QSC K8 Audition & Some Personal Thoughts
 

Hi Folks,

Today, I finally got to do an audition with a pair of QSC K8 Active speakers at my local Guitar Center--who FINALLY got a pair in for demos. I've been considering getting these or the 10"-woofered QSC K10 speakers as a lightweight alternative to my current Mackie SRM450 classic-model speakers. My first impression of the QSC K8s was underwhelming as the GC Pro Sound manger had the DEEP switches engaged and the units sounded very chesty during my spoken-word audition through an AKG D-5 mic. I had him set everything flat on the speakers and now they sounded better, being crisper and more detailed.

Next, I had him tap into a pair of Mackie SRM450V2 speakers. Immediately, with all EQ set flat, and once again with my spoken-word audition, I thought the Mackies sounded clearer, fuller and more present--even with them sitting on the floor with other speakers on top of them--compared to the QSC K8s that were on speaker stands and at my ear-level. Perhaps, a fairer comparison would have been a pair of QSC K10 or K12 speakers against the Mackie SRM450V2 speakers? All GC had were the one pair of QSC K8 speakers available. Since I already have a pair of like-new Mackie SRM450 classic speakers, I couldn't see buying a pair of the new QSC K Series speakers based on sound or potential volume. The manager said that my three-year old Mackie SRM450 classic speakers are better-sounding, in his opinion, than the newer-design, lighter-weight Class D-amped Mackie SRM450V2 speakers.

Although my audition was a spoken-word audition one, my conclusion is that the new QSC K Series speakers would be an excellent choice as your first-time-buy, high-quality active speakers, or in upgrading from some really cheap speakers OR VERY IMPORTANTLY to save weight over what you may currently own. My Mackie SRM450 classic speakers weigh 51 lbs. per speaker. A new QSC K12 speaker weighs 41 lbs. per speaker, which is the same as a new-design Mackie SRM450V2. I would say that if you already have what you consider a clear, powerful and musical-sounding system, which I consider my Mackies to be, then you may want to wait until your current speakers give out on you before selling them and buying some new QSC K Series speakers. Please be aware that a musical audition using vocals and acoustic guitar may have changed my reported thoughts. I know that my Mackies sound really nice when I'm using them and the QSC products would have to sound significantly better than what I have to cause me to buy them at this time. I could see buying a single QSC K8 or K10, right now, as a small, highly portable single-speaker PA system for vocals/acoustic guitar while still keeping my Mackie speakers. A single QSC K8 or K10 single speaker, with a suitable front-end, per a player's equipment choice, could be a good alternative for someone considering a Fishman Soloamp, a BagAmp, or a Bose L1 Compact as a lightweight, personal PA solution.

Regards,

SpruceTop

Not a very impressive review. And not at all what I have been hearing about the K series on other forums. Guess I have to get out there sometime to hear these for myself. And looking forward to checking out a BagAmp in the near future.

Hi BoB/335,

Again, my audition, being only a bunch of spoken words, in various volumes and frequencies, would have to be considered highly inconclusive and, overall, a flawed comparison as no music was being passed through the speakers at any decent volume level. I have no doubts that the QSC K Series speakers are excellent but they may not blow a person away who already has a quality system. I'd say, for me, it would be kind of silly to throw away my Mackies and buy the QSC speakers. If and when my Mackies blow-up on me, a pair of QSC K Series speakers may be my choice.

Regards,

SpruceTop

It's funny but those Mackie's you have are NOT very highly regarded in the industry by anyone I know. They are boomy and not a clear transparent in the least. Put them up against a K12 and they will be owned. OF course they have more bass then K8s as they should but also they are particularly over bassy so it's no surprise to me. Pumps some music through them and listen to the clarity as compared to the K8s and then K10's and K12's and let us know what ya think.

I am shocked and appalled that you would even consider putting the judgement of your own ears before the Clamor Of Internet Buzz. You have been bad, very bad. ;)

We played a show last year running thru a pro sound guy's Mackies of, I believe, your make, and they sounded stunning, brilliant, killer diller. Granted, he was a very experienced sound dude and we were pumping thru all his gizmos, but still, those are fine speakers.

