RB-61 vs RB-81 Frequency Response in Terms of Accuracy

[jdgonko]

Hello. Does anyone have an objective (measured) frequency response of the RB-61 and RB-81 speakers? I have asked Klipsch and their sales reps cannot apparently provide me with them. I would also find subjective opinions valuable too.

Enclosure size does not really matter so I'm seeking the model with the flattest (best) frequency response and accuracy. Maximum output level does not matter either (that's what the floorstanders, in a different room, are for) so a 150W RMS of the 81 model versus a 100W RMS of the 61 model isn't an issue. The RB model I end up purchasing will be going into a smaller home office room.

Also, the RB model I choose will likely be augmented by an RW-10d sub to enable the RB's to really shine in their sweet-spot (i.e. keep them from having to actually try and reach their low-end around 45 Hz).

Thank you for any suggestions.

Joe

[wuzzzer]

RB-81 Specifications

frequency response

46Hz-23kHz +/-3dB

RB-61 Specifications

frequency response

43Hz-23kHz +/-3dB

Which is odd since the 61 has a smaller woofer yet it plays deeper? [?]

[jdgonko]

Yes, that is odd but not too unusual. The RB-61's smaller 6.5" woofer driver has close to 1,604 cubic enclosure inches to work with (best case using the enclosure's outer dimensions). The RB-81's 8" woofer driver has close to 2,153 cubic inches to work with but the cone's backside likely subtracts from that more so than the 6.5" cone's does. So, the RB-61, with that extra air to work with and a very compliant surround, its 6.5" woofer could reach that low.

The main question still eludes me though. Which is smoother in frequency response? I would love to see frequency plot graphs for both models!! I'm assuming that the RB-61 would and should be smoother since a great crossover blend for a 6.5" woofer and 1" tweeter should be much easier to achieve than an 8" woofer and 1" tweeter. Plus, the 6.5" cone of the RB-61 should be much more responsive, accurate, and damped.

C'mon Klipsch...show me the real technical measurements! Does that +/-3dB jump all over the place in the critical vocal range? Or, are the RB-61 and RB-81 flat to around +/- 1dB where it counts?

Thanks, Joe

[Raider]

According to the specs above, the speakers are virtually identical, or if anything the less expensive RB61 is superior.  :\ 

Your thread reminds me of this one...

http://forums.klipsch.com/forums/thread/814977.aspx

I don't understand why Klipsch, as a world-class company with world-class product, is reluctant to make comprehensive product data available with which to make more educated choices.

Paul Klipsch sure wasn't shy about it.

[DrWho]

Probably because the mass markets for which they are intended would be misled...raw measurements simply look bad (even on the best of speakers).

I think sound and vision might have done a few measurements on the higher up bookshelves - I that that would be the place I would start looking. Or if anyone is in the Champaign, IL area you can bring some speakers over and we can measure them.

[colterphoto1]

Check the efficiency ratings. Like Doc says, 'it's a compromise' the 81 gives up a tad bit of low end for 2 db efficiency.

[jdgonko]

I appreciate all the comments on this topic. I have decided to go with the RB-61's as the room isn't all that large so I can spare the few extra db's that the RB-81's would offer.

I have even considered using studio monitors, for their extremely flat response, but I think their near-field purposed design would ruin the imaging at a distance outside of 6 to 8 feet...

Thanks again! Joe

[newmm]

Recently, I puchased a pair of M22V2 from Axiom and have been very frustrated. Its db drops sharply from 120Hz(70db) to 80Hz(55db). I think It is due to smaller woofer, about 4 1/4" across, than spec said 5 1/4". Axiom tech said 5 1/4" was measured on the surface. I will return them back.

Then I went to a Klipsch dealer locally to audit RB-61 and RB-81. But Only RB-61 available for listening. I will go back to the store to try RB-81 next week when they receive it.

I have a tech question, RB-81 has 8' woofer + 1"tweeter with crossover @1800Hz. Is it possible to make 8" woofer reproduce upto 1800Hz sound accurately ?

Thanks

[MatrixDweller]

I recently bought some RB-81's and a RC-62 and absolutely love them. I scoured the net looking for SPL graphs of the RB-61 but couldn't find any. I did find one on the RB-81 and RC-62 at Home Theater Mag. I listened to the RB-61's vs the RB-81's at the dealer and the 81's sounded a bit fuller. They are big for a bookshelf speaker. I'm going to get the RF-82's eventually so to match the 8" woofers all around (spare the center...too bad) I think the 81's were the best bet. The power handling will also match all the way around at 150W.

The 81's are considerably more expensive than the 61's however. The list price from my dealer for a pair of 61's was $649 and the 81's were $989 for a pair (I didn't pay list price though). You could always put the money you save into something else like a better DVD player, upgrade your receiver, or whatever. Of course you might always have that burning question in the back of your mind of what if I got the 81's.

Let your own ears be the judge as everyone has different opinions.

[Guest BobG]

MatrixDweller sums it up nicely: "Let your own ears be the judge".

Looking at response curves will not tell you the sonic difference between these two models. I understand that having a concrete test such as a response curve might be very reassuring, but it can actually be quite misleading. Sometimes, small differences in the response plot translate into very large sonic differences and other times what appear to be large visual differences in reponse are not very audible.

People have long sought something other than their own hearing to reassure them of their selection, but there is no single measurement or chart that can adequately describe the performance of a speaker. Would you choose glasses based on a single chart or graph of their optical performance? I don't think so. You have to look through them to judge for yourself.

We don't publish response curves for this reason.

[newmm]

I did listen to both RB61 and RB81, not at the same time though because RB61 were sold before RB81 arrived, in a retailed store with my own musics for half an hour. All the music played were orchistrated from classics to modern soundtracks. Then I purchsed RB81 and have owned RB81 for a month.

RB81 is not drastically superior to RB61. The soundsatge of RB81 sounds wider and I believe why Kilpsch prices them quite different and I will enjoy RB81 over RB61 for long run sonically.

But I must complain that RB81, so is RB61, is too bright(or detail) in high in my taste and therefore causes listenng fatigure in time. It seems designed for a large room with many people talking around while listening. I have other studio monitors which are more balanced between detail and fatigue.