Infinity RS152 Review (Surround Speaker)

[abdo123]

with an on-wall mount, considering the depth of the speaker = the distance to the wall. (However, the distance between the center of the woofer and the wall is probably a little bit less than that)

there will be a gigantic further dipping between 200 and 600 Hz.

 

[Vladimir Filevski]

how do you mount it on the wall? you seem to be an expert so what distance does the company recommends?

On the speaker back (where the woofer is), there is a metal mounting plate (with two keyholes), which serves as predetermined exact distance to the wall. Just screw two fasteners in the wall and hang the loudspeaker - it is that simple.
Instruction for mounting, see page 3 from the manual:
https://www.harmanaudio.com/on/dema...66b123/pdfs/Infinity_Reference_152_162_OM.pdf

 

[abdo123]

On the speaker back (where the woofer is), there is a metal mounting plate (with two keyholes), which serves as predetermined exact distance to the wall. Just screw two fasteners in the wall and hang the loudspeaker - it is that simple.
Instruction for mounting, see page 3 from the manual:
https://www.harmanaudio.com/on/dema...66b123/pdfs/Infinity_Reference_152_162_OM.pdf

it doesn't matter, look at the graph above. SBIR will only add further dipping.

 

[Vladimir Filevski]

with an on-wall mount, considering the depth of the speaker = the distance to the wall. (However, the distance between the center of the woofer and the wall is probably a little bit less than that)
there will be a gigantic further dipping between 200 and 600 Hz.

You are confusing combing effect of direct and reflected sound of the woofer - which is not the case here. Here you have, so to speak, only the reflected sound.

 

[abdo123]

You are confusing combing effect of direct and reflected sound of the woofer - which is not the case here. Here you have, so to speak, only the reflected sound.

what would be the case then? if the reflected sound has a dip, and the direct sound has a dip too. then how on earth will that 650Hz dip get boosted?

Please if you're trying to make a point, make sure it's not just 'you're wrong'.

 

[tuga]

A broken panther, well just the panther's legs is enough.

A pink mailman is perhaps a tiny bit misleading...

 

[Francis Vaughan]

The precise shape of the speaker has clearly been designed to work against a wall. Look at the planform. There is intentional diffraction designed for midrange and there is going to be some element of horn loading. Without the rear wall the speaker cannot operate as designed. That is pretty clear.

Think about the wavelengths. This is key. 200Hz is 1.5m. 600Hz is 0.5m The speaker is large wrt these wavelengths, but not huge. 0.5m is going to result is some significant path length differences. Half space radiation versus full space is going to make a big difference too. The woofer is likely significantly loaded when against the wall, so in free space the bass alignment will be well out. At less than about 1kHz (0.3m wavelength) there is going to be no reflected sound from the woofer. It is acting as a horn loaded driver diffracting out past the edges of the cabinet.

Second guessing the exact design reasoning is going to be futile absent a reasonably serious simulation and knowledge of the driver parameters. Given the pedigree of the speaker one might guess that the designers have a bit more of a clue than they are being given credit for here.

I imagine Klippel have a solution to measuring surface mounted speakers, but as usual, I bet it is an optional component that requires one's first born child in payment.

 

[tuga]

Second guessing the exact design reasoning is going to be futile absent a reasonably serious simulation and knowledge of the driver parameters. Given the pedigree of the speaker one might guess that the designers have a bit more of a clue than they are being given credit for here.

As in "this is an effects-speaker, anything goes"?

 

[Francis Vaughan]

As in "this is an effects-speaker, anything goes"?

No.

I really don't get the negative comments here.
It is absolutely clear that measurements in free space are inappropriate with this speaker. It is specifically intended to be wall mounted using the built in mounting points. The huge lumps and bumps are exactly what I would expect, and I would not be surprised to see them totally vanish when properly mounted.
There is good reason there is no panther awarded. There is no useful conclusion that can be drawn from the measurements as they stand. But for some reason there are lots of people here who are demanding a hanging. Maybe they are bored.

 

[tuga]

No.

I really don't get the negative comments here.
It is absolutely clear that measurements in free space are inappropriate with this speaker. It is specifically intended to be wall mounted using the built in mounting points. The huge lumps and bumps are exactly what I would expect, and I would not be surprised to see them totally vanish when properly mounted.
There is good reason there is no panther awarded. There is no useful conclusion that can be drawn from the measurements as they stand. But for some reason there are lots of people here who are demanding a hanging. Maybe they are bored.

You wouldn't expect to see/hear any acoustical interference at the listening spot?

 

[abdo123]

No.

I really don't get the negative comments here.
It is absolutely clear that measurements in free space are inappropriate with this speaker. It is specifically intended to be wall mounted using the built in mounting points. The huge lumps and bumps are exactly what I would expect, and I would not be surprised to see them totally vanish when properly mounted.
There is good reason there is no panther awarded. There is no useful conclusion that can be drawn from the measurements as they stand. But for some reason there are lots of people here who are demanding a hanging. Maybe they are bored.

my SBIR simulations showed that the region below 1KHz will be significantly boosted, So i definitely agree with your assessment.

