1 JBL MRX sub vs 2 yamaha clubs?

[ckcondon]

I'm currently running 2 Yamaha club IV 18's under my JBL MRX512's. I'd like to replace them with the MRX subs, but don't have the cash for both right now. Would one MRX 18 outperform the 2 Yamaha's with the same power?

I'd consider going with one if I won't lose any of the punch of my current setup.

 

Thanks!

 

Chris

[agedhorse]

I think it would be close, but the MRX would win out. You could sell the existig subs to help your purchase too.

[ckcondon]

Thanks Andy, that's kind of what I figured. I can buy one now and get the second when the Yammies go away.

[Vinny D]

1 to 1 the MRX sub would win out

I would go with the (2) Yamaha subs over the (1) MRX, not saying what would sound better but you have much more air being pushed with the (2) Yamaha subs that they would be noticeably louder.

[agedhorse]

I don't think so Vinny. There are some pretty significant improvements in low frequency efficiency with the MRX cabinets, and this offsets increasing the number/size of the Yamaha cabinets, even with the cabinets receiving more power than the JBL.

 

In my opinion, the benefits of increased efficiency, reduced total size and weight makes the MRX a pretty clear winner, and the cost is about the same (1 MRX vs. 2 Yamaha) so it's a matter of looking at the overall performance and seeing which is the best for the situation.

[witesol]

I don't think 1 MRX single 18 sub will outperform 2 single 18 Yam Club series subs. That's a lot to ask of the MRX. It's not twice the performer of the Yamaha by any means. A bit better, yes. I own both, and 4 of the Yam Club SW15Vs as well.

[ckcondon]

 

I don't think 1 MRX single 18 sub will outperform 2 single 18 Yam Club series subs. That's a lot to ask of the MRX. It's not twice the performer of the Yamaha by any means. A bit better, yes. I own both, and 4 of the Yam Club SW15Vs as well.

 

 

I don't expect one MRX would outperform... just hold it's own for a while until I can buy the second one. I guess my question is more of a "how much different would it sound?" kind of thing.

[witesol]

"outperform" wasn't the right wording, although it's your wording from the original post. i don't think one MRX sub will perform near what 2 yam club subs can do, all things being equal. "Near" is open to debate. Sound quality may be debatable but the amount of low end information just won't be there. 2 18" cones. I prefer to add cabs instead of getting proverbial 'blood out a turnip' approach by adding more power. Whether you can get by, sure.

I don't care what anyone says, it's nice to have the cabs match, carpet doesn't perform as well with sprayed finish. I swear that makes things sound better right off

[agedhorse]

Looking at the specs, the JBL is more believable based on MY EXPERIENCE with the engineering behind these products.

 

JBL: -3dB @45Hz

JBL: -10dB @40Hz

JBL 1/2-space sensitivity: 100dB/1W/1M

 

Yamaha: -3dB not listed

Yamaha -10dB @30Hz (very unlikely, that's a difficult spec to achieve)

Yamaha 1/2-space sensitivity: 96dB/1W/1M (assuming this is accurate)

 

My take (also based on my experience with each sub) is that JBL's specs are pretty darn accurate and that the sensitivity difference between the two is slightly more than doubling up the Yamahas. I also do not see the 30Hz, -10dB point as being realistic with a single cabinet... maybe they test in blocks of 4 and then "normalize" back to 1, which would give approximately this figure.

 

I stand by my opinion.

[witesol]

I'd agree that looks good spec wise if the JBL was actually listed as 100db. My MRX 518 listed at 94. Besides that I've tried them back to back. While I like the sound of the JBLs better, I still doubt the poster will feel the same warmth and bottom end from one cab. I also like the coupling you get from two subs which again, outweighs the specs. If the OP plans on using just a pair, I do like that the MRX are 4 ohm cabs. If you want to expand, then some thought into what power amp you have might be needed.

[agedhorse]

 

I'd agree that looks good spec wise if the JBL was actually listed as 100db. My MRX 518 listed at 94. Besides that I've tried them back to back. While I like the sound of the JBLs better, I still doubt the poster will feel the same warmth and bottom end from one cab. I also like the coupling you get from two subs which again, outweighs the specs. If the OP plans on using just a pair, I do like that the MRX are 4 ohm cabs. If you want to expand, then some thought into what power amp you have might be needed.

