ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: [1]   Go Down

Author Topic: JBLSRX828S vs JBLSRX828SP  (Read 365 times)

justinmquinn

  • Newbie
  • *
  • Offline Offline
  • Posts: 2
JBLSRX828S vs JBLSRX828SP
« on: May 26, 2018, 05:50:50 pm »

I posted this over an reddit as well, seeking multiple opinions.  I'm looking into 2 18s for my mobile rig and I've heard good things about the SRX828SP. However it has a "1500 watt RMS / 2000 watt peak class D" amplifier. I looked at the specs and block diagram and it is in fact 750 rms / 1000 peak amp going into a 600 watt RMS driver, that happening at 8ohm of course. Why not a 1200 watt RMS amplifier per driver? That just seems a bit low. I've really had bad experiences with these new lightweight class D and H designs, I just don't think they kick like or are as musical as the old heavy stuff. And this SRX828SP has DSP, I already run a PA2 so that means the signal has to be converted A/D D/A twice. If I get a digital mixer in the future thats 3 times the sound is converted, ouch!

Because of this I'm considering the SRX828S (passive version, which is 1200w RMS, 2400 PROGRAM @ 4OHM) and running it with a bridged RMX4050A. QSC says it can do 4000 at 4ohm bridged at 1kHz, so maybe 3000-3200 at 20-20kHz? That gives a nice amount of headroom over the RMS while also not having to push the amp to the limits at 2 ohms. Im not worried about weight everything has wheels, so factor weight of the 4050 out of the discussion. However the SRX828SP is $2000 and the SRX828S/RMX4050A combo is $3000, so theres that. If I can get a used MA5000i for the price of a new RMX4050A I will do that and do 2 SRX828s a side, consider that option, but I never have access to 20A power so it would have to be on 15A. I'd be willing to use used crown amps if they're under $1,500.

So the bottom line is: underpowered class D amp running at 8 ohms for $2000, or class H amp running conservatively at 2 ohms for $3000 or some other crown amp. I'm just asking for secondary opinions here. I really don't like active speakers, hate them actually. I think the class D amps they put in them can be gutless and shrilly in the top end (of course not a problem in subs tho) and generally sound thinner than my class H passive systems, no to mention having to run XLR AND power to every darn speaker. Much easier to plug the mixer into the rack, rack into power and speakers into rack. I have the E18SW now with an RMX2450 bridged into it at 4 ohms. The KW181 is nice and loud but it sounds thinner in my opinion the old heavy class H amp just sounds thicker. I live considerably far away from retailers so demoing/renting gear isn't always realistically possible for me, so I'm here.

It doesn't have to be SRX828 either, I'd consider other subs in a similar price range.
Logged

Scott Holtzman

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4733
  • Ghost AV - Avon Lake, OH
    • Ghost Audio Visual Systems, LLC
Re: JBLSRX828S vs JBLSRX828SP
« Reply #1 on: May 26, 2018, 06:57:07 pm »

You can't possibly reverse engineer the FIR filters and DSP in the powered speakers.

The 828's are some of the highest output per dollar subs on the market.

You are chasing an inaudible 3db (the difference in power mathematically by your calculations) and that doesn't take into account how poorly amps run with 2 ohm loads.



Sent from my VS995 using Tapatalk

Logged
Scott AKA "Skyking" Holtzman
River Delta Audio is now:

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Luke Geis

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1368
    • Owner of Endever Music Production's
Re: JBLSRX828S vs JBLSRX828SP
« Reply #2 on: May 26, 2018, 07:03:26 pm »

The 828SP is not under powered. The drivers in the passive and powered models are different. Well not different as much as re-applied. The powered model will do what it says. You are thinking like a DJ. WATTS have nothing to do with power and volume. The powered 828SP version will do everything and more than the passive model will do. Why you ask? All the hard stuff is done already in the powered model. All the limiting, eq, protections, crossover settings, everything. It also allows you to edit some of those settings if you wish.

The speakers inside the powered model are slightly different than the passive models. The rating is for each speaker. So that is 750 watts RMS each, ala 1500 watts RMS for the amp itself. The speakers are rated for 600 watts RMS, which is typically 1,200 watts program and 2,400 watts peak. The amp is capable of 2000 watts peak. This means that the amp powers the speakers ideally at right around what would be their program rating. The amplifier has an RMS output of 1,500 watts though, so it will be running at idle while powering each speaker at just above its RMS value. This is perfect. The subs performance specs are real and the amp within it is powering the sub perfectly.

