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Need some general pointers considering Mids/Highs |
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Eagle 
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Joined: 08 February 2025 Status: Offline Points: 10 |
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 Topic: Need some general pointers considering Mids/HighsPosted: 08 February 2025 at 8:26pm |
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Hello all! After lots of lurking on here I've finally decided to make a post, So I have a little humble diy system I like to use for summer house parties in the garden, it consists of 2x 15" Eminence Fane Scoops loaded with some Sovereign Pro 15" LFs... Kicks were some 15inch cheapo active boxes I wired straight into bypassing the (burnt, lol) HFs, I am however currently designing some reflex/sealed boxes for them with a recently aqcuired DATS v3 . Doing this mainly for the learning experience/ upcycling attitude... powered by a Boost PX 1600... outputting about 800w at 4 ohms per channel. I run my two scoops on one channel and my "kicks" on the other channel. Tops are some low level brand active 10 inches and they're ok for the job... So now to the topic at hand, I want to expand my system in the HF and Mids because I deem these very important and I am very lucky and fortunate enough to have been gifted a pair of JBL 2420 compression drivers and 2310 acoustic lens horns. I want my HFs and Mids to be crystal clear, because that always seems to be lackings in all the systems I hear around here. So the plan I have in my head is as follows; 4 Way system; Scoops for sub to about 100hz Sealed/Ported 15" Kicks 100 - 800/900 Hz to meet up with the horns JBL 2420 compression driver w/ 2310 Horns playing from 800 to the highs? No clue what the crossover to the tweeters will be.. Tweeters to take over and get the crisp detail, at which frequency I don't know yet. My questions are as follows, what amps and setup would be ideal for this Mid/HF Section? Is a upper bass 15" reflex/sealed recommended for 100-800hz or will it sound like poo? I was looking at a pair of macrotech 600's to upgrade my amp section but I decided to not go through with it because I realize I don't got a clue on how to safely power low power high impedance compression drivers and I only have a EU wall sockets to run off... Plus the main consensus is that these amps are great for low frequencies but I've read mixed opinions about them and also a cat in the bag situation given the age of these amps now and who might have been inside them... I play a wide range of genres from 90s House, 70s Disco, Soul, 2000s Dubstep, Jazz, Reggae, Dub... I value soundquality over SPL (Or so I think, I will be figuring that out on this journey...) and I'd like to cover about 100-200 people in the future... right now looking at about 50 though hehe... In the future I'll also look into swapping my scoops for 4x BR 18 inch for the bass section for logistics & deep extension reasons... Any pointers and advice is greatly appreciated... |
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fudge22
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Joined: 26 July 2022 Location: UK Status: Offline Points: 263 |
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Posted: 08 February 2025 at 10:36pm |
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I still have some JBL 2420s that I bought back in 1980.
The upper frequency response rolls off above 10KHz and with an 800Hz high-pass cross-over 10W RMS is about their limit, and if you are mainly playing highly compressed music, perhaps even less. Despite their large physical size, they are old and fragile. Having just checked the price on ebay $749 for a pair, I would sell them. For that amount, you could get a pair of modern coax drivers, and would be less likely to blow them up. Either that, or put them on a shelf, admire them, and buy some cheap modern compression drivers. |
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madboffin
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Joined: 03 July 2009 Location: Milton Keynes Status: Offline Points: 1720 |
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Posted: 09 February 2025 at 1:15pm |
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A few questions: I presume your 2310 crinkle-plate lenses include the 2309 horns, to make up a complete 2390 ? They were normally used with 2" drivers such as the 2440. Do you have the 2327 adaptors to fit them to the 1" throat 2420 driver? -- The 2420 was rated at 30W above 800 Hz. They used aluminium diaphragms which are prone to shattering into confetti (as a result of metal fatigue) if driven hard at low and mid frequencies. New diaphragms are expensive. You should check the diaphragms on yours to make sure they are OK, and - but only if you know how to - clean out the gaps. Although some vintage JBL studio monitors used them with passive crossovers, these were not high power systems. I wouldn't want to use one below 1500Hz on a system such as yours, and only then with its own amplifier driven by a 24dB/8ve active crossover and suitable protection - a series capacitor at the very least, and preferably a (Martin style) filter with capacitor, autotransformer, and swamp resistor. They do sound nice, and if you want to add a tweeter you can cross over at 7kHz. The classic JBL systems used either a 2402 ring radiator or a 2405 diffraction slot. As noted by fudge22, if you can't be sure of using them within their limitations, you may be better off selling them. They are highly sought after by hi-fi aficianados, especially in the Far East. I think you would be better off getting some good 2" drivers to fit the lenses, and adding tweeters for 7kHz and above. And build some horn loaded 10" or 12" mids to go between the kicks and 1500 Hz. Edited by madboffin - 09 February 2025 at 1:19pm |