And I'm generally floored by the quality of the JBL Eons our U's jazz fest uses, so in the end perhaps chasing that final 3% of Holy Grail tone is beyond my ears.

td

Hi Sventvkg,

I was very hesitant to post my spoken-word audition impressions to the board because of the possibilty of pointed responses such as yours, which are justified, no doubt, given my less-than comprehensive auditioning. I'm not sure that your assessment of Mackie SRM450 Active Monitors is correct because hasn't many a solo act and small band relied on these speakers over the last decade or more? To me, they sound crisp and clear, and although they're capable, per specs, of achieving 55 Hz @ -3 dB, and usable to 45 Hz @ -10 dB without any onboard circuitry enhancement, the last thing I would call a Mackie SRM450 is boomy. Please, if anything, call them sterile- or neutral-sounding because of their flat frequency response and I'd know where you're coming from.

My posting wasn't anti-QSC in any way but merely suggested that if a person or band already has a quality small PA system they're happy with at the moment, a QSC K Series speaker just may not be a night-and-day difference for them. Of course, I'd encourage a prospective buyer to audition the new QSC K Series speaker in all manner of ways that may give them a "Eureka" moment and compel them to buy some. For me, given my limited audition, I didn't have that special moment but would definitely consider buying some QSC K Series speakers in the future.

Regards,

SpruceTop

Hi TD,

I think Mackie SRM450 Active Monitor Loudspeakers, because of their widespread usage over the last decade, have become a standard by which to judge portable loudspeakers. With the newer advances in loudspeaker design, including Mackie's own SRM450 update, the SRM450V2, the SRM450 design was, and still is a decent-sounding design. There are new designs, such as the JBL EONS and QSC K Series products that are excellent-sounding and may surpass the sound-quality of Mackie to many ears. I agree with your assessment of "that final 3% of Holy Grail tone is beyond my ears" because given my limited exposure to the QSC K Series tone, I didn't have that allelulia feeling.

I will admit that--excellent tone aside--the prospect of buying a loudspeaker with 1000 watts of power in a 27 lb. to 41 lb. package has got to spin a few heads--mine included. I almost feel I could go to war with a pair of QSC K Series speakers and win any battle I encountered.

Regards,

SpruceTop

Thankfully we still have the BagAmp to consider.

I would challenge anyone to find the actual specs saying "1000w". Not the marketing blurb, but the actual specs.

Bob

The issue, for me, is that the QSC K8 probably does not have an adequate bass response for acoustic guitar and a test using vocals doesn't provide any indication as to how deep the bass response is. Inexplicably, QSC specifications don't provide the industry standard -3 dB frequency response point.

I doubted the claim and called QSC to ask if that was a continuous power rating. They stood by the claim. Neither the specification page of the manual nor the web page define the rating by indicating a distortion level at 1000 watts or a continuous power rating.

http://media.qscaudio.com/pdfs/manua...al_EN_revA.pdf

http://www.qscaudio.com/products/spe...ifications.php

I think it's possible to get a general indication of the K10's loudness with the Max SPL rating. Using those figures, the QSC seems to have an efficiency rating less than the JBL Eon 500 series but with quite a bit more power. Those engineers familar with the actual formula can correct and/or refine the following.

The JBL 510 is rated 220 watts (LF power amp) with a Max SPL of 121 dB. The K10 is rated 500 watts with a Max SPL of 129 dB. Since 10 dB is twice as loud, the K10 is 80% of twice as loud (if you will). Another real world type of approach: Since an increase of 3 dB is noticeable to the human ear, the K10 has almost three additional levels of perceptible loudness.

A comparable 80% increase in the JBL's power would be 396 watts (220 X .8 + 220); therefore, the JBL is definitely a more efficient speaker (i.e., if you put a 500 watt amp in the JBL, theoretically you'd end up with a Max SPL rating closer to 133 dB).