 

 

The 94dB spec is a full-space spec and subs generally are not used full-space. Most companies provide only a 1/2-space spec but JBL provides both. The 1/2-space spec is "generally" what you will want to use if comparing numericaly.

[witesol]

I know generally you don't like being wrong, I can appreciate that. I own, and use both Cabs the OP asked about. Frankly I didn't know the exact specs, only my real world test back to back. I won't argue with you since it's counter-productive to answering the question. You used specs to support your opinion. That's cool. I didn't know the numbers exactly but would be fairly sure that the MRX wouldn't do as much as 2 Club SW118. Seems you're reaching a bit now instead of just admitting a simple mistalke and standing by your opinion.

I just happen to have my MRX's manual right here so I looked into a bit, especially after looking at the Mpro subs I found used. Says as plain as day that the 94 sens 1w1m is calculated at a 1/2 space condition. A big footnote right on the book. I bet if you go to www.jblpro.com and download the same book as I have on my desk here, you'd find the same.

 

Is there something I'm missing?

[ckcondon]

The plan is to buy one MRX now and one later so I have a pair. The Yamaha's are OK, but nothing special.

I was just trying to see if there would be a noticeable drop-off in bass by temporarily going with one MRX. Most of the rooms we play are pretty small and the biggest problem I'd face is that I use the subs as pole-mounts for the 12's and I'd need to get at least one speaker stand!

I also realize that the MRX boxes are 4ohm. I'm using a QSC RMX2450 in stereo for the subs.

[witesol]

Good amp. you'll dig the subs. I find the jackplates not as sturdy as I'd like..but they sound good. they're also lighter and smaller, at least in the dimensions that seem to fit my Honda Element..which was a deciding facor for me and a lot of my one-man gigs. two 515s and one or two subs. monitors, amp rack stands, mics. snake, etc all fit. I use one sub frequently so I'm familiar with how it sounds. When I can I center it, or both for that matter.

[agedhorse]

I know generally you don't like being wrong, I can appreciate that. I own, and use both Cabs the OP asked about. Frankly I didn't know the exact specs, only my real world test back to back. I won't argue with you since it's counter-productive to answering the question. You used specs to support your opinion. That's cool. I didn't know the numbers exactly but would be fairly sure that the MRX wouldn't do as much as 2 Club SW118. Seems you're reaching a bit now instead of just admitting a simple mistalke and standing by your opinion. I just happen to have my MRX's manual right here so I looked into a bit, especially after looking at the Mpro subs I found used. Says as plain as day that the 94 sens 1w1m is calculated at a 1/2 space condition. A big footnote right on the book. I bet if you go to www.jblpro.com and download the same book as I have on my desk here, you'd find the same. Is there something I'm missing?

 

 

Yes, you are missing the correct spec.

 

http://jblpro.com/products/portablesound/mrx/MRX518.pdf

 

I'm not sure why you are trying to pick a fight, all I am doing is being accurate and my experience with the cabinets backs up the numbers I see. I am not admitting any mistake, I am not reaching for anything and I stand by my opinion.

[Vinny D]

It's pretty funny that sometimes people say to never trust what the specs say and then the same people turn around and base there decision on what the specs say:poke:

 

 

As I said earlier, the MRX is a better sub..........but one alone will not out perform two Yamaha SW118

 

Thats my decision and I am sticking with it:wave:

[agedhorse]

Vinny, it depends very much on the measurement criteria. Like saying 2 car's top speeds are 120MPH without differentiating that one manufacturer does not account for aerodynamic drag. When tested under identical conditions, the numbers are more revealing. Unfortunately, in this industry, the criteria vary all over the map. Just the difference between 1/2-space and full space testing is absolutely HUGE. There are a lot of very important performance variables hidden between the lines, like how low frequency response can be manipulated with boundery conditions for example.

 

I think that 2 Yamaha subs with the same power as delivered to the JBL will result in similar performance, I think that PROBABLY the JBL will take the edge but when considering the big picture that the OP was considering, the smaller total size, weight and power requirements are substantial decision making factors.

 

Why has this topic raised such a string of challanging comments?

[ckcondon]

Sorry, didn't mean to open a can of worms!

Obviously real world use in a small club is my criteria for evaluation. If I decide to TEMPORARILY use one MRX instead of my 2 Yamaha's, that's what I'm looking at.

I don't think people are going to walk up to me and say "Dude, what did you do? I can't hear any kick or bass!" We don't push a ton of db's and aren't trying to stop people's hearts.