However, with that being said, the circumstances necessary to get a neutral sound coming out (specially that 600 Hz dip) are so specific that such a design should be purchased with a lot of cautions.

 

[Francis Vaughan]

You wouldn't expect to see/hear any acoustical interference at the listening spot?

From the dual tweeters, probably, but it may not be objectionable. The predicted in-room response is rather well behaved in the high frequencies - until it reaches about 8kHz, where Amir notes Klippel starts to get into trouble, probably because of the choice of computation axis.

 

[Vladimir Filevski]

what would be the case then? if the reflected sound has a dip, and the direct sound has a dip too. then how on earth will that 650Hz dip get boosted?
Please if you're trying to make a point, make sure it's not just 'you're wrong'.

There is no "direct sound" here from the woofer, so to speak. Hence, there is no comb filtering.
If you make anechoic measurements of this loudspeaker from the front side only (where the tweeters are), you will get low-pass-filter-like characteristic (dip at 600 Hz), because all measured woofer "direct" sound actually is coming from diffracted sound wave traveling around the enclosure from the back. If you mount this loudspeaker on the wall (per instructions), there will no low-pass effect (no dip at 600 Hz) because all sound wave will be reflected from the wall and it will be delayed only by one inch (or so) from the "direct" sound wave, so there is no comb filtering effect below 800 Hz and no dip at 600 Hz. That is the point of patented HST technology implemented here.

 

[Francis Vaughan]

However, with that being said, the circumstances necessary to get a neutral sound coming out (specially that 600 Hz dip) are so specific that such a design should be purchased with a lot of cautions.

I think that to understand the 600Kz behaviour one needs to model exactly the shape of the speaker in 3D. The wavelengths involved are of the same order as the speaker size, so one would expect things to be messy to say the least. Wall mounting as provided for with this speaker should provide very highly constrained geometry.

 

[Vladimir Filevski]

If you make anechoic measurement of this loudspeaker with woofer facing the microphone, there will be no dip at 600 Hz (or at least not so pronounced).

 

[JohnBooty]

A weird speaker but I think it also shows your Klippel analysis machine makes certain assumptions about how speakers are used that doesn't apply to every speaker out there. [...] it makes sense that Klippel developed their protocol to measure such speakers, because they are mostly what people buy and use.

@amirm Do you have a support contact (or contract) with Klippel?

This absolutely seems like the kind of thing Klippel should be able to quickly answer... like, is their rig even meant to provide meaningful data for speaker designs such as this?

A quick email/call to Klippel might save a lot of time and head scratching in the future.

 

[MZKM]

The precise shape of the speaker has clearly been designed to work against a wall. Look at the planform. There is intentional diffraction designed for midrange and there is going to be some element of horn loading. Without the rear wall the speaker cannot operate as designed. That is pretty clear.

Think about the wavelengths. This is key. 200Hz is 1.5m. 600Hz is 0.5m The speaker is large wrt these wavelengths, but not huge. 0.5m is going to result is some significant path length differences. Half space radiation versus full space is going to make a big difference too. The woofer is likely significantly loaded when against the wall, so in free space the bass alignment will be well out. At less than about 1kHz (0.3m wavelength) there is going to be no reflected sound from the woofer. It is acting as a horn loaded driver diffracting out past the edges of the cabinet.

Second guessing the exact design reasoning is going to be futile absent a reasonably serious simulation and knowledge of the driver parameters. Given the pedigree of the speaker one might guess that the designers have a bit more of a clue than they are being given credit for here.

I imagine Klippel have a solution to measuring surface mounted speakers, but as usual, I bet it is an optional component that requires one's first born child in payment.

I know Klippel has a baffle for in-wall, don’t think they have one for wall-mount.

 

[beagleman]

Is there a point in reviewing these kind of super low end speakers? People spending so little on audio gear will not read this. The people who do come here on asr never settle for this kind of performance.

I rather see the Genelec 8351b finally being reviewed.

Super low end?

I think many into audio AND home theatre would consider this. After all a big name audio brand.

Super low end to me, means more like Sound design, Lloyds and all in one junk stereos.
This is a very valid lower priced speaker, but no way "Super low end" Yikes!

 

[abdo123]

There is no "direct sound" here from the woofer, so to speak. Hence, there is no comb filtering.

Please explain what you mean with there is no direct sound. there is obviously sound coming out of the drivers.

 

[Gomo]

You will have to build a wall on the back of this then face the opposite direction for listening tests.

I briefly looked a getting bipole speakers for my home theatre setup and quickly discovered that they are not recommended for multichannel music playback because it might sound as though you have installed your B speakers in the bathroom cabinet. They are intended to be mounted on a rear wall to provide surround sound effects without "beaming". Fortunately my seating area is far enough from the surround speakers that I can use monopoles but I can see that these might be useful if I had the couch up against the rear wall.