Bottom line: Although not necessarily a better speaker, the QSC is a louder speaker if you require the additional volume for your band and/or venue.

geokie8

Footnote: The K8 is rated 127 dB, and there will obviously be a falloff in the lower frequencies; however, JBL doesn't make an 8" speaker in that series for comparison.

That's something I noticed too. The QSC posted specs are very fuzzy and not complete. At least Mackie and JBL are giving a prospective buyer more complete specs with actual quantifier and limit numbers.

Regards,

SpruceTop

Just thinking out loud a bit about the usefulness of a really loud, ultra-portable/lightweight, small (8-10") cab for acoustic musicians....

When I need to play to a very large crowd (one that would call for lots of volume) I find that someone else provides the PA, and that PA is very large.

When I play an intimate setting requiring high fidelity for a close-listening audience, I find that a very small amount of amplification goes a long ways, and the less the better because, after all, they showed up to listen to *acoustic* music.

When I play a "normal" show the venue is loud because people are having a good time, and although they'll quiet down for half the toons, they're still there to be entertained rather than be awed by high fidelity.

For all of these reasons, I can really see the benefit of a Solo Amp, Bag Amp or Bose system, though the first two make more economical sense to my personal approach to gear and performance...but I can't really see why I'd need to buy a really expensive small/highly portable, 1000 watt powered speaker.

I mean, if it's a big show, take a big speaker, and if it's a big show, certainly portability isn't a concern.

In other words, this debate about this product seems more academic than applicable to the types of music and shows the acoustic musicians I know really tend to play.

Just my thoughts.

td

What he said.

I'm NOT a techie so I probably have NO IDEA what I am talking about.
I don't think you can look at the comparison in that way (by hyperthetically adding 80% increase in power to the formula) I think you have to take it for what ir IS.
Max SPL of 121 dB - Max SPL of 129 dB

Also there is always a falloff in the lower frequencies with every speaker. The K8 claims it goes down to 66Hz at -6dB. Would it not be safe to say that this speaker will cover the low frequencies of an acoustic guitar? (What does the BagAmp claim?)

Those ARE the actual specs. QSC like many companies are using "Class D & E" Digital Switching power amp sections that provide (here to for) unheard of output spec levels.

That said it's VERY difficult to compare output specs and MUCH more importantly compare sonic impact between Digital Class D amps and Analog A or A/B designs.

Comparing specs between two like and similar products, say for instance, a Crest Class A Power Amp and an Ashley Class A Power Amp has some (albeit limited) sonic value.

Comparing the specs of a new design Class D Digital switching Amp to that of Analog Amp is a road to madness. Absolutely sonically meaningless.

Very good points Mr. Hanna. That whole apples and bananas thing.

I've been dabbling in PA for a few years now with a much larger system. Even though I still don't really know what I am doing, I have found that there is a definite correlation between a pleasing sound and power. The more power, the more clean headroom, the less ear fatigue, the more pleasing the sound is. I know that as a fact using JBL MPro415's with what would be called "adequate power" and driving them with Program Rating. The whole tone of the speaker is different with more power.

I am NOT saying that a powered speaker with more power will sound better than a different speaker with less power. There are design and component values in the equation.

The first thing that comes to mind here is I'd hate to be the poor guy standing in front of a two-way 8'' speaker system at 129dB.

I not sure what ANYONE could get out of this spec especially if they're were attempting to apply this to anything that happens in the real world of club playing.

I had a boss once that could scream at me at 129dB. There were NO redeeming sonic benefits from that talent.

Well......yes and no. Again when comparing well designed, like and similar, power amps the equation of more power=more headroom=less distortion holds up fairly well. Although even then it CAN be misleading as some analog amps are MUCH more efficient than others.

Expecting that equation to hold up when comparing (under designed analog) or Digital Power Amps with well built Analog Power Amps is pointless.

I'm willing to put my money in a 300 watt Crest Power Amp any day, all day, endlessly before I'd EVER entertain some of the cheap, light weight 1000 watt Digital Amps.