Thanks for all the info and opinions guys... I know I can get away with one sub in most of the rooms we play, and for one or two bigger ones I may use the 2 Yamaha's.

Now play nice!

[witesol]

 

Yes, you are missing the correct spec. http://jblpro.com/products/portablesound/mrx/MRX518.pdf I'm not sure why you are trying to pick a fight, all I am doing is being accurate and my experience with the cabinets backs up the numbers I see. I am not admitting any mistake, I am not reaching for anything and I stand by my opinion.

 

 

My apologies, indeed the footnote says 1/2 space. Sorry for the aggressive nature of my post. I wasn't trying to "pick a fight". I don't generally comment on topics I've no extensive first hand experience with. This particular one I've had plenty.

 

I see no such notation in the Yamaha specs if it is a 1w1m 1/2 space or not? Since most, including LBL list the regular db spec first(only for most) should we simply assume that Yamaha only list a half space figure to make the performance seem better than they are?

 

How much might one see when coupling two speakers together?

 

specs aside, in my experience, literally back to back and plenty of small single sub gigs, the JBL does not perform twice as efficiently as the Yamaha, not even close. I'm not changing my crossover settings at gigs. I have two MRX subs, I also have 4 Yamahas. Any contention that two MRX outperforms 4 Yamahas goes against my experience. That's all.

[aw_dee_o]

Agedhorse:

 

"JBL: -3dB @45Hz

JBL: -10dB @40Hz

JBL 1/2-space sensitivity: 100dB/1W/1M

 

Yamaha: -3dB not listed

Yamaha -10dB @30Hz (very unlikely, that's a difficult spec to achieve)

Yamaha 1/2-space sensitivity: 96dB/1W/1M (assuming this is accurate)

 

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As can be seen, there is a 4 dB difference between the Yamaha and the JBL according to these specific spec's.

 

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Agedhorse said:

 

My take (also based on my experience with each sub) is that JBL's specs are pretty darn accurate and that the sensitivity difference between the two is slightly more than doubling up the Yamahas.

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I would have to assume that Agedhorse is counting on the 3 dB gain when doubling the surface area by using two Yamaha's instead of one. As such, this would take the single 96 dB figure up to 99 dB's. Given that the JBL is supposedly rated at 100 dB's, it is still slightly more efficient according to paper spec. One dB is one dB, if the spec's and testing were done in similar fashion. Having said that, spec's can be derived from several different testing methods. Unless the testing methods are known, any given results are suspect.

 

Here's the problem i have with Agedhorse saying this. If some of you remember, i argued with him and several others here that doubling up on identical drivers ( wired in parallel ) presents a +3 dB gain. Agedhorse and others claimed that this was NOT a valid figure and too high. Yet, in this "debate", it would seem that he's accepting this figure to be relatively true.

 

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Agedhorse said:

I also do not see the 30Hz, -10dB point as being realistic with a single cabinet...

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Due to differences in Thiele-Small parameters of the drivers being used, cabinet dimensions, cabinet tuning, etc... this could very well be a valid figure. To find out why this is happening, you have to look at the Qtc of the system and the impedance curves. It's quite possible to build in a HUGE peak at resonance, which results in a measurably lower F3 and F10. Having said that, the sound quality tends to suffer due to uncontrolled bloat and a lack of amplifier control over the driver.

 

Another factor in the F3 & F10 figures has to do with power input and how the tests were conducted. The tuning frequency, and therefore the F3 or F10, will change as power levels vary. It is normal to achieve a lower F3 and F10 at reduced power levels rather than at higher power levels. As such, if one spec's the system at rated input power vs 1 watt of input, the figures are not really comparable. This is why i said that the specifics of the testing methodology used must be known.

 

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Vinnie D said:

It's pretty funny that sometimes people say to never trust what the specs say and then the same people turn around and base there decision on what the specs say.

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I have to agree with this, as i presented data that wasn't "acceptable" to support a previous premise. The reason for denial? Some of the data was from a manufacturer, and according to the hinvolved parties, the general consensus is "we all know how manufacturers fudge the spec's".

 

Other than that, i think that you'll find there are a lot of double standards that take place not only here with certain individuals, but also with others all around the world.

 

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There are several other factors that i don't see mentioned here that really should be considered. First of all, what frequency range will this "sub" be used in? A true "sub" is used below a woofer, meaning that it is crossed over below 100 Hz. If it is crossed over higher than that, it is being used as a woofer, not a sub.

