Raider

I have heard this explained before, but since it didn't take, I think I may not have really understood it. :| A concise layman's definition, as much as possible, would be appreciated. As with so many other things, what variables affect group delay? Is it primarily influenced by enclosure design, or do room acoustics come into play? What are the tradeoffs? What is considered optimum, and what does it sound like when it is optimized, or when it is compromised? What enclosure types optimize it, and which types tend to compromise it? Thanks.

Wow. Great posts folks. Refreshing to see such a constructive debate. Thanks for sharing.

I hope it comes on line faster than SED has... ;(

I have, but I have decided that I can't fit them in my budget - along with the dining room suit that would be needed to go with 'em. Actually, the wife's encouraging me do do what I want to do. I thought about Fish's RF83/RC64 as he's just up the road about 5 hours, but she prefers something in black, so with this kind of support, why not get what we both want.

Coming soon to a (home) theatre near you, a heart warming story of a boy, his dog, and infrasonic bass....

The salesman told me that he deliberately left the setup on an entry level receiver, reasoning that if someone had a receiver like it, they would know the Klipsch's would sound as good for them, and that it was really the speakers making the difference. And if a customer had better electronics, they would be very confident that the Klipsc's would sound ever better on their home system. I know this; they sure did the Sony proud.

DrWho: Reading between the lines here, wwould it be true that a sealed sub seems to have fewer tradeoffs and is easier to tune to the room, generally speaking? Also, WinSD makes my Mac sneeze. Any similar programs that will run on a Mac? I can run WinSD on my MacMini, but I'd have to buy a copy of XP and run Boot Camp. Alot of money and trouble for one utility.

rmlowz over on the "Danley Labs DTS20 on the Way" thread had a Trinity that he let go. He may be able to give some more subjective analysis....

Attached (I hope) is a crude drawing, not to exact scale, of the bonus room where I will be placing an HT system. The room is about 16.5 by 16.5 feet, though 2/3 of the wall adjacent to the stairs going down to the kitchen is an open banister and the stairwell effectively adds 3' to that dimension. A hallway continues off of the stairs and opens on the other end into a two story stairway and foyer. Parallel to the stairs off the bonus room, a ridge runs the center of the room where the peak of the ceiling at 10' runs the length of the room. The ceiling tapers to 8' at the wall adjacent to the attic. The walk-in attic runs the length of the room behind the wall opposite the stairs. The wall opposite the closets is about 2/3's windows from about a foot off the floor up to eight feet. My question is this. What would be more likely the best acoustic orientation for the room. Should the TV be placed along the wall that is backed by the attic? Or should it be placed on the wall between the stairs and the attic? What acoustic recommendations would you make? I had planned to use some owens-corning 703 panels I would make. I have also considered some sort of bass trap/ diffusor at the peak of the ceiling. Any recommendations are appreciated. Thanks Raider

If I were you I'd get rid of all the clutter you have laying around, save for a couple years then spend 100k+ on a dream theater (or listening room) and dump "subs" as a spending habit. By the way...I can bench press 315lbs without breaking a sweat. Grow up a little. Yeah, yeah, but can you clean and jerk kramskoi's twin TC3000 sub?

What SV subs would be the closest peer? What other subs, if any, would offer autocalibration and similar output and extension?

kramskoi: I have saw post on TCSounds forum, but didn't realize it was you. Coupla questions. Is the enclosure CNC cut? Would two enclosures at half the volume perform as well. Two 100 lb. enclosures might be a little more manageable. Raider

Both have the same tweeter, so the high end will be the same, but they use different bass drivers. Not a huge difference between the two, but any two drivers will have a slightly different sonic character, especially of different sizes. Compare to two to each other, nothing else playing and you'll see what I mean. Another difference would be in the output capability of the larger drivers, which will be more similar to the mains you have chosen. So side to side pans across the front stage will be more seamless and convincing. Most folks here recommend getting the best center you can. FWIW

I realize that I'm preaching to the choir here, but wanted to convey an experience that some here may have had, but which I hope most here haven't had to go through. A few weeks ago I had opportunity to visit a local dealer about an hour from here, and was allowed by their courtesy to audition a Reference setup for about an hour and a half, using CD's that I am very familiar with. I have listened to these CD's probably a hundred times each, and also used them to tune and tweak several high-end high sound quality vehicles over the years. In addition, I know some of the artists from work I did here in Nashville, so I can quickly identify coloration of their voice in the response of a speaker. The 5.1 system consisted of a pair of RF82's and an RC62 for the front stage, a pair of RS62's in the rear, and an RT-12d in the front left corner of the room, and its ARC capability had been used to tune it to the room. The system was being driven by a Sony entry-mid level receiver, not an ES, so I think it was representative of electronics that would be commonly found, and would be probably on the low side of the spectrum of electronics quality that would be typically used to drive a Klipsch system. The listening room was essentially a room that had been partitioned off in a warehouse but furnished as a typical HT room would be. But it was large - about 18 by 30 feet with open door ways on both ends into much larger rooms. The only sound treatment in the room was thick velvet curtains on the wall behind the front stage. This was probably a more hostile acoustic environment than what would be found in most homes. While I was already favorably impressed by auditions of Klipsch speakers at other dealers, I was more focused on selecting from among the floorstanders in the reference line, and used a single CD, replaying the same few cuts for comparison. For the next hour and a half though, I was in sonic bliss. It would have been one thing if I had heard improvement in one of two cuts as is often the case when comparing speakers. But I didn't expect to find previously missing material in almost every cut of almost every CD. Often in complex passages, a familiar sound in a complex passage would reveal there were actually two, three, or even four different instruments or voices. Further the sound stage was deep and well defined, and seemingly in the room with you. In most every song, the Klipsch's dissappeared, and I found myself enjoying nuance in instruments, resonance in the body of guitars, timbre in brass instruments, and being able to easily hear when the resonance changes between the head and the chest of a vocalist as they move up and down the octaves. I enjoyed the performer and the performance itself; I didn't hear a speaker trying to reproduce a performance. I found this to be true, no matter what genre I played whether rock (ZZ Top), Opera ( Andre Pocelli to my wife's delight), Country (Faith Hill), metal (POD), or contemporary Christian (Whiteheart, Susan Ashton, Out of the Grey, and Gary Chapman), or even big band/swing. At one point when the saleman and I were talking, I actually thought someone walked past the door singing, so realistic was the imaging and soundstage. I had frankly become pretty jaded toward audio having heard a lot of high end equipment that sometimes impressed, but usually didn't. It was often different, often better in some way. But on this occasion the Klipsch impressed me by essentially dissappearing into the music. The engineer in me began to analyze (sorry can't help it) why this was happening. Of course the directionality of the horns and the associated ability to minimize acoustic refraction and reflection was a large factor. But the more I listened, the more I think the greatest contributor was the dynamic range, or headroom. Though I had experience with Klipsch in the mid-late seventies, they were way out of my price range then, so over time I migrated to more conventional direct radiators, beginning with Advent, EPI, and JBL as the standard bearers. Over the years I had experience with many different speakers, and over several years I focused on high end car audio, as most of my available listening time was spent in a car. But after kids, we began desiring an HT room where we could enjoy TV and movies. I have renewed interest in home audio, and am also slowly assembling an office studio where my kids can enjoy the creativity of music, and Garageband on my mac. The availability of increasingly cheap power has to some degree driven the current audio landscape. Most folks seeking high end find a speaker they like, and throw as much power as they can afford at it, hoping there will be enough power to drive the speaker to realistic levels within the headroom of the amp. Or they chose a very small speaker for its visual aesthetic and think that a more powerful amp will overcome its size somehow. But even with the shrinking cost of power, amps capable of the kind of power required are still often out of the typical HT budget range. If you give away up to 10 db of headroom in your speaker selection, this approach seldom becomes practical, or achievable, at least for most folks I have found. From a physics standpoint throwing more power at a driver that is already fast approaching its mechanical limits only increases the heat soak of the voice coil, and increases distortion, usually at an exponential rate. With the dynamic peaks in music often 10 times that of the average signal, preserving as much headroom in both the speaker and the amplifier as possible becomes more and more important to realistic reproduction. The 6-10 db increase in efficiency offered by Klipsch over its peer competitors in most cases, puts usable headroom within the reach of the power offered by most any mainstream amp or receiver. So while my right brain was enjoying my favorite music as for the first time, my left brain was busy realizing that over time I had been robbed of dynamic range. I searched for what I had heard in Klipsch years ago among direct radiators across the years. And I realized I had been slowly robbed of the dynamics necessary - necessary - for realistic sound reproduction. Kudo's to Klipsch engineering and product development for the great job they have done on the Reference line. They have allowed the intrinsic benefits of the horn philosophy to be much more easily attained by those who love music. For those who can take the experience to the next level with the Heritage line, all I can say is - enjoy. I came away from this experience knowing with absolute certainty that Klipsch will be the next speakers in my house, Lord willing. And likely the last. Because I had forgotten that it really isn't so much about the equipment. Its really all about the music. This especially became apparent to me after I was playing my wife's favorite Andre Pocelli cut. The song ended, and my wife turned her head, and looked in my eyes with an expression that said " We've got to have this". And that pretty much said it all. Just my opinion, for what its worth.

I think you will be thrilled with the selection you have made over what you currently have. As silversport notes, hold off on your new receiver for a while. The increase in relative efficiency between what you have now and the Klipsch will be the same as if your current receiver put out 4 times the power. I have been looking at a similar setup. You may want to consider a couple of things. First, i would try to timbre match your front stage if at all possible. The center speaker is very important as a majority of HT material is mixed to that location. So I think it would be wise to go to the RC62 if possible to match the RF62's. Second, if you are floor mounting your surrounds, consider that the RB61's -by the time you buy stands- will likely cost the same and occupy the same footprint on the floor as a floorstanding model. you may be able to get another pair of RF62's for the same price. And you will increase the bass response capability of the total system as well. This could likely be done with the money you will save from probably not having to buy another receiver. Let us know how things turn out for you.

Arthur Let me try to answer that. I needed to set the Revel sub to +12db and the ultra mains to -7db on my receiver to make the explosion of the Keep wall in LOTR sound the way I thought it should. To really rumble. Is this because of the high efficiency of the ultras? Still, I don't know if I am getting that feel it in the chest impact so many reviewers talk about. I do feel some vibration in my chair. Another thing I need to know is how do you know when you are driving a sub to hard. Should that be a concern? I don't think I am near that yet but how do you know? Tom Not good.The B15 is not enough sub for your needs.My mains are at 0dB,center at -3dB,sourrounds at -4dB and subs at -12dB and not even half way on the units! And the bass is simply THERE when called upon. You need to try two THX subs,these will best the B15 by a solid 10-12dB down deep.If this is still not to your liking,you know TC Sounds has a super sub composed of two cabinets and two Crown amps capable of filling all rooms except stadiums($7000). I would get a much more capable subwoofer(s).Start by giving the Klipsch THX a spin in your house. I would love to. It is only the $$$ stopping me. THX's two subs and amp don't come cheap. I would have to win the lottery to go the TC Sounds & Crown route. In my most recent post I was just saying that for the time being I could acheive better results in the smaller room without breaking the bank. It could be the place to go for movies and serious music listening and the great room fo regular tv, sports, chick flicks and etc. On the other hand it does seem a waste to under use those thx fronts center and surrounds that way. They deserve better. A solid 10-12 db down deep huh. Will that be enough? I guess it is obvious I am undecided what to do really. with the THX pair you're going to get a fair amount of output but you won't get the extension that really brings out DVD's like WOTW...with more selections encoding infrasonics, you need not only massive output but excellent extension also...the THX pair is probably tuned too high for this, and the 4th order roll off won't help either... a nice high-end 2x15 (or 2 units) sealed that is allowed to rolloff at 6 dB/ octave "and" keep massive midbass output is the ticket here...you should strive to couple the sub to the room and maximize extension...if you think below 16 Hz does'nt matter i can email you spectrals of various movie clips to prove otherwise...i guarantee you that a tc-3000/lms-5400 based dual 15" like the one i built would impress in that small room...with a Qtc. of .450...the attack is violent and the decay rapid...almost an infinite baffle sound signature and in a 6 cu. ft. enclosure, which is quite a small footprint for a 2x15" subwoofer...the lightning,pods and especially the laser scene in WOTW produces absolutely visceral impact and NO FLAB...i sincerely doubt that you could get 105 dB @ 12 Hz (5% 3rdHD) at 3.5 meters from a pair of THX 12" subs... The problem with the vented subs is the 4th order rolloff, with it's consequent group delay and unloading issues...if a high pass is used, this become much worse (5th or 6th order in some cases)...rapid rolloff, increased impulse response, ringing...i.e. transient response...you have to protect the driver (from unloading) below the tuning point, so this is mandatory for commercial vented subs... The problem with sealed is worse...you won't find too many sealed subs without a high pass filter installed...for instance the Pardigm servo15 rolls of at 20 dB octave because of it's filtering and has nothing to offer as far as true infrasonic output...don't make the mistake of equating output with extension...two different animals entirely. kramskoi: What TC set up are you using? Which drivers, amp, enclosure size and porting? Thanks

Before I pull the trigger on an RT10d or RT12d I wanted to make sure that they represent a solid value among their peer competitors. Opinions from those with the experience and/or knowledge is appreciated. Let me ask the question two ways. First, how do these subs compare with other products at the same price points in regard to output, sound quality and extension? Second, are there any subs that equal these in terms of output, sound quality, and extension, but at a lower price point? DIY designs you have actually built would be of interest as well, but please be specific as far as driver, enclosure size and type, porting, amp used, DSP used, etc.... Just trrying to get the "pecking order" established in my mind, but I haven't had a lot of experience with home subs. Thanks for any contributions.

