Why do Pro Subs Suck?

[jaxvon]

It's amazing. In the home audio field, you can find subs that play linearly down to and below 20 Hz at SPLs of 120dB. They're made of tough aluminum or composite cones with thick surrounds. And yet, for some reason, in the pro-audio field, subs peter out in the high 30s, are made with paper cones, and thin surrounds. Why is there such a difference? The goal is the same, to reproduce the music. And yet even given the contraints of durability and ability to play loudly, I think professional designers could do better. Take Mackie for instance. They offer a a 3-way PA speaker that is linear 40Hz to 20kHz. Quite good. But then, their 18 inch subwoofer, only extends down to....45Hz (-3dB). Does someone see a problem here? The PA Speaker only has a 15" woofer! In a smaller cabinet! With less power!

It all makes me feel like live musicians are getting the shaft. Blah.

 

[Az B]

For one thing, music rarely gets lower than 40Hz, so there's not much point.

Secondly, the pro stuff is designed with maximum output and high reliability. 120db at 1 meter is nothing. Some of these babies can output 120db at many meters. And remember, doubling the distance halves the volume.

FWIW, I've had the opportunity to play with some pro subs, and with a little tweaking, they can play pretty low. I know one guy that's got some dual 18" JBL cabs that play down to 15Hz. I've gotten 15" pro cabs to 25Hz without too much strain.

But you don't buy a Ferrari to haul manure, and you don't buy a dump truck to pick up chicks.

 

[jaxvon]

Point taken. I still wonder why they rate some pro subs so high then (response that is). If they can dig down that low, then why do they always go much higher? Hmm, that's probably in the +/-3dB range, but still. Looking at JBL pro subs (single 18" SRX), they still look kinda flimsy.

 

[djoxygen]

Which Mackie sub are you referring to? The HRS-120 doesn't hit -3 until 19 Hz and will do 100 dB @ 1m - more than sufficient for most homes. http://www.mackie.com/products/hrs120/hrs120_specs.html

And the HRS-150 will pump out 122 dB for a few dollars more.

PA subs are a completely different issue. They're built for different purposes, used in different situations, and have different expectations placed on them by their target markets. You should probably not be considering a PA sub for your home theater rig, and likewise, a club would not consider an HT or studio sub for under the stage.

 

[HTnewbie]

I posted on the BagEnd speakers a couple of days ago. I own two of their 18" subs and one 12". You should check them out as they are primarily a pro sound supplier who branched into HT about six or seven years ago. Designed and made in the USA. Very well thought out with none of the apparent snake oil that you all detest. Solid sound no distortion though I have not tested them up at the levels you are discussing.

You can find an independent test/review of the big subs and the monitors I own here:

http://www.bagend.com/bagend/downloads/audiomaginfra&mm8.pdf

 

[BMXTRIX]

Because residential is far superior than 'pro'. Pro actually means 'bargain' while residential usually means 'quality'.

This isn't ALWAYS the case, but about a year ago I switched from home installation to commercial work. The commercial company scoffed at the idea of using consumer grade equipment in a professional installation.

Then I proceded to listed to crappy sound setup after crappy sound setup. They are completely clueless as to what the terms HD and SUBWOOFER mean. They think 70volt speaker systems must be used for anything more than 2 speakers because Crown doesn't make 12 or 16 channel amplifiers... so anyone who does must be crap.

JBL Syntesis equipment is very good - but looks like crap. Most of JBL's commercial lineup looks like crap compared to their home stuff. Why they don't just make a single product that is twice as good makes no sense to me. It never will make sense.

What's even better is companies who have two identical products which get different names depending whether they are for home use, or professional use. They even COST different - but are the identical product out of the box. It's just insane.

 

[Duffinator]

What's even better is companies who have two identical products which get different names depending whether they are for home use, or professional use. They even COST different - but are the identical product out of the box. It's just insane.

Can you give us some examples of this?

 

[Akira]

Pro Subs by a pro

As a pro sound engineer, I can tell you, you have no idea what your talking about. First of all Mackie has never been considered pro by any pro. Even the non educated, should by now realize specs mean absolutely zip...except in pro gear which is never weighted. Why, because professionals have a budget 140 times greater than you and they know what they are buying. Pro speakers use different technology, such as aluminum, nickel colbalt alloys, as opposed to cast iron magnets and are flat wound as opposed to circular. Often they employ double spiders and kevlar cones. You will never find a foam surround (typical of home systems) Why? Because special formulated paper is the most durable substace for that application. This and many more small differences make pro models prohibitively expensive and generally you get a lot less bang for the buck. JBL SRL series are not PRO! They are a cheaper line made for musicians not sound engineers of pro touring companies. Also pro subs almost never fire directly but, rather into each other or through a 'compression slot.' Direct radiating speakers have a deeper response but, then again they don't have to fire 700'. Finally the dimensions of your room, sympathitic to the driver's free air resonance (amplified by the cubic air space of the enclosure) is what decides your low end resonance. Recording studios require a minimum distance of 18' to reproduce 60Hz. So unless you've got a huge room, you will never hear 20Hz, but a harmonic of the fundamental. In large auditoriums the resonant low end fundamental frequency wrecks havoc with open microphones which regenerate into their own source. This, by the way is the definition of feedback, but unless your a pro engineer you would never know that. Akira (Sound Chaser, pro audio)

 

[Transducergeek]

Because residential is far superior than 'pro'. Pro actually means 'bargain' while residential usually means 'quality'.

This isn't ALWAYS the case, but about a year ago I switched from home installation to commercial work. The commercial company scoffed at the idea of using consumer grade equipment in a professional installation.

Then I proceded to listed to crappy sound setup after crappy sound setup. They are completely clueless as to what the terms HD and SUBWOOFER mean. They think 70volt speaker systems must be used for anything more than 2 speakers because Crown doesn't make 12 or 16 channel amplifiers... so anyone who does must be crap.

JBL Syntesis equipment is very good - but looks like crap. Most of JBL's commercial lineup looks like crap compared to their home stuff. Why they don't just make a single product that is twice as good makes no sense to me. It never will make sense.

What's even better is companies who have two identical products which get different names depending whether they are for home use, or professional use. They even COST different - but are the identical product out of the box. It's just insane.

Hello. will you please name the last gear you said is identical pro or home?

 

[BMXTRIX]

Sony's DVD Recorder - I don't know the model number of either, but the day I pulled it out of the box for a commercial job I checked Best Buy the same day and it was the same model. Input for input, output for output - remote control. I checked the model number of each and they were not the same. Weird.

Likewise, if you look at the Marantz PMD-790 or PMD-750 remote controls they are the RC-5200 / 9200 remotes. Marantz also has products it puts into its 'pro' category by taking a product, like a DVD player, and adding rack ears. Suddenly it becomes 'professional'.

The poster above has it right.... but wrong.

Professional DEPENDS on what your definition of professional is. What IS a professional job and product? Is professional a corporate boardroom? Is professional a amphiteater? Is professional a broadcast booth? Is professional a movie theater?

All of those things are professional, and every one needs DIFFERENT products with different sound reproducing capabilities and durabilities. The characteristics of outdoor production work is different than indoor - even if both are 'professional'.

I don't like the term professional at all and don't like the distinction. I do like the idea of being able to use the appropriate product for the job and ignoring the distinctions.

For example: Why is there not ONE DVD recorder on the market with RS-232c control? There are a few DVD players, the only VCR's with it cost over 500 bucks (!!!) and NO DVD recorder has it. Yet, they have plenty of DVD recorders they like to call 'professional'.

Always seems like a joke to me.

I also have to point out that while the professional market will pay more for product, the consumer market buys a TON more product! This means that the professional stuff may actually have a higher charge due to a lack of funds for research and development. You pay more, not for a better product, but for one that isn't produced in the same quantities and one that does not have 1,000,000 other people sharing in the R&D costs. It doesn't necessarily make it a better product because it costs more and is more 'limited' in production. A lot of the larger manufacturers especially, get a lot of cash from consumer marked products to pump into R&D and then built carefully controlled assembly lines that put those products out. Those products are workhorses that last years... Many people here have 'cheap' 10+ year old TV's and VCR's around their home. They were used, are used, and abused daily, but they still work.

The line between consumer and professional is thin at best and in reality, professional does not guarantee any level of quality as one may expect.

 

[cbraver]

EEAAKKKKK!@#$!@#$!$%!#@$%@%@#.

Thank you. The for the amount of home audio knowledge on this forum, this thread is pathetic. Akira, luckly, responded with some of the gripes I was about to bawk (thank you Akira).

In addition....

Pro sound is NOT the same as PA speakers, first off all. No "pro" would use PA equipment without shame. Pro, PA, CLUB, Commercial, Hifi, HT, etc. are all different markets. A night club is not designed the same way as a theater, a home theater product is not designed the same way as a commercial system. The contrast lines are surely being blurred between +4 and -10 gear, but the designs are very different.

It's amazing. In the home audio field, you can find subs that play linearly down to and below 20 Hz at SPLs of 120dB. They're made of tough aluminum or composite cones with thick surrounds. And yet, for some reason, in the pro-audio field, subs peter out in the high 30s, are made with paper cones, and thin surrounds.

Excursion is a durability issue. Professional installations often require the movement of a lot of air not by a smaller number of high excursion drivers but by groups of low excursion drivers moving a lot of air together. But they still use respectable excursion numbers, just not Sunfires. It's just not practicle.

Why is there such a difference? The goal is the same, to reproduce the music.

Yes, it is the same goal to "reproduce music" ... but the installation environment and output requirements are totally different. I'd like to see your home speakers fill up a night club properly, even using large amounts of them.


You talk about frequency response (or the lack of). But think about the requirements of a large venue in terms of output. In terms of the high end (tweeters), home audio loudspeakers are widely available which play above 20,000Hz, but pro audio speakers are often limited to a lower frequency response due to their greater output requirements. Your home speakers can use a small tweeter and maintain low weight and good rigidity which is required to rapidley vibrate and create those high tones. But if pushed, they will blow! As higher output levels are sought for professional applications (in terms of large venue systems like you see to be focusing on the products of) in larger room, the tweeter’s diaphragm will become larger which results in greater weight to maintain rigidity. As the tweeter diaphragm increases in weight it loses the ability to vibrate as rapidly. For the low end, it's the same issue. Excursion is limited for durability and the ability to play at excessively high pressures. Additionally, these subwoofers are meant to be used in groups to reproduce the lower frequencies.

In short, high output sound reinforcement systems require their drivers to operate very natively to their "comfortible" operating range. They can't extend as far as home applications because the stress will simply terror them apart at huge volumes.

You speak of musicians being "short changed" ... but that is hardly the case. A quality venue will sound excellent.

Also excuse my many spelling mistakes and probably lack of support, it's finals week here at Purdue and my brain hurts. Friday evening I'll be able to think again.

-Chad

 

[cbraver]

I should also mention that by using drivers that ARE native to those extremely high frequencies, you can extend that high....there just needs to be a crossover point. Just so that is clear.

For example, BagEnd came up in this discussion, they have a subwoofer called the Bass-assult R that is CROSSED OVER at 50Hz for deep bass extension. Another "subwoofer" would handle the higher deep bass frequencies, then be crossed over to a midbass driver series....then a midrange driver series... etc. etc.

For the high end extension there may be two different tweeters used to extend to that magic 20,000Hz at crazy outputs.


So, I think my last post came off like it can't be done.... well, it can, and it is done all the time... but it's a matter of selecting the right products and installing them correctly.

-Chad

 

[jaxvon]

Finals week here too. In all honesty, I'm just speaking of the PA-ish subs I've used. And even then, I'm speaking mainly of the JBL SR-X line. Their 18" subs (just the singles) seem to roll off pretty quickly. Again, I do understand the purpose, etc. It's just that when I look at them, and hear them, the seem cheap. Obviously the cost is not indicative of that. So, excuse my saying "pro", since that covers so much. I'm talking about PA systems. I already humbled myself to Akira.

