RF-15 system with what sub?

[Groovie]

[om13934]

So then you're saying that having the crossover at 80hz works, not only for the RF15's but for the center and surrounds too? I don't think my center sounds very clean with the crossover at 80, but maybe you have a setting for large, medium, and small speakers with your receiver and two crossovers for small and medium sized speakers.

[Groovie]

My surrounds are rated as low as 50hz, and the center channel is mainly for vocals, plus the rc-25 can handle -80hz, I have not singled the speakers out and listened to the crossover individually, but again the only speaker that would take issue with the 80hz crossover is the center channel and you really should not be concerned with deep bass on that channel, your mains will pick up anything the center lacks. And no my receiver does not have a medium speaker setting, or two crossovers.

What works on my system may not work for you, it is up to your individual taste, and it sounds as if an 80hz crossover is just not your cup of tea.

[Groovie]

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On 2/18/2004 1:23:32 PM nicholtl wrote:

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On 2/17/2004 9:34:55 PM Groovie wrote:

I am sticking with the 80 hz since it is the THX recommended cross over and the speakers have no issue with it.

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Just so you know, it's only THX recommended assuming you have a full THX setup. But that said, 80hz does work for many people.

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For some reason my previous responce to this post did not post...

Nicholtl, I would like to know what you beleive you are talking about in this post, what is the basis of your comment? You truely believe a THX recommendation only applies with a full THX set-up. I question your integrity. Please provide some more detail to back this up.

[om13934]

THX recomends the crossover at 80hz. for full THX setups (THX certification of dvd player, receiver, interconnects, speaker cable, and speakers) If you don't have a fully THX certified setup, then the 80hz. recomendation doesn't necessarily apply. On a side note, one of my previous posts in the home theater section questioned the pros of THX certification. Apparently THX is no longer owned by george lucas, and no longer makes standards for their certification. Certified products pay a certain amount per sale to receive THX certification, so apparently, "THX Certified" means nothing except that the certified product is paying for that lable (not necessarily performing for it)

[Groovie]

You sort of hit on my point, except you also back what Nicholtl said, and I really wanted to here Nicholtl's perspective. Anyhow the point is that if THX recommends a cross over setting at 80hz, I am saying you are both wrong in saying that it only applies to a full THX set-up. To think that is ludicrous! THX is a certification that a company pays for and so do you when you buy a THX certified equipment. It is a set of rules, origonally developed so that when applied, what you get at home, is what was origonally on the big screen. It is a great standard for the industry. To incorporate any of its guidelines or practices into any setup is a step toward achieving the origonal big screen sound and the essence of THX! You and Nicholtl imply that THX certified equipment is somehow better or different than non certified THX. I am here to tell you that it is only a certification and that there is plenty un-certified equipment on the market capable of achieving and exceeding the benchmarks of THX, so if you have quality equipment from a quality manufacturer, please use the THX guidelines that you can implement with in your control (ie crossover), because that is why THX exists. You will be pleased with the results and that much closer to achieving true home theater!

Please...THX really means that the company you purchased your audio equipment from payed alot of money and jumped through a bunch of hoops to get certification so they can market it to you and charge you through the a--. THX is a great thing for the Home Theater industry, but keep yourself in check with reality!

Compare your hardware with that which is THX certified, if it matches up, where is the need to be concerned with certification? I would however apply all the at home THX guidelines I could.

Again the crossover is your personal preference, your personal THX, so to speak!

[nicholtl]

Easy there Groovie, nobody is attacking you. As a disclaimer, I'm just offering my opinion like anyone else, I'm not claiming to be an expert whatsoever. Hell, at 23, I couldn't be one even if I wished it to be so.

Anyways, yeah you're right, THX certified equipment does in no way, shape, or form instantly suggest it is superior to that which is not. 80hz is what plenty of people set their crossovers to. I was just pointing out that when you said "THX recommends..." it meant that THX usually recommends that when you are using THX speakers, interconnects, placement guidelines etc. But then of course they would, they are a company trying to sell their stuff like any other. But who says you HAVE to have all that stuff before you can set your crossover at 80hz? Not me, and my preamp and both amps are THX Ultra2. Certainly not you either. So no worries there man.

Relax, nobody's picking a fight, and I would offer you a glass of Macallan's 18 on the rocks if you were here. Set your crossover to whatever you like, because like Outback Steakhouse says, "no rules, just right."

PS - hopefully this doesn't open a can of worms regarding companies simply paying for THX to slap their logo on. Some say that, but some argue that it's more than just shoving $$$ down their throats (maybe it's something else too...)

[om13934]

I completely agree with nicholtl. I am not trying to attack your opinion on the crossover setting. I am only saying that THX is no longer owned by the man (George Lucas) who set up the original guidelines. There are still guidelines, but far more products than just the THX certified ones carry those specifications, they just don't pay for the THX logo.(which is why klipsch speakers aren't certified I'm told.) The crossover setting just comes down to how well YOUR setup performs. If all of your surround speakers, (not just your mains) perform well at 80hz, then great, set the crossover to 80, but for me, only the RF15's sound great down to 80hz, the center and surrounds just start to get a little blobby (is that an understandable term?) Although THX recomends 80hz, 100hz crossover gives my system much better performance. So my point is that although it is THX recomended, that doesn't make it universally the best option.

-Jeff

ps.- I got my RW12 today and love it! (time to update the sig. )

[Klipsch Kansan]

First off: Clipping is caused by the amplifier, not the speakers. This is often a misconception. Speakers are usually blown by being underpowered, not overpowered. The "cracking" sounds coming from your speakers is a result of your amp straining too hard to attain the high levels of bass you had them trying to produce. This is why most experts will tell you the more amplifier power you have the safer you are, as the amp is less likely to "clip" if you have that extra "head room."

Second: About the crossover settings and using a sub. I run my rf-15s full range. Their internal crossover will limit power going below their specified range of about 46hz. You shouldn't worry about hurting your speakers running them full range as long as you have good amplification and you don't push them harder than they should be pushed. After all these guys only have 2 5 1/4" woofers per speaker. Cones of this size can only put out so much sound before they start "breaking up" not "clipping."

Third: I use an M&K sub. Pretty pricey, but they are among the best out there. They rate all their subs to go down to 20hz or lower. The more expensive the sub the higher the output at 20hz or lower and so on. M&K pioneered the THX sub and satellite system, if this means anything to you guys. I read a little lower and saw you get into some discussion on THX. I cross my sub over at about 70hz. The rf-15s are specified to go down to 46hz, but I believe their output is -3db at 46hz. The human ear can distinguish differences in volume about every 3db. This means their output at 46hz is noticeably lower in volume than in frequencies above that. I don't have a Sound Pressure Level meter (which you can buy easily from Radio Shack), but my guess is that the speakers start to "roll-off" around 65hz - 70hz. This is why I set my crossover on my sub at about 70hz. This way I'm bridging the gap where the rf-15s output starts to gradually fade to that -3db point. The sub makes up for the difference in volume at 46hz and up to around 70hz.