RBH Sound SX-1212P/R Subwoofer Review

[AcuDefTechGuy]

Not exactly...I get a 6db gain with 2 of my subs 12ft apart and 9db gain total with 3 subs. Double the displacement while maintaining the same voltage swing is a 6db gain. Depending in placement and the room, not all frequencies may see a 6db gain. Some more, some less...but the forum myth that spreading the subs apart only yields a 3db gain is a myth.

Damn myths.

Well...... I guess I learned something new today then.

So what happens when you have FIVE identical subs? Or SEVEN identical subs (in a 7.7 setup)?

 

[Basshead81]

Hey the RBH is by far the new big dog on data-bass.com for commercial offerings. If you can score them at a healthy discount then go for it!!

In regards to your last ADG, after 4 subs it is more diminishing returns then anything. Gains are around 4-5db going from 4 to7 subs, but anything after 4 does nothing to help smooth the response. I personnaly think a 2- 4 sub system is all one needs, but that is just my opinion and that is all it is.

 

[crossedover]

Not exactly...I get a 6db gain with 2 of my subs 12ft apart and 9db gain total with 3 subs. Double the displacement while maintaining the same voltage swing is a 6db gain. Depending in placement and the room, not all frequencies may see a 6db gain. Some more, some less...but the forum myth that spreading the subs apart only yields a 3db gain is a myth.

Only co-locating the subs will give you the 6+ dB increase, and no its not forum myth

 

[Basshead81]

Only co-locating the subs will give you the 6+ dB increase, and no its not forum myth

Yes it is...I have measured and seen the results myself. Also Bill Fitzmaurice who designs speakers and subs states the same. Fwiw there is no such then is co-locating, it's mutually couple but you already knew that.

 

[AcuDefTechGuy]

Yes it is...I have measured and seen the results myself. Also Bill Fitzmaurice who designs speakers and subs states the same. Fwiw there is no such then is co-locating, it's mutually couple but you already knew that.

There is a reason many sources give a range of 3-6dB gain. Perhaps for some rooms and some subs, it is 3dB. But for others, it is 6dB.

 

[Basshead81]

ADG, saying 3db is a blanket statement. Again what we do know is doubling displacement while maintaining the same voltage swing increases 6db and that can not be argued. So somewhere in the room a 6db gain will be present no matter where the subs are placed. At the MLP certain frequencies could see 3db others 6db. So yes I think it is better to say non-mutually coupled is a 3-6db gain depending on placement....mutually coupled within a 1/4 wavelength is a 6db gain.

 

[Steve81]

Some light reading:

Data-Bass

Obviously, you cannot simply assume a static gain of any amount over a substantial frequency range when the system is emitting from multiple points within a room or other confined space. Put simply, gain is not assured at all at any specific frequency. Nor is the maximum gain by doubling the system capped at 6dB at any one frequency due to the complex interaction of all of the forces in play once you confine the system inside an enclosed vessel.

 

[Tom V.]

Only co-locating the subs will give you the 6+ dB increase, and no its not forum myth

Use the 1/4 wave length rule-of-thumb here. That isn't exact because of many variables but it tends to be close IME. Really, it all comes down to phase. If you have two identical sound waves arriving "in phase" you double the amplitude = 6dB.

Tom V.
Power Sound Audiio

 

[AcuDefTechGuy]

Use the 1/4 wave length rule-of-thumb here. That isn't exact because of many variables but it tends to be close IME. Really, it all comes down to phase. If you have two identical sound waves arriving "in phase" you double the amplitude = 6dB.

Tom V.
Power Sound Audiio

Have you measured the effects of 3 - 4 identical subs in the same room?

In this example, if 2 subs = 6dB, then what is the hypothetical potential gain with 3 subs, 4 subs, 5 subs?

 

[Steve81]

In this example, if 2 subs = 6dB, then what is the hypothetical potential gain with 3 subs, 4 subs, 5 subs?

Handy calculator for that:
Pro-Audio and lighting Calculators. Calculator page

Go down to SPL addition, select in phase, and add 3-5 identical numbers together. By that, five identical subs would nominally yield a 14dB increase in output over a single. Four would net a gain of 12dB, and three would yield 9.5dB.

 

[Irvrobinson]

You are perturbed because I would rather put my money on a product that provides the most performance vs price? I would not consider myself a value buyer. I could drop the cash on 4 of those RBH-12's today if I wanted. The issue I have is that I would feel like I was taken to the cleaners. Some people have more money then they know what to do with and choose to buy the most expensive product without performance in mind, others have some money and choose to spend it wisely. Call me the latter...

I would consider the Funk 18.3 on a different level then the RBH. Just the exotic finish alone justifies the cost. Now if the RBH was offered in quilted bubinga or some other exotic finish I could understand the price.

Again the RBH is putting up some impressive numbers!! I just thought it's price is a bit steep. If one could get a healthy discount on a pair then they would have a winner on thier hands . not trying to ruffle any feathers, just offering my opinion in a public forum.

