Klipsch RF-7, III's question

[pallpoul]

I have the chance to buy a brand new pair , and was wondering if anybody owns or have listened to these speakers can please chime in. I have a pair of Emotiva T-2's, and I do like how they sound, but can't help wondering if the RF-7'III's would be more pleasing, as I Love my heritage series speakers, but due to size/location, in my office location it is a challenge to use them.

 

I will use for 2 channels stereo music only.

 

I have asked this question at another forum, not much info, hope you can stir me in the right direction. 

[YK Thom]

Check out Youthman’s video reviews. If you search the forum you will find them. I would post the link but my IPad isn’t cooperating.

 

[pallpoul]

ty YK Thom

[RLink]

I just purchased a pair of RF 7illls and they sound incredible.  Very crisp sounding and clear.  I also own a pair of Cornwall llls which are equally impressive.  I like them both and would be hard pressed to give a one up on either of them.

 

If space is an issue, then go with the RF 7lll's and as earlier stated, watch the videos by Youthman.

[adam2434]

Got a pair if RF-7 III's late last week.  Currently also own RF-7 II's

 

I'm curious about the III's dual chamber design.

 

Does anyone know if each woofer has its own completely sealed chamber (besides the port of course)?

 

Or, do they share the cabinet volume to some degree?

 

If each woofer has its own enclosure, the volume would be small compared to the volume for the bass drivers in the RF-7 II.  

 

Wouldn't a smaller volume reduce bass output and/or extension vs. the RF-7 II?

 

Don't have a clear understanding of the design and physics of the dual chamber design, so curious...

 

 

[pzannucci]

20 hours ago, adam2434 said:

Got a pair if RF-7 III's late last week.  Currently also own RF-7 II's

 

I'm curious about the III's dual chamber design.

 

Does anyone know if each woofer has its own completely sealed chamber (besides the port of course)?

 

Or, do they share the cabinet volume to some degree?

 

If each woofer has its own enclosure, the volume would be small compared to the volume for the bass drivers in the RF-7 II.  

 

Wouldn't a smaller volume reduce bass output and/or extension vs. the RF-7 II?

 

Don't have a clear understanding of the design and physics of the dual chamber design, so curious...

 

 

Double size for double the woofer. so half the size for the single woofer.  As long as the tuning is appropriate (large enough port for effective output and tuned to the designed roll off) all is fine.

It does sound counter though when thinking of tuning a box, you want the box to have a particular resonant / tuning frequency (possibly ala Helmholtz).  To have appreciable output to match a woofer or multiple woofers, the port / ports area has to be a particular percentage of the woofer / woofers area.  Done properly,  it all comes out in the wash because either the port will need to be larger based on the multiple woofers or the port will need to be smaller, single woofer, smaller box.  Combined together, the port area will be more in line.

Very simplistic view not including air load presented by the rounded / tractrix ports.

[Boilermaker86]

Picture of the RF-7 III on the assembly line....

 

[Paducah Home Theater]

15 hours ago, pzannucci said:

To have appreciable output to match a woofer or multiple woofers, the port / ports area has to be a particular percentage of the woofer / woofers area. 

 

Not really, it's all about air velocity, not solely the size of the woofer.  Whether you have two ports in a large box or one port in a box half that size, the air velocity will be about the same.  It's easy to see if you run it through a calculator:

 

http://www.mobileinformationlabs.com/HowTo-1Woofer-Box-CAL Port lenth 1.htm

 

Type in 4 cubic feet, 2 ports, 3" around, tuned to 35 hz.  You get about 5 1/2".  Now cut it in half and hit calculate.  You get the same thing.  

[Paducah Home Theater]

On 6/2/2018 at 9:59 AM, adam2434 said:

Got a pair if RF-7 III's late last week.  Currently also own RF-7 II's

 

I'm curious about the III's dual chamber design.

 

Does anyone know if each woofer has its own completely sealed chamber (besides the port of course)?

 

Or, do they share the cabinet volume to some degree?

 

If each woofer has its own enclosure, the volume would be small compared to the volume for the bass drivers in the RF-7 II.  

 

Wouldn't a smaller volume reduce bass output and/or extension vs. the RF-7 II?

 

Don't have a clear understanding of the design and physics of the dual chamber design, so curious...

 

 

 

It's completely sealed off and the baffle between them is slanted which reduces standing waves, aka. it cleans up the midrange.  I'm too sleepy to run numbers but otherwise you had standing waves from top to bottom.  I think the bass sounds tighter myself as well but the standing waves is why they did it.  

[Paducah Home Theater]

On 3/25/2018 at 7:29 PM, pallpoul said:

I have the chance to buy a brand new pair , and was wondering if anybody owns or have listened to these speakers can please chime in.

 

 

[pallpoul]

28 minutes ago, MetropolisLakeOutfitters said:

 

 

Ty for pointing to this post. I did buy a pair, and man am I so pleased with them, … From the gorgeous look, to the detailed sound, never fatiguing or harsh .

I have them in my sweet spot for all day listening. I drive them with an NAD M-12 pre amp with an Onkyo M-504, and they sound amazing.

I did try them with an all tube amp n pre amp too,  and they really excel, with base like I have never felt before and musical tone and a sound so rich and smooth yet super clear.

 

I am going to set them up in the next week or two with an all "Cary Audio gear" :Pre amp and DAC and a Tube amplifier amp, the CAD 120Ss MKII,...I can't wait.

I did list my previous, almost brand new still, speakers, the Emotiva T-2's towers, after listening to the RF-7 III's, and never looking back. Yet no body is biting.

  

[pzannucci]

7 hours ago, MetropolisLakeOutfitters said:

 

Not really, it's all about air velocity, not solely the size of the woofer.  Whether you have two ports in a large box or one port in a box half that size, the air velocity will be about the same.  It's easy to see if you run it through a calculator:

 

http://www.mobileinformationlabs.com/HowTo-1Woofer-Box-CAL Port lenth 1.htm

 

Type in 4 cubic feet, 2 ports, 3" around, tuned to 35 hz.  You get about 5 1/2".  Now cut it in half and hit calculate.  You get the same thing.  

Correct, that's why I caveated "very simplistic terms".

 

You are missing the weight of the air in the port, the length of the tube (which makes the weight of the air in the port or spring) and the resistance of the port.  Sure speed has some to do with it but if the port is not appreciably large compared to your woofer cone area, your output from that port will be diminished compared to the woofers.  As the port gets too small, speed is high and you get chuffing or worse noises out of the port.

[adam2434]

Thanks for the posts on the dual chamber cabinet.

 

If I understand correctly, 1 woofer in a 1x volume box does not have to sacrifice extension and output vs. 2 woofers in a 2x volume box.

 

My initial impression of the III's is that the bass is a little leaner than the II's.  Take this with a grain of salt, though.   I did not do back-to-back A/B listening.  I just plopped the III's were the II's were previously.  Perhaps, I was just hearing a bit tighter bass.  I will have to listen more...

 

I am running tone controls flat with the III's.  The II's need a bit a treble reduction in my room/system.  So far, the III's have not produced any of the sharpness that the II's do as the volume is pushed.

 

From the photos above, looks like the cabinet is divided in half by the baffle, and there are windowpane braces at around 1/4 and 3/4 of the cabinet height.  Maybe there is more to the cabinet internals that can't be seen in the photos above.  Seems like the windowpane braces and baffle (also acting as a brace) would make for a super-solid cabinet in terms of resonance.

 

Assuming the RF-7 II also has a couple similar windowpane braces, I wonder how the III gained 10 lbs...interior baffle and bottom plinth adding up to 10 lbs perhaps?

 

 

 

 

 

[Paducah Home Theater]

40 minutes ago, adam2434 said:

Assuming the RF-7 II also has a couple similar windowpane braces, I wonder how the III gained 10 lbs...interior baffle and bottom plinth adding up to 10 lbs perhaps?

