Hi,
I'm learning slowly about how to design and then build passive crossovers and I'm practicing on two drivers I'm interested in potentially building a loud speaker with eventually.
GRS 12PT-8 12" Driver
GRS PT6825-8 8" Planar Mid/Tweeter
I was thinking of using them to build a high sensitivity loud speaker focusing on the 70hz to 20khz range (to then crossover with subs at 80hz or so). I have no modeled the enclosure yet, due to still learning how to even cross these over and as I understand it the enclosure design will be more about the woofer than the tweeter anyways. I'm not sure if I want sealed or ported yet, but I think I may do sealed for this one since I do not need low frequency output below 70hz basically.
I've been learning to use XSim for the crossover circuit and analyzing the graphs. I'm still very new to this. I at least got to the point where I could input the FRD/ZMA data and at least build a simple circuit to show the simulated results in the graph windows. But when it comes to actually producing a nice crossover, I am not there yet.
I'm mostly having trouble with picking a crossover point and then targeting that and then I'm not sure how to target specific places within the graph (such as targeting treble from 8khz to 12khz and dropping only that range a little, etc). I was thinking I wanted to try to crossover somewhere around 1~2khz since this particular planar tweeter has a lot of range and let the woofer pound out the rest down to 70hz. It looks like from the info that maybe 2khz would be ok. But I can't get it to line up for the of life me yet, knowing I know little at the moment.
I'm attaching the FRD/ZMA information on these two drivers to this post if anyone is willing to look at it.
Edit: I attached my XSim project file to simplify things now that I know that can make it easier.
And I'll post my disaster of a design thus far. Again, just trying to understand what I'm doing and what everything does.
I'm trying to just get a fairly flat response from 70hz to 20khz, I'm ok with some things being higher than flat as they can be EQ down with room correction. Any suggestions or help appreciated. I already know that 47uF cap is just pointless, I was just adjusting value to see how the graph would respond. After looking at parts, I realize I do not want to fool with expensive caps.
Thanks!
Very best,
I'm learning slowly about how to design and then build passive crossovers and I'm practicing on two drivers I'm interested in potentially building a loud speaker with eventually.
GRS 12PT-8 12" Driver
GRS PT6825-8 8" Planar Mid/Tweeter
I was thinking of using them to build a high sensitivity loud speaker focusing on the 70hz to 20khz range (to then crossover with subs at 80hz or so). I have no modeled the enclosure yet, due to still learning how to even cross these over and as I understand it the enclosure design will be more about the woofer than the tweeter anyways. I'm not sure if I want sealed or ported yet, but I think I may do sealed for this one since I do not need low frequency output below 70hz basically.
I've been learning to use XSim for the crossover circuit and analyzing the graphs. I'm still very new to this. I at least got to the point where I could input the FRD/ZMA data and at least build a simple circuit to show the simulated results in the graph windows. But when it comes to actually producing a nice crossover, I am not there yet.
I'm mostly having trouble with picking a crossover point and then targeting that and then I'm not sure how to target specific places within the graph (such as targeting treble from 8khz to 12khz and dropping only that range a little, etc). I was thinking I wanted to try to crossover somewhere around 1~2khz since this particular planar tweeter has a lot of range and let the woofer pound out the rest down to 70hz. It looks like from the info that maybe 2khz would be ok. But I can't get it to line up for the of life me yet, knowing I know little at the moment.
I'm attaching the FRD/ZMA information on these two drivers to this post if anyone is willing to look at it.
Edit: I attached my XSim project file to simplify things now that I know that can make it easier.
And I'll post my disaster of a design thus far. Again, just trying to understand what I'm doing and what everything does.
I'm trying to just get a fairly flat response from 70hz to 20khz, I'm ok with some things being higher than flat as they can be EQ down with room correction. Any suggestions or help appreciated. I already know that 47uF cap is just pointless, I was just adjusting value to see how the graph would respond. After looking at parts, I realize I do not want to fool with expensive caps.