 

Either way, one needs to look at the frequency response / sensitivity curve for the intended range of use. A published sensitivity spec of 100 dB's / 1w / 1m taken at 400 Hz won't do you ANY good between 40 Hz - 100 Hz of operation. As such, the JBL might be rated higher, but in real world operating conditions within the intended frequency range being quite lower, the single Yamaha might actually be more efficient. Just because a driver / cabinet might show a higher average sensitivity on paper does NOT mean that it will necessarily be more efficient within a narrow band of operation.

 

On top of that, one needs to look at the impedance curves within the intended frequency range of operation. An impedance rating taken at 400 Hz or 1 KHz won't tell you anything about what the driver / cabinet is doing at 40 - 100 Hz. Vague generalizations, which is what most manufacturers provide as spec's, really don't tell the whole tale. You need a BUNCH of spec's of known test parameters in order to really make them usable. Even then, one must know how to properly interpret those spec's, which most people can't. Not even some engineers and a LOT of "industry professionals".

 

Not all apples are Red Delicious. Some are Golden Delicious, some are Fuji's, some are Gala's, etc... They are all apples, but by changing the "formulation" slightly, a LOT of variables change. Same goes for "SUB-woofers", full-range cabinets, amplifiers, etc... Knowing what the variables are and how to properly interpret "real" test results can take you to a higher level of understanding and system building. This is why education is the key to better understanding and system performance. Sean

 

[witesol]

LIke I mentioned I didn't even know the exact specs on the cabs, but I own and use them extensively, like a couple hundred times in the past few years. I have no reason to trust one MFGRs specs and not another. Andy went and found the specs to back up his claim that a single MRX will outperform two Yammie Clubs. I find that not true in my real world scenario. Matter of fact, I tested the cabs back to back and didn't find clear twice the performance of the JBL. So, I go to the specs and look for a reason to suggest why I'm not crazy. I also know that two cabs will always couple and give some level of increase.

 

I see no notation that Yamaha only lists their performance in 1/2 space. And yes, I realize that all kinds of ways of testing can make things look better on paper. I'm not all that interested actually. I mix with my ears. My ears tell me I like the JBL better but it's not simply because it's louder. Anyhow, I'm not as much concerned with the bottom small percentage of the sound as everything else that handles vocals, guitars, keys, cymbals, etc. I didn't make substantial changes in crossover outputs, or EQ setting when switching. Wouldn't it seem that if the JBL was twice as loud as the Yamaha that some manner of adjustment might be needed?

agedhorse, do you own MRX subs and Yamaha subs?

[agedhorse]

 

I see no notation that Yamaha only lists their performance in 1/2 space. And yes, I realize that all kinds of ways of testing can make things look better on paper. I'm not all that interested actually. I mix with my ears. My ears tell me I like the JBL better but it's not simply because it's louder. Anyhow, I'm not as much concerned with the bottom small percentage of the sound as everything else that handles vocals, guitars, keys, cymbals, etc. I didn't make substantial changes in crossover outputs, or EQ setting when switching. Wouldn't it seem that if the JBL was twice as loud as the Yamaha that some manner of adjustment might be needed? agedhorse, do you own MRX subs and Yamaha subs?

 

 

Many (or maybe "most" manufacturers specify their subs as 1/2-space, and that's generally how they are used. JBL happens to give both, and I think based on my experience, that the 1/2-space numbers are what need to be used for comparison. Based on my experience with the Yamaha cabinets, their number is based on 1/2-space measurements.

 

The audible difference is not "double", it's 3dB which requires twice the electrical input power but the ear is a log device and does not detect a doubling of power to be twice as loud. Read up on this topic and I thing you will see why you are confused by what you perceived as a small difference. 3dB is a noticeable difference to most folks but VERY noticeable. A reduction of 3dB of sub crossover output would be all that is required to balance the two cabinets. Think aboout the "small" difference 3dB makes on an eq band as an example of the magnitude we are talking about.

 

I just had a pair of MRX subs in last week for repair, I own a cabinet equiv. to the MP-418, and I have had some of the Yamaha subs in the past but still have customers who bring theirs into the shop on a regular basis for repair. I am quite familiar with all of these cabinets.

 

BTW, for anybody with these cabiners, I still have some recone kits and complete drivers (both standard and upgrade) available for the Yamaha 18" subs, as well as MP-418 parts in stock.

[witesol]

thanks for the information.