 

 

The 7II were a little different, if I remember right there weren't small window pane braces as shown here, it was one big long vertical brace that attached to the sides and was mostly open.  

[Paducah Home Theater]

6 hours ago, pzannucci said:

You are missing the weight of the air in the port, the length of the tube (which makes the weight of the air in the port or spring) and the resistance of the port.  Sure speed has some to do with it but if the port is not appreciably large compared to your woofer cone area, your output from that port will be diminished compared to the woofers.  As the port gets too small, speed is high and you get chuffing or worse noises out of the port.

 

I competed in car audio for many years and have modeled a ton of boxes so here is my potentially misled amateur opinion.  You have to have a proper window of air velocity.  If you make it too small, yeah it chuffs, but,  If you make it too big and there's not enough velocity, it more or less acts like a big hole in the box and the woofers will bottom out because there's no backpressure.  Inside of a ported box the pressures are at least ideally very high because you have this whiplash effect of the in-rushing air, it's enough to keep the cone nearly motionless at the tuning frequency.  If you make the port too big given the situation then it becomes unloaded and the driver will flop like a fish out of water.  Port size to driver size ratio is a byproduct of the other things you need to be looking at which contributes to the velocity such as xMax and tuning frequency but I have never heard of anybody using it as a design consideration from the start.  The closest thing I have ever heard of from people who bypass the proper modeling step is to use a ratio of port size to cubic feet of the box.  This only works most of the time in car audio because tuning is always very similar and everybody seems to use similarly built 15's, otherwise I don't agree with doing that.  

 

[pzannucci]

8 hours ago, MetropolisLakeOutfitters said:

 

  If you make the port too big given the situation then it becomes unloaded and the driver will flop like a fish out of water.  Port size to driver size ratio is a byproduct of the other things you need to be looking at which contributes to the velocity such as xMax and tuning frequency but I have never heard of anybody using it as a design consideration from the start.  The closest thing I have ever heard of from people who bypass the proper modeling step is to use a ratio of port size to cubic feet of the box.  This only works most of the time in car audio because tuning is always very similar and everybody seems to use similarly built 15's, otherwise I don't agree with doing that.  

 

 

I am not saying you are wrong for including velocity but the point is most nothing works correctly at extremes, too small or too large.  Those are the times it does not work but anyone that is trying to design something has a target in mind and should not be trying to overcome physics.  How are you going to move air when the opening is too large?  How are you going to expect good bass output from a port that is too small.  The speed will correlate to the area, volume, and resistance of that port in reference to the box volume and woofer area.  Choose wisely and not on the fringe and you'll likely have a good sounding box.

Also consider delay and transient response, not overall output.  How do you want that box to sound?  Do you want to tune to the woofer's fs or higher or lower, depending on the trade offs you want to build in (it's all a trade off)

[DanSoloRocker]

On 6/3/2018 at 11:25 PM, pallpoul said:

Ty for pointing to this post. I did buy a pair, and man am I so pleased with them, … From the gorgeous look, to the detailed sound, never fatiguing or harsh .

I have them in my sweet spot for all day listening. I drive them with an NAD M-12 pre amp with an Onkyo M-504, and they sound amazing.

I did try them with an all tube amp n pre amp too,  and they really excel, with base like I have never felt before and musical tone and a sound so rich and smooth yet super clear.

 

I am going to set them up in the next week or two with an all "Cary Audio gear" :Pre amp and DAC and a Tube amplifier amp, the CAD 120Ss MKII,...I can't wait.

I did list my previous, almost brand new still, speakers, the Emotiva T-2's towers, after listening to the RF-7 III's, and never looking back. Yet no body is biting.

  

 

Hi, Paul.  How do they compare to the Chorus II's ?  Do you still have those?  I almost bought a pair of RF-7 III's but I may have to wait.