Thanks!
Very best,
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Thanks, that's more helpful to know! I will do that.
Edit: Added to my original post. Thanks!
Very best,
Ok, re-did some things to try and do better. I kind of like this better, more like a house curve.
Can't seem to get rid of that 800hz dip though.
Edit: Bleh, just realized I didn't slop off the tweeter and it's trying to output down to 300hz. Back to the drawing board.
Ok, I re-uploaded with the tweeter highpass in place. I'm happier (meh) with this at the moment other than the dip around the crossover. Any ideas?
XSim project attached.
Very best,
Can't seem to get rid of that 800hz dip though.
Ok, I re-uploaded with the tweeter highpass in place. I'm happier (meh) with this at the moment other than the dip around the crossover. Any ideas?
XSim project attached.
Very best,
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What are your thoughts on having chosen a dipole mid/tweeter to cross monopole at around 1k?
These are probably going to need a complex crossover, we can explore that if you don't have any reservations.
These are probably going to need a complex crossover, we can explore that if you don't have any reservations.
Honestly just was looking at those two drivers because they were sensitive and cheap enough to tinker with, so maybe could make something sensitive to get loud on low power (AVR). Would like to have decent quality, but for a first build I'm not expecting the best.
I'm open to nearly anything. I'm totally a novice at this. I'm just exploring what it would take to build a high sensitivity loudspeaker for home theater. I know what I would buy commercially, but it would be more fun to just learn to make them. I'd love to find a good way to build something like the DIYSG HT12's or PSA M110's. I'd love to find a way to build something around ~96db sensitivity with a 70hz~20khz range. I don't care if it's a 2 way, or something else. Trying to work out something with good horizontal dispersion to work well as a center channel and maybe duplicate it for the front mains. I'm ok with big boxes.
If there are better, easier drivers to work with for the crossover that are high sensitivity, I'm happy for suggestions. I found these just browsing on P.E.
Very best,
Thanks, I didn't read enough on that tweeter I suppose. I was clicking through finding high sensitivity tweeters with FRD/ZMA files available (on P.E.) so I could model things and skipped any that didn't have that info since I couldn't measure myself or model it without that info that I know of.
I'm not married to either driver. They are just what I started with due to sensitivity and their respective ranges. I could swap to a different tweeter or woofer no problem. Any suggestions?
Very best,
Many like to start with a dome tweeter because they are easier to set up. A dome tweeter usually works with a mid no larger than around 6". If you want larger you can go to a 3-way.
Or you could look at compression tweeters and horns. These are very sensitive, and larger. They will give high output and can be crossed directly to larger woofers like a 12".
Or you could look at compression tweeters and horns. These are very sensitive, and larger. They will give high output and can be crossed directly to larger woofers like a 12".
Thanks; I wanted to use a compression driver horn, but I couldn't find its FRD/ZMA data so figured I couldn't model it. So then moved on to other tweeters with the data to try to learn to model this stuff to build crossovers.
I was looking these: Celestion CDX1-1445, PRV D280Ti-S
But didn't see the info to model them.
Very best,
You wouldn't. They change when you put them on a horn. The horn you choose is important for how they perform.
If you aren't prepared to measure you could use standard procedures and base your crossover choices on listening.
If you aren't prepared to measure you could use standard procedures and base your crossover choices on listening.
Ok thanks, dang, I like modeling to be able to get an idea of it before committing to cutting the enclosure and/or buying something.
I have no problem measuring stuff, I like doing that. Just didn't realize I had to build the box, buy a driver blindly and put it in there to measure it just to build the crossover. I guess I figured you could model this before doing all that these days?
Hrm, in that case... what do you recommend that you think could be modeled prior to plan a build with the goal of 70hz~20khz range as a loud speaker and high sensitivity? I would be ok with trying to learn a 3 way design if needed. