's no reason to sacrifice accuracy for bass. So basically I would agree with your statement completely provided we make the assumption we are talking about high-end subwoofers.