Hey you builders!
Planning to play some music on the streets with some of my pals, i have been looking for a matching portable PA. Now recently people started bringing portable tower PAs (such as the JBL IRX one or the more expensive JBL Eon one mk2) to the gigs in my town. I find these all-in-one solutions really practical, if there were not the "relatively" poor sound (WHERE ARE THE MIDS?), regarding the high price. So i am planning on building a better or at least cheaper one myself. To eliminate the mid gap i thought of building a 3-way-system, where each speaker is in its own enclosure. A fourth enclosure would house the battery, crossover and mixing console. The goal is to be able to assemble them easily at the spot. Having some experience in building speakers, but never even tried a project as complicated, i'd like to post my thoughts and of course building progress here, so you guys can give me your opinions, tipps and tricks. 😉
My Requirements:
What do you think about this idea? I ironically do have a little experience in designing crossovers, but way less in buying speaker drivers. So i am open for alternatives and opinions! Sadly i am, as of right now, unable to find any schematics for a mixing console/power mixer. analogue or digital doesnt matter to me. anyone got a tip? i might as well buy and install a wonky solution like two of these with the input channels altered and put a honey badger amp after them.
Thanks for your opinions and ideas!
TheBigBlubb
Planning to play some music on the streets with some of my pals, i have been looking for a matching portable PA. Now recently people started bringing portable tower PAs (such as the JBL IRX one or the more expensive JBL Eon one mk2) to the gigs in my town. I find these all-in-one solutions really practical, if there were not the "relatively" poor sound (WHERE ARE THE MIDS?), regarding the high price. So i am planning on building a better or at least cheaper one myself. To eliminate the mid gap i thought of building a 3-way-system, where each speaker is in its own enclosure. A fourth enclosure would house the battery, crossover and mixing console. The goal is to be able to assemble them easily at the spot. Having some experience in building speakers, but never even tried a project as complicated, i'd like to post my thoughts and of course building progress here, so you guys can give me your opinions, tipps and tricks. 😉
My Requirements:
- Portable (as in weight, size, etc.)
- Battery powered
- 3 way
- rms between 150 and 600 W (i know its a lot but that leaves me with some room to play with)
- 8 channel mixer (Mono out)
- amp integrated either in the mixer or after the mixer in the same housing
- not exceeding budget of 800CHF (ca. 920 USD)
- 2 x 20000 mah 48V Battery-Pack (probably for either having a backup or in parallel)
- lots of baltic birch 12mm strength (would be cool to achieve a lightweight but sturdy construction)
- A great workshop (suited for wood, metal and esd-sensitive soldering works)
- Lots of in- and output parts for audio connections
- Woofer: B&C 10HPL64 16 Ohm or B&C 12 PE 32 (More better and more Expensive)
- Mid Driver: PD.615C002
- Tweeter: Eminence APT80 V2 (I have another one lying at home, i don't know if its of any use, i'add it here, when i'm at home)
- PCB and remaining parts for the mixing console
- PCB and remaining parts to split power of the batteries to the mixer and amp
- parts for the crossover ( or would something like this work as well?)
What do you think about this idea? I ironically do have a little experience in designing crossovers, but way less in buying speaker drivers. So i am open for alternatives and opinions! Sadly i am, as of right now, unable to find any schematics for a mixing console/power mixer. analogue or digital doesnt matter to me. anyone got a tip? i might as well buy and install a wonky solution like two of these with the input channels altered and put a honey badger amp after them.
Thanks for your opinions and ideas!
TheBigBlubb
JBL IRX One frequency response is given as (±3 dB) 40 - 20,000Hz
For Eon one mk2, its: Frequency Response Hz (±3 dB)45 - 20,000
It could be that the mids are down 6dB, or it could be the mids are perceived as missing due to some other problem. So, first question would be does EQing up the mids, or cutting everything but the mids, give the sound you want? If not, there is probably some non-FR response problem going on. If so, you might want to avoid the same problem with your design.
For Eon one mk2, its: Frequency Response Hz (±3 dB)45 - 20,000
It could be that the mids are down 6dB, or it could be the mids are perceived as missing due to some other problem. So, first question would be does EQing up the mids, or cutting everything but the mids, give the sound you want? If not, there is probably some non-FR response problem going on. If so, you might want to avoid the same problem with your design.
@Markw4 the mids are most of the time just undefined, muddy or (even worse) end up soaking up the adjacent frequencies. this makes having a good mix for anything else than a solo artist nearly impossible, because you normally would give every instrument its own place in the mix.
thanks for pointing this out. i assumed this was because of the missing mid frequency driver, thats why i wanted to put one in the first place 🙂
thanks for pointing this out. i assumed this was because of the missing mid frequency driver, thats why i wanted to put one in the first place 🙂
That can be caused by various problems. Maybe the crossover frequency is there and its causing problems? Maybe there is HD/IMD distortion that is making the midrange muddy? Maybe there is SMPS or Class-D amp, or bad quality dac (if one is used inside) causing some correlated-noise problem affecting the mids? Maybe the whole plastic case is resonating at midrange frequencies?
If you want to troubleshoot, maybe there is a schematic or service manual somewhere? At least it could help to plan out some measurements and or some experiments to help get a better handle on whatever the problem might be. For example, maybe you could try powering the speaker drivers from an external amplifier which you know sounds good? Does that fix it? Or is the mud shown to be mostly coming from the speakers and enclosure design?
If you want to troubleshoot, maybe there is a schematic or service manual somewhere? At least it could help to plan out some measurements and or some experiments to help get a better handle on whatever the problem might be. For example, maybe you could try powering the speaker drivers from an external amplifier which you know sounds good? Does that fix it? Or is the mud shown to be mostly coming from the speakers and enclosure design?
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Cheap 2 way speakers usually run the crossover frequency too high, compared to normal professional guidance. Driven hard, it will have a nasty habit of just falling apart. That’s even not counting the off axis issues which are there all the time.
8 input mono mixer + 150 w rms is a Peavey MMA-8150T. I have scored one of these as low as $75 + freight + tax. It uses +- 42 v rails so two 48 v batteries tied + to - is a natch to replace the AC input and transformer. Unfortunately +-15 comes from its own transformer winding so you will have to fiddle the op amp rails. Vicon makes 48-12 v converters but the 12 v minus is tied to the 48 v minus.
Used MMA-8150t tend to come with one music card, and 1 to 7 telephone cards. The telephone cards are not much use for music. As they are out of production you would have to clone your own music cards. Each music card has two RCA jacks that mix a stereo radio signal down to mono for the warehouse.
A similar product is the Crown MA180.
As for speaker, I found all my 2200 LPs and 200 CDs sounded good on a Peavey SP2-XT or later when that was stolen, Peavey SP2(2004). These are 15" + 1" compression driver on a horn. They sit up 2 m in the air on a speaker stand, and project the highs down 15 degrees to the audience ears. Capable of 500 w AES in the 2004 version. Copying this with drivers other than Peavey 1508KADT and RX22, Should be possible. I am experimenting with Eminence Deltapro-15A woofer and Eminence N314T-8 compression driver 1.4". As the eminence CD is 100 w AES instead of 70 w for the RX22, provides an opportunity to cross the Eminence package lower than 1800 hz of the SP2(2004) and still maintain a 500 w AES rating. Watt limit AES is tested with pink noise at the watt rating for many hours, without damage. The purpose of my eminence clone of the SP2(2004) is to build something ugly without a Peavey rocket logo, that will not be worth $100 cash at any pawnshop or flea market in the country. The Peavey boxes are more rugged and suitable for rough handling by the roadies.
Used MMA-8150t tend to come with one music card, and 1 to 7 telephone cards. The telephone cards are not much use for music. As they are out of production you would have to clone your own music cards. Each music card has two RCA jacks that mix a stereo radio signal down to mono for the warehouse.
A similar product is the Crown MA180.
As for speaker, I found all my 2200 LPs and 200 CDs sounded good on a Peavey SP2-XT or later when that was stolen, Peavey SP2(2004). These are 15" + 1" compression driver on a horn. They sit up 2 m in the air on a speaker stand, and project the highs down 15 degrees to the audience ears. Capable of 500 w AES in the 2004 version. Copying this with drivers other than Peavey 1508KADT and RX22, Should be possible. I am experimenting with Eminence Deltapro-15A woofer and Eminence N314T-8 compression driver 1.4". As the eminence CD is 100 w AES instead of 70 w for the RX22, provides an opportunity to cross the Eminence package lower than 1800 hz of the SP2(2004) and still maintain a 500 w AES rating. Watt limit AES is tested with pink noise at the watt rating for many hours, without damage. The purpose of my eminence clone of the SP2(2004) is to build something ugly without a Peavey rocket logo, that will not be worth $100 cash at any pawnshop or flea market in the country. The Peavey boxes are more rugged and suitable for rough handling by the roadies.
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Separate battery is OK, but multiple enclosures will occupy more space and weigh more than a single cabinet with a mid sub-enclosure, and use more connectors.
If you go with an active three way crossover, three amp channels will also be required.
That said, multi-channel class D amps with digital processing are available cheap, one example:
DC-DC Voltage inverters are also inexpensive, so you are not limited to 48volts as the only operating voltage.
Muddy mids/voca;s is a criticism I often see leveled at these column speaker systems, I think it's a result of comb filtering from a bunch of small drivers all operating in the same bandwidth and possibly the voicing that is baked in.. boom and sizzle sells.
However I'm not sure you will better that result with the drivers you have chosen, the mid in particular appears to be designed for horn loading to a specific waveguide and is likely not suitable as a direct radiator... if that is how you had planned to use it.
A better idea would be a coaxial mid/high combo in it's own box pole mounted over a proper 12" subwoofer. There are quite a few coaxial driver combos out there now starting as small as 4" but I don't see these having enough mid-bass capability to meet a subwoofer. And that is the thing, the mains have to cover everything from 100-120hz up, you can't have an LF driver operating up into the midrange frequencies if you want definition and clarity, so an 8" is probably as small as one should go for a direct radiating design. The coax mid/high combo also creates a true point source for everything it covers which is key for mid/vocal clarity, this or a synergy horn are the 2 best options for achieving this.
However I'm not sure you will better that result with the drivers you have chosen, the mid in particular appears to be designed for horn loading to a specific waveguide and is likely not suitable as a direct radiator... if that is how you had planned to use it.
A better idea would be a coaxial mid/high combo in it's own box pole mounted over a proper 12" subwoofer. There are quite a few coaxial driver combos out there now starting as small as 4" but I don't see these having enough mid-bass capability to meet a subwoofer. And that is the thing, the mains have to cover everything from 100-120hz up, you can't have an LF driver operating up into the midrange frequencies if you want definition and clarity, so an 8" is probably as small as one should go for a direct radiating design. The coax mid/high combo also creates a true point source for everything it covers which is key for mid/vocal clarity, this or a synergy horn are the 2 best options for achieving this.
Yep, running a bunch of small drivers in a wide range does seem to be where these designs fall over.
If I had my time again, I'd go for 4" mid-bass units, and run most of them from 150Hz-800Hz, and a few of them 150Hz-2kHz, crossing to a tweeter.
Run the sub up to 150Hz, and you should be in a reasonably-good place there.
My attempt involved a bunch of 2.5" drivers. Not recommended - the HF balance changed drastically with distance, and that's something I've observed with every column speaker I've listened to, including the Yamaha and EV ones.
Chris
If I had my time again, I'd go for 4" mid-bass units, and run most of them from 150Hz-800Hz, and a few of them 150Hz-2kHz, crossing to a tweeter.
Run the sub up to 150Hz, and you should be in a reasonably-good place there.
My attempt involved a bunch of 2.5" drivers. Not recommended - the HF balance changed drastically with distance, and that's something I've observed with every column speaker I've listened to, including the Yamaha and EV ones.
Chris
hey peeps,
thanks a lot for all the great ideas!
I finally found the time to fiddle around with the ideas and did some scetching:
Looks like i am going to settle with "the classic". This would give me room to have the following drivers:
Sub: B&C 12inch
Mid: Eminence 8inch
Tweeter: Same as above
This would put my total to more or less 300 Bucks for the drivers, which leaves a lot of budget for getting a suiting amplifier and DC-DC converters online.
If i do the crossover by myself, i won't have any power troubles with active crossovers (at least i figure so).
I'mma hop into the designer and will post, before i Build.
Greets
thanks a lot for all the great ideas!
I finally found the time to fiddle around with the ideas and did some scetching:
Looks like i am going to settle with "the classic". This would give me room to have the following drivers:
Sub: B&C 12inch
Mid: Eminence 8inch
Tweeter: Same as above
This would put my total to more or less 300 Bucks for the drivers, which leaves a lot of budget for getting a suiting amplifier and DC-DC converters online.
If i do the crossover by myself, i won't have any power troubles with active crossovers (at least i figure so).
I'mma hop into the designer and will post, before i Build.
Greets
Just a little note that the B&C driver isn't much of a subwoofer. The tiny Xmax will result in distortion as soon as you put any real power in.
I'd recommend playing around in Hornresp or WinISD to figure out what's going to work well.
Chris
I'd recommend playing around in Hornresp or WinISD to figure out what's going to work well.
Chris