Blah. I'm definitely not talking about array subs and pro monitor systems. Anyway, I apologize. It's just that, after using JBL's top of the line PA/Reinforcement system (SR-X), I just felt that the sound was sub-par. Frustration can sometimes make you act before you think.

I must say, that I appreciate people posting and refuting my BS statements. That absolutely reaffirms my faith in this site as well as my own ignorance. I'll just write this off as a "learning experience" and call it a day. Thanks all.

 

[cbraver]

Finals week here too. In all honesty, I'm just speaking of the PA-ish subs I've used. And even then, I'm speaking mainly of the JBL SR-X line. Their 18" subs (just the singles) seem to roll off pretty quickly. Again, I do understand the purpose, etc. It's just that when I look at them, and hear them, the seem cheap. Obviously the cost is not indicative of that. So, excuse my saying "pro", since that covers so much. I'm talking about PA systems. I already humbled myself to Akira.

Can I ask what your doing with a JBL SR-X sub? Was it intended for a party system at school and you wanted big bass so you went with PA stuff? Or were you just looking for a bargain home theater sub?

Blah. I'm definitely not talking about array subs and pro monitor systems.

Haha, I know, but, I get carried away.

Anyway, I apologize.

Bah, don't do that.

It's just that, after using JBL's top of the line PA/Reinforcement system (SR-X), I just felt that the sound was sub-par.

Well, depending on what you own, it just is for your application. If you used it for it's intended application you might like it a bit more... as many DJs that take portable subs to gigs do, for example..

I must say, that I appreciate people posting and refuting my BS statements. That absolutely reaffirms my faith in this site as well as my own ignorance. I'll just write this off as a "learning experience" and call it a day. Thanks all.

haha. We are all ignorant in one way or another. Asking questions is what helps us learn.

You should check out Purdue. It's not too far from you and it has fantastic engineering programs... ME, IE, MET, etc that will teach you all about this stuff, indirectly...or directly if you take the right classes. ...if that's your thing.

Enjoy your learning curve. I'm still on mine!

Oh, and good luck with finals. check your PMs, I sent you something you might enjoy.

-Chad

 

[Akira]

JBL pro?

I should have bought some real estate or stocks instead of the fortune I've spent on James B Lansing. SR-X is JBL's current pro line. (btw, their website jblpro.com is the best equipment manufactuer's site i've ever seen, as in well put together website) In my opinion they are only fair compared to the other high end industry standards. EAW, Turbosound, Meyer, Apogee, & Clair Brothers (Genesis)
JBL never was a builder of P.A. systems. They only make them because they are a speaker manufacturer. I love JBL like many people love Harley, but they do not make a good sound system. They make a GREAT RAW SPEAKER...THE BEST. For this reason the most prestigeous touring companies in the world use their product to design their own systems, as well as theater's and auditoriums, not to mention THX approved movie houses, certified with the Lucus sound Industrial Light and Magic standard. They also make some of the best studio monitors in the world. I have the original Century L100 home version of their most sucessful small studio monitor, model 4310 which was used to master some of the most famous albums ever recorded. They are 32 years old and today, still sound amazing...the 5" midrange has a composite 5 pure element alloy combination and is as large as the ferrite magnet found on a HT sub...that's quality. Their present day consumer line is a cheap imitation made in Taiwan, not California, USA. trying to cash in on the JBL fame. Again, I rate them only fair compared to other consumer products.
p.s. If you want to talk pro, in my opinion the best modern day home and pro studio monitors on the market is Genelec, again a brand you may not know because they are true pro and only distributed by pro audio dealers under the Harmon International line. Akira (Sound Chaser, pro audio)

 

[jaxvon]

Well, actually it's my friend. His Dad has an amateur studio. We've done some shows at the local high school and used the SR-X system he has. We also screw around with the JBL system in the studio, which is a converted garage with sound treatment. Anyway, here's the setup:

Mackie 1640VLZ Pro
QSC PLX3402
Some Signal Processors and Junk
SR4718X Subs
SR4732X Mains

I've never pushed this system near it's limits. I've never had to.

Also, as I PM'd you, I'm in the engineering programs here at U of M, which are also highly rated.