Sam Spoons wrote:Interesting, and like the idea of big voice coils. I'm sure it'll be a great speaker but the specs are no different that the Yamaha DXR15 (700 watts RMS and 133dB, ok it's a bit lighter) and it looks like being around double the price of the DXR's.
When I listened to the Art 722 (at around the same price as the 745) last year I didn't like it as much as the QSC K12, the top end was very nice (with the tweeters 2" voice coil) but I didn't think it sounded better than the K12. Maybe the 745 will be another step up but at a cost.
For me are different in three points:
1) weight DXR15 22.5kg/49.6lbs and ART 745 A 19.6kg/43.2lbs
2) the frequency response graph at RCF is more stabile +/-2db wich is comparable with a studio monitor, DXR is +/-3.5db.
3)for me the ART 745, was built to be used without a subwoofer because the low freq is good enough, the DXR has the settings to be used with a sub but I consider the DXR 10 is a better solution to be used with a sub, anyway DXR 10 has a better sound quality than Dxr 15
the PRX series from JBL are like the low budget speakers, the PRX718XLF has a freq resp from 37Hz - 87 Hz and if u select "hi pass" is applied a 24db filter from 120Hz, what's happening from 87 hz to 120hz ? and the full range has no option to align with a sub like u have on Yamaha DXR series and other speakers
Thanks for your thoughts. I am very keen to hear the RCF 745's as I'm partly tempted to scale my system down a little. Whilst I like having separate tops and subs I'm finding my back is starting to feel it.
"IF" the RCF 745's are a worthwhile step up from the DXR15's (which I still love) in terms of output, clarity and bass response then they may be enough for the large majority of gigs we do!? I have tried the RCF 710's which sounded lovely but I found they had a LOT more hiss than the DXR's. Also, there was noticeable port noise coming from them when playing deeper bass frequencies than with some cheaper Alto speakers I compared them to. This makes me a little hesitant about the 745's as whilst they could potentially put out a lot more bass than the DXR15's will the cabinet handle this well? Also, the 745's are rated at a higher output and I'm concerned as to whether these will have even more hiss than the 710's!?
Really frustrated that I'm unable to hear these locally and will have to travel a long way to be able to do so!
TatarAdrian wrote:the PRX series from JBL are like the low budget speakers, the PRX718XLF has a freq resp from 37Hz - 87 Hz and if u select "hi pass" is applied a 24db filter from 120Hz, what's happening from 87 hz to 120hz ? and the full range has no option to align with a sub like u have on Yamaha DXR series and other speakers
The PRX series speakers are quite nice actually and hardly low budget unless you compare them to something like Meyer. They are by far my favorite speaker in this price range. Nothing on the market that isn't more than 2x the price to implement is really even close.... and even then, only at the penalty of size and weight (the TH118 comes to mind ).
The high pass output of the PRX718XLF internal cross-over is set at 90Hz. Not sure where you got 120Hz from. I am also not sure what you mean by "align with the sub". You run the high pass output of the sub into the tops and run the tops full range. The only signal that will go to the tops will be the >90Hz frequencies.
I'm glad you like the PRX series, but if you read the "PRX700_UserGuide_071813_final_web" on page 14, 18 and 19 you'll see that the sub has a freq response 35Hz - 87Hz at+/-3db, 30Hz - 103Hz at -10db and a internal crossover at 90Hz and 48db. If u don't push the pass thru button the sub will operate from 30Hz - 103Hz at -10db and the full range will operate for eg PRX715 42.9Hz - 19.5kHz at -10db, the result will be to much from 42.9Hz - 103Hz. If u push the pass thru button(it apply a 120hz/ 24db high pass filter) the sub will operate from 30Hz - 103Hz at -10db and the full range will operate for eg PRX715 120Hz - 19.5kHz at -10db.
Please tell me whats happening from 103Hz/-10db to 120Hz/-24db ?
I study this new series from JBL, after he win the NAMM, I saw this problem then. Today I studied again the PRX718XLF, and now is version 5, from the first they changed the DSP frequency from 90 Hz to 100Hz. I put a picture at this link http://ghidboxe.blogspot.ro/2014/10/jbl-prx718xlf.html
(I dont know how to upload a picture from my pc to this forum) with the electronic scheme of the PRX718XLF and I drew with colored lines the route of the signal.
PRX series win the NAMM for technology not for sound.
The info on page 19 contradicts the info on page 14 so one or the other is wrong. Given the other details I'd think page 19 has wrong info on it and the crossover in the PXR subs is 90Hz not 120Hz.
From the first version, which specifications is in manual PRX700_UserGuide_071813_final_web, JBL change the internal DSP frequency cut off, of the subwoofer from 90 Hz at - 48 db filter slope to 100 Hz (the filter slope value is not available) on the latest version from the manual JBL_PRX718XLF_v5 . The high pass filter (wich is for the full range speakers) remain the same, at 120 Hz with a 24 db analog filter slope.
When you don't push the "pass thru button" the signal goes untreated to the output "thru" like blue line and when you push the "pass thru button" the signal pass through the 120Hz "HPF" like red line
That's distinctly odd TA. Crossover frequency is usually stated as the -3dB point for the (linked) LPF and HPF in the crossover. If it wasn't there would be a 3dB hump where the two speakers outputs are summed. When using filters on an input channel it's customary to refer to the frequency where the roll off starts. It could be that JBL are quoting those figures given that the HPF and LPF are separate devices.
Yes, agreed but I'm just guessing why the HPF and LPF roll off frequencies are different. That is the only reason I can think of. The crossover frequency is the point where the HPF and LPF plots cross (usually the -3dB point) the frequency at which the filters start to act will be different to this.
Is another interesting thing on the PRX series, the fan starts when the speaker starts even if the speaker amplifier is cold(doesn't work yet) and has a single speed, the DXR series from Yamaha has 4 speed. When you start a system consists of two full range and two subwoofers, you'll hear the fans.
Yes, (in theory you'd gain about 6dB output and possibly better coverage) and no, (you'd run into potential comb filtering issues which can leaf to weird sounding artefacts as you move around the room). Better to buy speakers that have a higher output and use one per side. In Multiple speaker 'arrays' the individual boxes are designed to be used in combination with others so that the interference effects are minimised/eliminated.
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