You cannot power a speaker with the peak wattage, if you do, it will very quickly burn up, if not instantly, in very short time. The Program rating is the more ideal wattage to power a speaker to. In this case the program rating of the subs as a whole would be 2,400 watts ( assuming the speakers follow the normal curve ). The amp produces 2,000 watts peak which is only 400 watts shy of the speakers supposed Program rating. That 400 watts is only worth minus 1-1.5db at most ( in other words, it is negligible ) in potential output. The specs suggest an output of 141db!!!! This is no joke. It will get very close to that. I suspect closer to 125db in real world output, but that would still be 5-6db louder than any other sub in this price ranges output.   

Get rid of the PA2. it is not helping you. It would be the weak link if you were to get the powered SRX828SP.
Logged
I don't understand how you can't hear your self

justinmquinn

  • Newbie
  • *
  • Offline Offline
  • Posts: 2
Re: JBLSRX828S vs JBLSRX828SP
« Reply #3 on: May 26, 2018, 07:18:45 pm »

The 828SP is not under powered. The drivers in the passive and powered models are different. Well not different as much as re-applied. The powered model will do what it says. You are thinking like a DJ. WATTS have nothing to do with power and volume. The powered 828SP version will do everything and more than the passive model will do. Why you ask? All the hard stuff is done already in the powered model. All the limiting, eq, protections, crossover settings, everything. It also allows you to edit some of those settings if you wish.

The speakers inside the powered model are slightly different than the passive models. The rating is for each speaker. So that is 750 watts RMS each, ala 1500 watts RMS for the amp itself. The speakers are rated for 600 watts RMS, which is typically 1,200 watts program and 2,400 watts peak. The amp is capable of 2000 watts peak. This means that the amp powers the speakers ideally at right around what would be their program rating. The amplifier has an RMS output of 1,500 watts though, so it will be running at idle while powering each speaker at just above its RMS value. This is perfect. The subs performance specs are real and the amp within it is powering the sub perfectly.

You cannot power a speaker with the peak wattage, if you do, it will very quickly burn up, if not instantly, in very short time. The Program rating is the more ideal wattage to power a speaker to. In this case the program rating of the subs as a whole would be 2,400 watts ( assuming the speakers follow the normal curve ). The amp produces 2,000 watts peak which is only 400 watts shy of the speakers supposed Program rating. That 400 watts is only worth minus 1-1.5db at most ( in other words, it is negligible ) in potential output. The specs suggest an output of 141db!!!! This is no joke. It will get very close to that. I suspect closer to 125db in real world output, but that would still be 5-6db louder than any other sub in this price ranges output.   

Get rid of the PA2. it is not helping you. It would be the weak link if you were to get the powered SRX828SP.

Thank you for your input, I jumped into the spec sheets after posting this and realized the drivers were different, my mistake for making an assumption.  But I suppose I worded my question poorly, as my goal is not an extra 1 or 3 db nor am I trying to run speakers at peak I know to never do that.  Rather what I am trying to get at is- is there any noticable difference in sound quality (maybe "punch" or "thickness") that would be gained using a more traditional class H topology rather than the class D amps.  Thats is all.
Logged

Luke Geis

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1368
    • Owner of Endever Music Production's
Re: JBLSRX828S vs JBLSRX828SP
« Reply #4 on: May 26, 2018, 08:05:15 pm »

In short, no.

Will the passive model sound different than the powered one? Yes, because YOU have to do all the processing for it. The difference in sound will be the difference in the DSP you utilize. DSP which in the powered model already exists. That is to say you can make the powered model sound pretty much however you want it to.

Within the limitation of the speaker, I think the powered model will get you further with less work than any other option currently available at that price point. Punch, thickness, clarity and all the other adjectives to describe a sub is moot. If you have the powered version sitting next to the passive one, the difference in the sound will be because of the difference in processing. Seeing as how sound is subjective, what you perceive as being thick, I might perceive as being muddy, what you perceive as being punchy I might perceive as being woofy. The adjectives that describe what a speaker sounds like is not really of major importance. Really all you need to worry about is does the sub fulfill the need and CAN YOU make it sound as you wish for it too. Since the two models are essentially the same, I would say that the possibilities between them are the same, the difference being how you decide to tune it. You ( which means me and most others out there ) cannot beat the DSP that is in the powered speakers these days. The limiting and protections alone are worth the cost of entry. There is 20 bands of parametric EQ in the powered speaker. That is easily 2x as much eq as any other unit allows. You can adjust the crossover and limiting functions too. The self powered unit will do anything you ask it to within reason, acquiring any of the same potential outcomes as the passive unit.
Logged
I don't understand how you can't hear your self
Pages: [1]   Go Up
 


Page created in 0.067 seconds with 23 queries.