PC (into) mixer (into) EQ (into) crossover: high pass of crossover (into) JBL's, low pass of crossover (into) subwoofer amplifier (into) drivers.
You would never want to connect an amplifier to your JBL's; the line inputs on the back can't take that much voltage, and besides, they have amplifiers built into the cabinets (that's why you need to plug them into the wall for power). A preamp or anything else that's line level is fine.
Mixing pro and consumer can be a pain, but he appears to have all pro gear already. Personally, I've always had good success with floating pin 3 when mixing the two, but YMMV.
Correct, but for pro line level, 1/4" TRS and XLR are more or less the same thing with a different connector so they can be mixed without issue.
Agreed. A miniDSP can do a whole lot more and is certainly the better way to integrate subwoofer and EQ everything, I just suggested the Behringer because it's simple and should be easy to get working.
The goal = proven + low cost. The D220Ti-OMF($34) crossover on the QSC waveguide($14) is from the Zilch thread. Some constant directivity horn crossovers use a capacitor to boost the treble path, some use more complex circuits to attenuate the lower frequency hi-SPL bumps.
The newer $65 Peerless DFM2544R00 1" compression driver has good measurements and reviews. the 1.75" Ti dome has a plastic coating
Attachments
I assume the PC output is unbalanced.
In my case, it worked fine (no buzzing or mysterious house fires), but intelligibility was lower. The new pro gear was trumped by an old (2nd hand) NAD amp + a simple passive XO.
For my (home) application, the pro gear was literally a waste of space. I sold it at a loss, so that experiment cost me about $800.
The miniDSP is a keeper, and cost much less. Hence I'm mighty biased toward the miniDSP.
That's what I generally assume too, but it sounds like Will is using a digital connection:
Ahh, I misunderstood. Thank you for the clarification.
Here's the thing, the answer to all of those questions is already in this thread or can be found with minimal rescherch. I bring that up because on multiple times in both of your threads you have said:
See, one key to learning is to take the time to digest and understand information that you already have and try to solve new problems with the results of that effort. You have explicitly stated that you want to learn, but if someone else works out each step to your project and what the next step should be, it's no different of a learning experience than building an existing design or a kit.
Here, I'll help you work out the answer to one of the harder questions (which MiniDSP to buy):
In post #8 it's implied that pro sound equipment (like your JBL's and mixer) use a 3-pin balanced connection, and a look at miniDSP's products show that they make product with balanced connections. Furthermore, also in post #8, it's stated that adapters can be used to connect unbalanced and balanced connections (and post #23 brings up that there can at times be undesirable results), therefore you can still use a miniDSP with an unbalanced connection and it's up to you to decide which to go with since they are otherwise identical. Then in posts #11 and #21 there's information to the effect that a miniDSP works as an equalizer and a crossover. Also in #21 it's stated that the source signal needs to eventually be split so that the lower frequencies go to your new subs and the highs to your JBL's, so there's a left and right channel that both need to be split into a high and low feed; so if you go with a miniDSP, you need one that has two inputs and four outputs.
As I have said before, I think this is a project that you can accomplish, but if this is actually going to be a learning experience, you need to take the time to think about and digest the information and references (from your other thread) that you have been given so that this can truly be your project.
Correct. See above.
Either way would actually work, but an answer that fits your needs can be derived from the answer to one of your previous questions:
Unibox is showing you the wattage going into a circuit consisting of those two woofers, not each driver individually. So if we reason on that, it can be concluded that you have two subwoofers that each need their own amplifier.
So when looking for a product to meet that need, it's good to know that something that is called an "amplifier" can have multiple amplifiers in one box. So a stereo amplifier for example actually has two amplifiers in it: one for the right channel and one for the left channel.
I want as little white noise as possible... Would this setup cause it?
PC usb connection to mixer.
Mixer 1/4 connection to Amazon.com: miniDSP 2x4: Musical Instruments
That miniDSP 1/4 connection to JBLs and a 1/4 to rca adapter to Amazon.com: Home Audio Power Amplifier System - 2X120W Mini Dual Channel Mixer Surround Sound Stereo Receiver Box w/ RCA, AUX, Mic Input - For Amplified Speakers, PA, CD Player, Theater - Pyle PTA4: Home Audio & Theater
That amp to each of the subs with the "speaker" output.
(btw I was asking that one question as confirmation and it was cleared up in the next response)
PC usb connection to mixer.
Mixer 1/4 connection to Amazon.com: miniDSP 2x4: Musical Instruments
That miniDSP 1/4 connection to JBLs and a 1/4 to rca adapter to Amazon.com: Home Audio Power Amplifier System - 2X120W Mini Dual Channel Mixer Surround Sound Stereo Receiver Box w/ RCA, AUX, Mic Input - For Amplified Speakers, PA, CD Player, Theater - Pyle PTA4: Home Audio & Theater
That amp to each of the subs with the "speaker" output.
(btw I was asking that one question as confirmation and it was cleared up in the next response)
I have no reason to think there would be an inherent amount of objectionable noise to that equipment chain, but there will also be at least six separate level controls, so you will need to pay attention to gain structure otherwise the system can easily become noisy even if the equipment itself is very quiet.
That is the correct signal flow, but keep in mind that that miniDSP you linked has unbalanced RCA inputs and outputs, so you will need adapters between it and your mixer as well as it and your JBL's. That Pyle amplifier has RCA inputs so you wouldn't need an adapter there.
Also, I would not be surprised if Pyle wasn't being truthful about that units power output. that doesn't necessarily mean it won't have enough power for your needs, just that I doubt that it's actually 120 watts.
Then you're progressing in understanding this, that's excellent. But I apologize for being redundant.
Yeah so I will have 50 - 60 watts headroom for any false advertising...
I can't find any miniDSPs with 1/4 connection, tbh thought those were 1/4 connections but I couldn't find any info saying what connection it really was. I would be fine with the adapters as long as they don't make the quality worse.
MiniDSP doesn't have any models that use a 1/4" connector (as far as I know anyway). This one has balanced connections, it just uses Phoenix connectors rather than TRS or XLR. But as I said earlier, I haven't personally had issues with mixing balanced and unbalanced.
Ok it seems I have all the amps and crossovers understood and picked out. Now back to building the subwoofer.
I posted screenshots of the design and I still should do all the exact calculations (taking away wall volume and bracing volume) to get the right volume for the right port length and diameter. Btw should I take away the volume of the woofers themselves? I don't see their volume in the product details...
I remember people saying to use something like pvc pipe for the ports, how exactly would I get pvc the exact right diameter and length and have 1 flared end?
Also I would like some clearance on what insulation/foam I should buy. Is this simple stuff or should I read about it? Videos were putting foam inside the bracing, I think these were for closed boxes though.
I posted screenshots of the design and I still should do all the exact calculations (taking away wall volume and bracing volume) to get the right volume for the right port length and diameter. Btw should I take away the volume of the woofers themselves? I don't see their volume in the product details...
I remember people saying to use something like pvc pipe for the ports, how exactly would I get pvc the exact right diameter and length and have 1 flared end?
Also I would like some clearance on what insulation/foam I should buy. Is this simple stuff or should I read about it? Videos were putting foam inside the bracing, I think these were for closed boxes though.
Yes. But don't worry about making it 'exact'. If 100 litres is 'perfect', then you add 15 litres to account for bracing & drivers, it won't matter it that's 3 litres more than necessary.
The screenshots look fine, by the way. A very minor (but free) improvement: run the braces slightly to one side, rather than right down the centre of the panels. Asymmetry is good.
Use anything rigid for the ports. Stiff cardboard tubes are fine.
Ports don't have to be cylinders. You can make square ports from scrap MDF.
They don't have to be 'exact'. If the simulator suggests a port of 46.72mm diameter, 50mm diameter is fine. You'd just make the 50mm port slightly longer to keep the same tuning.
If you do 'flanged and flared' ports like in the link, you can do the flaring with almost anything. A file & sandpaper would work. If the point of flaring is to reduce turbulence, then you should flare both ends.
vent tuning
Ported boxes use relatively little stuffing.
Don't buy special acoustic foam. Buy yourself a new pillow, and use the grody old one to stuff your speakers.
If it makes a good difference I will try but I think making the bracing uneven would complicate doing the measurements and cuts by a lot...
Right now I have a Vb of 180 put into the program. I am fine with the Fr anywhere with a Vb of 150 to 180. The thing is that the port length changes up to 10cm longer in that range. With the size of my box, how much should I approx take off the 180 to get a good acurate length?
Btw I'm building a recording booth for some people I'm working with and will be left with 3 extra 12" by 12" acoustic foams. This might not be enough to work with though.
Right now I have a Vb of 180 put into the program. I am fine with the Fr anywhere with a Vb of 150 to 180. The thing is that the port length changes up to 10cm longer in that range. With the size of my box, how much should I approx take off the 180 to get a good acurate length?
Btw I'm building a recording booth for some people I'm working with and will be left with 3 extra 12" by 12" acoustic foams. This might not be enough to work with though.
Bracing: if you can reduce symmetry easily, do it. It is a small benefit that costs nothing ...but not a big deal if you don't wanna bother.
Stuffing: ditto. If you cross to the top box at 200Hz, the stuffing won't do much at all, hence an old pillow will be approximately as (in)effective as anything else.
Some people leave it out entirely, because no stuffing = a slight boost to port output / bass efficiency.
Stuffing: ditto. If you cross to the top box at 200Hz, the stuffing won't do much at all, hence an old pillow will be approximately as (in)effective as anything else.
Some people leave it out entirely, because no stuffing = a slight boost to port output / bass efficiency.
Amazon.com: Precision Port 4 Inch Flared Port Tube Kit: Home Audio & Theater
Something like that seems like a good option, I would just not use the other flared end since I have 1 flared end in UniBox. It would be short by 0.33071 inches in diameter, does that mean I should make the port length longer?
Also is the port length from the start of the flared end to the other end or should I measure from where the tube itself starts?
Something like that seems like a good option, I would just not use the other flared end since I have 1 flared end in UniBox. It would be short by 0.33071 inches in diameter, does that mean I should make the port length longer?
Also is the port length from the start of the flared end to the other end or should I measure from where the tube itself starts?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.