I'm thrilled that you could drop $20K on subs today if you felt like it. The reason posts that follow the "I could get two of x in place of one of y" pattern perturb me, is that if I were a manufacturer reading that stuff constantly on premium product reviews I would be reticent to send my premium products to the sites where the review threads are cluttered up by that thinking, which is virtually every premium product review thread on this site. I sometimes buy premium products and I like to see reviews of them by Audioholics.

 

[Tom V.]

Handy calculator for that:
Pro-Audio and lighting Calculators. Calculator page

Go down to SPL addition, select in phase, and add 3-5 identical numbers together. By that, five identical subs would nominally yield a 14dB increase in output over a single. Four would net a gain of 12dB, and three would yield 9.5dB.

That should be quite close assuming all subs are dialed in and we also consider the 1/4 wave length note. At some point you may see gains slightly higher than the 2=6, 3=9.5, 4=12 (etc) too.

Tom V.
Power Sound Audio

 

[AcuDefTechGuy]

Handy calculator for that:
Pro-Audio and lighting Calculators. Calculator page

Go down to SPL addition, select in phase, and add 3-5 identical numbers together. By that, five identical subs would nominally yield a 14dB increase in output over a single. Four would net a gain of 12dB, and three would yield 9.5dB.

Very cool calculators.

 

[AcuDefTechGuy]

This is purely for fun and hypothetical, but using that cool calculator, assuming all in-phase somewhere in the room:

5 SX1010 + 2 SX1212 ~ 120/124/129/132/133/133/133dB @ 20/25/32/40/50/63/80 Hz.

Now I really want to get dual SX1212 just to see.

 

[AcuDefTechGuy]

I sometimes buy premium products and I like to see reviews of them by Audioholics.

Hells yes!

I love seeing AH reviews of $5K subs, $7K amps and processors, $20K speakers, etc.

 

[gene]

Not exactly...I get a 6db gain with 2 of my subs 12ft apart and 9db gain total with 3 subs. Double the displacement while maintaining the same voltage swing is a 6db gain. Depending in placement and the room, not all frequencies may see a 6db gain. Some more, some less...but the forum myth that spreading the subs apart only yields a 3db gain is a myth.

You should read the Harman papers on this very topic as well as the articles I've written. You don't get the kind of gains you think you do if the subs aren't colocated. The advantage of non-colocated multi-subs is for smoothing bass response not for gaining sheer output. In fact 4 midwall placed subs is about the least efficient placement you could do but it gives you the overall smoothest most consistent results. OF course dealing with predictable room dimensions like a rectangle.

http://www.audioholics.com/subwoofer-setup/multiple-subwoofer-setup-calibration-1

 

[Basshead81]

You should read the Harman papers on this very topic as well as the articles I've written. You don't get the kind of gains you think you do if the subs aren't colocated. The advantage of non-colocated multi-subs is for smoothing bass response not for gaining sheer output. In fact 4 midwall placed subs is about the least efficient placement you could do but it gives you the overall smoothest most consistent results. OF course dealing with predictable room dimensions like a rectangle.

Home Theater Multiple Subwoofer Set-Up & Calibration Guide | Audioholics

I have read them...I have also read the opinions of other respected names in Speaker design. There is not one article that actually states what I said to be wrong. I understand what you are saying, but all 3 of my subs are 9-12ft apart and I get a 9db gain(measured and verified). Not all rooms are alike and some could see less gains. Again saying you only get a 3db gain for subs placed outside of a 1/4 wave length is a blanket statement. I have 3 subs for smoothing purposes, not sheer output, but that still does not mean I am not happy with the gains as well.

 

[gene]

I have read them...I have also read the opinions of other respected names in Speaker design. There is not one article that actually states what I said to be wrong. I understand what you are saying, but all 3 of my subs are 9-12ft apart and I get a 9db gain(measured and verified). Not all rooms are alike and some could see less gains. Again saying you only get a 3db gain for subs placed outside of a 1/4 wave length is a blanket statement. I have 3 subs for smoothing purposes, not sheer output, but that still does not mean I am not happy with the gains as well.

You may have those gains at certain frequencies depending on location measured. You won't get those gains at all frequencies however like you would if all of the subs were in exact same location.

 

[SDFamMan]

Hey guys, just joined the forums and am looking for some advice. I have the T2/R in FL/FR position and a 1212P/R as a separate sub. I am looking for opinions on how to set this up in the best way. I also have 6100c/r for center and 4 661/r for rear and rear surround. Arcam AVR750 decoding surround. Looking forward to the comments. thanks guys!

 

[AcuDefTechGuy]

Hey guys, just joined the forums and am looking for some advice. I have the T2/R in FL/FR position and a 1212P/R as a separate sub. I am looking for opinions on how to set this up in the best way. I also have 6100c/r for center and 4 661/r for rear and rear surround. Arcam AVR750 decoding surround. Looking forward to the comments. thanks guys!

I would set it up as 3 separate subs: 1010 + 1010 + 1212 with the XO @ 80-100Hz.