Yeah, I agree. You guys should get rid of some of the clutter and simplify your life. It really can be an addiction. I know of a charity that will be glad to receive your surplus equipment and it will be tax deductible. Please send surplus equipment to: Raider Foundation for the Infrasonically Challenged. I'll also be glad to be your sponsor, when you come to grips with your situation .

I understand toeing in the speakers, but can't understand what is meant by the above statement. You could imagine or draw a line of the average angle of the side of the tweeter horn. The speaker would be placed or toed in so that this line would be parallel to the wall the speaker is closest to.

I'll take that as advocacy. Do you know if this Is this true for the entire Klipsch line or just specific models?

HiFi Buys in Nashville, TN. Salesman is Paul Borasky. This is an independent store, NOT part of a chain of stores elsewhere under the same name. The Nashville store's use of the name predates the chain by several years. I have bought gear from them off and on for about 25 years. Highly recommended and worth the drive if you are in the middle Tennessee and southern Kentucky area. They have been very patient and helpful on several different occasions in helping me narrow down my selection within the Reference line. as a bonus they are very competitive in pricing.

For those who have heard both what difference is there between these two subs. I would think that the Adaptive Room Correction would effectively negate any difference in frequency response. So is there any difference in the sound character or voicing between the two? Any advantage of one over the other? Or is it just a matter of how much output you need for your room size?

This'll be interesting. I take it that the D-8 uses passive radiators like Sunfires typically do. So the execution by the two different manufacturers will make for an interesting comparison. By the way, something I have often wondered about. I have heard it said that passive radiators behave very similarly to ports, but don't have the problem of port noise. It would seem to me that the passives also effectively multiply the surface area and displacement of the primary driver for a given motor movement and that the passive solution should increase the output of the speaker more so than porting. Is this true, even if the port is large in diameter? Is there a tradeoff (of course there is; this is speakers we are talking about) involved where you reach a point in adding passive surface area beyond which it is more advantageous to add another active driver for a given volume enclosure? I have been very impressed with the RT12-d I have listened to, with its only disadvantage for me being the cost which will be a stretch. I'm also trying to decide if I would be happier with two lesser subs at the same net cost. I would be using these with Reference floorstanders so response below about 50 hz is the main concern. I would be interested in your opinion also, given your expereince with several, to know what subs you consider to be peer subs with the RT12-d as far as sound quality and output. At the RT 's price point, are there better alternatives? A similar question would be are there any subs at a lower price point that have similar performance. I am leaning toward an RT sub at this point, and will listen to one more tomorrow, but my experience with home audio subs is limited, and I was just curious as to what relative value the RT represents in the market. Thanks for any input and opinion.

Not a problem. As I said, "Its interesting how language, divorced from vocal inflection, facial expression, and body language can so easily be misunderstood." And often humor is the most difficult convey. Sorry I missed the queue. I look forward to learning more from your posts. It's rare to find anyone with as broad an actual experience base with as many subs, even a dealer.

A few weeks ago I was auditioning a pair of RF62's and remarked to the salesman that I really liked the Klipsch speakers I had heard, but had noticed that they didn't seem to image as well as some other speakers. He said "Wait a minute", and proceeded to toe in the speakers at nearly 45 degrees (they had been pointing pretty much straight forward). He said that he had heard Paul Klipsch speak at the store several years earlier, and that something Klipsch felt strongly about was that the speaker be placed so that the side of the horn closest to the wall be parallel to it. Indeed, the image locked in and was rock solid, and well defined after he finished. He went on to say that this orientation took advantage of the horn's directionality and eliminated most unwanted reflection off of the side wall, along with its detrimental effect on imaging. In thinking about it, this is pretty much the way the horns are oriented in a Klipshorn. i certainly couldn't argue with the results, and will likely use this as at least a starting point to orient any Klipsch speakers I buy. But I am curious as to whether or not Mr. Klipsch was known to feel strongly about this orientation.