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Eagle
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Posted: 09 February 2025 at 4:34pm |
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Alright, good to know they aren't really suited for PA use... I can't bring it over my heart to sell them, they were given to me by someone I consider a mentor... would be a bit of a middle finger selling them - I think I might keep the 2420 on the shelf for a tube based hifi sometime :)
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Eagle
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Posted: 09 February 2025 at 4:54pm |
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Hey Madboffin, appreciate the input; It is indeed a complete set, so a JBL 2420, 2327 adapter, 2309 horn and finally the 2310 Lens... I have indeed checked the diaphragms and they seem to be fine! Also a sidenote on replacements, originals are indeed expensive but aftermarkets run from 20-40 euros or are these to be avoided at all costs? Thank you very much for a detailed write up on how you would run them! Given their age and expensive it seems a bit of a hassle really for some garden parties 2-3 times a summer... I think I will keep the 2420's for perhaps a bi-amped hifi system with tubes :) I wasn't expecting my system to become a 5 way anytime soon but it seems I don't have much of a choice with a sub & kick section and the 2310 lens' crossover... But my future plans of going BR for subs will allow me to have bass & kicks in one cab (thoughts on this?) so I'd be back to a 4 way then :) What are some good 2" drivers you like and what should I look for?
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Conanski
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Joined: 26 January 2006 Location: Ottawa, Canada Status: Offline Points: 2757 |
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Posted: 09 February 2025 at 5:49pm |
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Edited by Conanski - 10 February 2025 at 6:54pm |
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Line Array
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Joined: 19 March 2022 Location: New Jersey, USA Status: Offline Points: 204 |
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Posted: 26 March 2025 at 4:59am |
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if i was doing a boring but Hi-Fi system i would use a BMS coax above 1.5 khz, a 10" bucket mid from 250 hz to 1.5 khz, 2X15" woofer from 80 hz to 250 hz and two or four 18" or 21" subs.
woofers and subs vented. woofer boxes tuned to 60 hz, sub boxes tuned to 30 hz. no scoops or anything like that. those setups have fallen out of favor with all top manufacturers like JBL etc. so there must be a reason for that. bullet supertweeters also fell out of favor with JBL. QSC Cinema Speaker uses something similar ( BMS Coax with 10" Mid ) crossed at 1,700 hz but they just use four extended low range 15" woofers instead of separate PA style woofers and dedicated subs. but Cinema obviously has different requirements because speakers go behind the screen ... the 10" mid QSC uses is not a bucket but has a custom enclosure but equivalent JBL Cinema Speakers use bucket mids. guess you can go either way. BMS advertises some crazy specs for their coax but i think those are exaggerated. i wouldn't want to take it as low as they say it can go or expect the SPL that they say it can put out, that said i think it is still the best compression driver - even better than ones made out of Beryllium or Textreme Carbon Fiber. for a smaller system like a compact 15" 2-way i would maybe take BMS down to 600 hz or so which is how low RCF takes their 4" drivers to in 15" 2-way systems. for a large system with dedicated 10" midrange i would probably use closer to 1.5 khz crossover like QSC does. the system you were trying to build reminds me a little bit of JBL Marquis Dance Club series that were discontinued. Those had supertweeters and those scoopy looking bass boxes - as i said JBL doesn't use any of that stuff anymore. modern designs i think tend to be simpler / cleaner than the overly-creative ones of the past. the industry is consolidating on the few things that have proven to make the most sense in the widest range of settings - namely bass reflex boxes and compression driver horns. no scoops or supertweeters. JBL also used to sell horn subwoofers - those are gone too. i think we should appreciate the past but let it go.
Edited by Line Array - 26 March 2025 at 5:15am |
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julius111
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Joined: 04 September 2021 Location: cologne Status: Offline Points: 57 |
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Posted: 26 March 2025 at 7:56pm |
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hi,
for the horn and lens, you could make a custom adaptor to use modern drivers. scoops like yours or the jbl 4530, which was paired with your horn back then, can be used 60-1000 hertz, but it depends on the music you want to play if that sounds right. since you have them already… try it! might be better than the cheapos J.  Edited by julius111 - 26 March 2025 at 7:58pm |
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Eagle wrote: