I am making a Pro 15 inch 2-way PA monitor with a eminence ASD:1001 compression driver paired with a Dayton Audio H812 1" Exponential Horn and a KAPPA PRO-15A as the woofer. The KAPPA PRO-15A has a Usable Frequency Range of 46 Hz - 4 kHz ,a Resonance(Fs) of 47 Hz and a vas of 5.92 cu.ft. I would like to know what would be the best tuning frequency for the enclosure.The speker will be mostly be used for Hip-Hop,R&B and Dancehall applications
Box Dimensions
H27
W17.5
D18
An angle of 45° at length 8" for a monitor position
An angle of 45° at length of 3" for cosmetic purposes
Woofer link
Speaker Detail | Eminence Speaker
Box Dimensions
H27
W17.5
D18
An angle of 45° at length 8" for a monitor position
An angle of 45° at length of 3" for cosmetic purposes
Woofer link
Speaker Detail | Eminence Speaker
What, exactly, are you trying to achieve?
Here's why most 15" 2-way speakers sound bad, particularly off-axis: they use a small compression driver (and horn) that can't run low enough to meet the 15" cone with a smooth off-axis response.
Most 1" drivers are only happy down to 2kHz or so, and running a 15" cone that high really isn't a good move - they're rough up there, and beamy - the sound in the 1-2kHz region will be coming out like a laserbeam, so only a few people in the audience hear it properly.
If you use a large-format HF driver (and a horn that supports the lower cutoff), you can get the crossover down to the 800Hz range, which is more sensible to meet a 15" midbass.
Even then, though, you aren't going to get loads of bass.
To give you an idea, for a while I ran my PA system with 1x Beyma 15P1200Nd and 1x EV DH1a per side. The EV driver is a good one that allows usefully low crossover points. They Beyma driver is more of a sub driver, but that did mean I was pretty much flat to 45Hz.
However, it was still only a 15" driver on a stand per side.
When you put a speaker up on a stand, you lose about 6dB of bass compared to having it on the floor.
Might not sound like a lot, but 6dB is the same as doubling up on your drivers and amplifiers.
So, 2x 15"s on stands is roughly equal to 1x15" on the floor.
I think you need to set off from the other end of the design process. Figure out which bass notes you want to hit, how loud you want it to be, and go from there.
Chris
Here's why most 15" 2-way speakers sound bad, particularly off-axis: they use a small compression driver (and horn) that can't run low enough to meet the 15" cone with a smooth off-axis response.
Most 1" drivers are only happy down to 2kHz or so, and running a 15" cone that high really isn't a good move - they're rough up there, and beamy - the sound in the 1-2kHz region will be coming out like a laserbeam, so only a few people in the audience hear it properly.
If you use a large-format HF driver (and a horn that supports the lower cutoff), you can get the crossover down to the 800Hz range, which is more sensible to meet a 15" midbass.
Even then, though, you aren't going to get loads of bass.
To give you an idea, for a while I ran my PA system with 1x Beyma 15P1200Nd and 1x EV DH1a per side. The EV driver is a good one that allows usefully low crossover points. They Beyma driver is more of a sub driver, but that did mean I was pretty much flat to 45Hz.
However, it was still only a 15" driver on a stand per side.
When you put a speaker up on a stand, you lose about 6dB of bass compared to having it on the floor.
Might not sound like a lot, but 6dB is the same as doubling up on your drivers and amplifiers.
So, 2x 15"s on stands is roughly equal to 1x15" on the floor.
I think you need to set off from the other end of the design process. Figure out which bass notes you want to hit, how loud you want it to be, and go from there.
Chris
what i am basically trying to achieve is a pa system similar to the EV etx line .im kind of new to this but what i was thinking about was a frequency range of about 40hz - 20Khz
for the tops speaker with a sub woofer with a range of 32hz - 120hz. all paired with a DriveRack PA2. For the tops i would like clarity and a decent mid-bass since the sub will be handling the low notes but if for what ever reason the subs are not present the tops should not sound too flat hence why i am trying to figure out the rite tuning frequency for the 15" 2-way enclosure.As i said i am new to the DIY speaker world so i appreciate every bit of advice i can get
EV ETX line
ETX Portable Powered Loudspeakers by Electro‑Voice
for the tops speaker with a sub woofer with a range of 32hz - 120hz. all paired with a DriveRack PA2. For the tops i would like clarity and a decent mid-bass since the sub will be handling the low notes but if for what ever reason the subs are not present the tops should not sound too flat hence why i am trying to figure out the rite tuning frequency for the 15" 2-way enclosure.As i said i am new to the DIY speaker world so i appreciate every bit of advice i can get
EV ETX line
ETX Portable Powered Loudspeakers by Electro‑Voice
Hmm, old tech 15" mid bass horn driver that would drop into a number of Altec mid bass horns and their clones, so old tech specs a Vas/1.44 cab [ ~116-117 L] tuned to Fs sims a 40 Hz/F10 same as EV, though no way it has the power handling to compete with it.
Old tech 800 Hz/100 deg expo horn mates up to a 15"/100 deg around 1250 Hz enough below its ~1600 Hz XO/80 deg limit, so a little wider than EV's 1500 Hz/90 deg system, so combined with much lower power handling will be limited to smaller rooms/audience density.
All things considered, a good match up and in theory can handle the full 500 W/120 dB/4pi [stand mounted] transients since Xlim is so high the suspension will roll it off several mm before bouncing off the back plate, though of course it would be wise to use a limiter just in case.
GM
Old tech 800 Hz/100 deg expo horn mates up to a 15"/100 deg around 1250 Hz enough below its ~1600 Hz XO/80 deg limit, so a little wider than EV's 1500 Hz/90 deg system, so combined with much lower power handling will be limited to smaller rooms/audience density.
All things considered, a good match up and in theory can handle the full 500 W/120 dB/4pi [stand mounted] transients since Xlim is so high the suspension will roll it off several mm before bouncing off the back plate, though of course it would be wise to use a limiter just in case.
GM
Something to understand here - you're not going to match the performance that EV claims to have. Here's why: Spec Wars: Looking Inside Loudspeaker SPL Specifications - ProSoundWeb
In your position, I'd look for a smaller main speaker, and always take subwoofers. Smaller main speakers means lighter weight and easier to carry (including putting them on stands), and you can use a 1" HF driver which brings costs down.
Something like an Eminence Beta 10CX with an ASD1001 would make a nice compact main speaker. People have already done the crossover work for you, so you'll just need a subwoofer then.
If you absolutely have to stay with a 15" 2-way, you're going to need more money to do it well, or it's just gonna sound like every other cheap 15" 2-way box out there - rough in the midrange, and muddy off-axis.
FWIW, asking 40Hz of your main speakers is a pretty tall order, unless it's for a very small room.
Chris
+1. I think he is trying to build a general purpose PA speaker that could be use as a floor monitor.. which is fine, most of the commercial speakers available these days can do this and the EVs Trev mentioned even have DSP presets for it.
I agree with all the points mentioned so far too, and having owned some of these Kappa Pro 15s for a couple decades and having used them in a few different designs I can second the notion that they don't produce much low bass. In a 5 cu ft box tuned to ~50hz they produce pretty decent "fullrange sound" by '90s music standards which is another way of saying not much bass by todays standards. High passed at 80hz over subs with a 3" CD they make for a potent fat sounding system but this also underlines the near pointlessness of using a 15" for a midbass. For live sound and rock bands in particular this combo is the boss but for any of the popular genres of recorded music you're carrying around a big box for no reason because there just isn't much midbass content, you can do the same job with a 12" or even a 10" midbass. By a mile the speaker combo I most often send out is powered 12+1 tops with 18" subs, this does 99% of all my DJ events. I also own 15" powered PA speakers but only use them when all my 12's are already in use, they can do smaller events without subs but only if the event doesn't need a lot of low bass.. because these boxes don't produce any.
So back to your project. The key to producing clean mids will be the compression driver though so you simply cannot cheap out on it. You should spend at least as much on the CD as you do on the woofer IMO, but I doubt we will convince you to pony up for 2" exit driver so maybe we can talk you into a 1.4" driver like this.. B&C DE610-8 1.4" Titanium Horn Driver 8 Ohm 4-Bolt
Pair that with a 12" woofer like the KappaLite 3012LF and a 1.2khz crossover and you will have something you can be proud of.
thanks for the advise ,i was thinking about a 1.4 CD in the beginning but now am ever more sure about it .but what do you think about the JBL selenium D220 Ti ??
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It's a good 1" CD, I own a couple copies of the older version the D210ti. These are not suitable for crossovers lower than 2khz IMO.
Have al look at off axis response and you will find out that 2 way speakers with a 15" woofer and tweeter, should not be here/made because of it.
They are sold because people want them/put money down for them, based on specs. (10% of the story at most)
I would look for 3 way; separate subwoofers crossed @ 80-125hz and 2 way tops (6-10"woofer(s)) which provide the mids and highs.
They are sold because people want them/put money down for them, based on specs. (10% of the story at most)
I would look for 3 way; separate subwoofers crossed @ 80-125hz and 2 way tops (6-10"woofer(s)) which provide the mids and highs.
You're right, I didn't.
Power compression is long-term thermal build-up and will affect all speakers to some extent. It's dependent on a lot of factors, though, including program material and how each driver deals with getting rid of heat. It's pretty much an article all of it's own, so I avoided it for that one.
Chris
This applies to cheaper models with 1" exit compression drivers. With a 2" exit CD and an 800hz crossover the polar response improves immensely but these drivers are Expen$ive and therefore not found in entry level boxes.
What is your point? All about power compression: Power Handling Vs. Efficiency
"Power compression comes in two distinct forms - thermal (long term) compression, and instantaneous flux modulation compression. Thermal compression upsets the tonal balance of a multi-way system, as the driver with the greatest compression becomes softer with respect to the other drivers in the system. The change in voicecoil impedance with varying temperature will also affect any passive crossover network, with high order networks being the worst affected (they are very critical with respect to load impedance)."
Last part is also a reason why 15"+ tweeter does work better on paper then in real life. Bi amp-ing/ active x-over seems mandatory.
I have not seen/listened to the latest speakers, they might be a bit better.
Can anyone name a 15"+ tweet (or dual 15+tweeter that sounds as good as it's 12"+tweeter little brother or 3 way 15"+6"+tweeter? Thx.
(Drivers don't stop putting out noise a their x-over points)
Any 15" box with a decent compression driver will sound fine, and have more output in the lower midrange than it's 12" equivalent.
3-way systems are a different comparison again.
Chris
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