The 80% figure does come from comparing the Max SPL (i.e., the K10's output is almost twice as loud as the 510 -- but closer to 80%). The rest was theoretical (hence my use of the term "theoretically)."

FWIW, I was only comparing the QSC to the JBL amp -- precisely because they are similar (both class D digital amps, same size, and used for roughly the same purpose).

In addition, Max SPL ratings are taken at 1 meter's distance and there is a volume dropoff depending upon where the speaker is placed (and no, I wouldn't want to be standing 3 feet away from 129 dB -- or 121 for that matter).

geokie8

I've read somewhere that the low E of an acoustic guitar is around 82 Kz.

To my knowledge, there are no specs on the BagAmp; however, representatives have stated that it goes down to 60 Hz (in a personal email to me and posted on AGF elsewhere). Irrespective of the veracity of the statement, I really think the BagAmp's response for an acoustic guitar would be fine -- and buy into the statement that keyboard players and bass players probably need to add the sub.

Hi Joseph,

Which is why, I'd assume, that my three-year old Mackie SRM450 active Monitors, with more conventional but heavier power amps: a Class G, Parametric Servo Feedback for low frequency, and Conventional Class AB for high frequency is probably more reliable under varying operating conditions than the new Class D power-amp-Based Mackie SRM450V2. The older SRM450 is 10 lbs. heavier than the newer SRM450V2. Also, the older SRM450 speakers have a conventional magnet in their low-frequency speaker but the new SRM450V2 low-frequency speakers are neodymium-magnet equipped. Maybe some of that extra weight is worth it for the greater reliability of the SRM450 power amps? What do you think? Thanks.

Regards,

SpruceTop

In audio, particularly live audio, the old adage that "you can't have your cake and eat it to" is a mantra. Light plastic boxes loaded with digital power amps, digital crossovers and neodymium magnet speakers with cheap aluminum frames are unfortunately gonna sound like.......... light plastic boxes loaded with digital power amps, digital crossovers and neodymium magnet speakers with cheap aluminum frames.

I know many who are willing to concede to that because the ability to tote them around with relative ease outweighs the lack of sonic response in their world. I'm good with that as long as we don't start confusing what the specs mean in the real world.

I'm not sure about reliability comparisons. The Digital Amps may well be very reliable. I do know that the market demands the QSC's and The Mackie's and the JBL's be light and powerful. That's what research says you and I want. That said ya just simply can not have light and powerful and concert level cleanliness and tone in one package. Somethings gotta give.

You're NOT gonna see Pink Floyd tour with Digital Power Amps and neodymium loaded turbo packs and for good reason :)

What he said.

geokie8

You will see them with a line array -- but it really shouldn't be compared to a SoloAmp (or BagAmp for that matter).:)

geokie8

Your economical reason is invalid here. A QSC K8 is cheaper than either a Soloamp or Bag Amp. Even throwing in a speaker stand, the K8 is still cheaper than the Bag Amp and several hundreds of dollars cheaper than a Soloamp. Dealers won't discount the Bag Amp either (so they told me) so I can even get a K10 w/speaker stand for less than a Bag Amp.

I still need to compare the K10 to the Bag Amp myself. I compared the BA to the SA and the BA was way better sounding to my ears but I didn't feel it had enough output. If the SQ of the K10 is somewhere in between the SA and BA, I might go for the K10 because of the additional headroom and versatility it will provide me (can use it as a PA, monitor, etc.), plus its not that much heavier than the SA.

GL

The QSC amplifiers are, I think, analog designs. The letter designation in, Class D, does not stand for digital. I'm reasonably certain that the only true digital power amplifier is the MX-D1 made by Yamaha which costs around $5,000. (It delivers 500 watts per/ch with a distortion rating of 0.003% at 1kHz.)

Using the max SPL speaker specifications of the QSC K series and JBL EON to draw inferences is problematic. One would need to know whether limiters are being used and their characteristics and, and of course, how the max SPL is measured, etc. I have the impression that JBL is more conservative with their specifications than QSC.

How are you determining the headroom of the BagAmp and the K10?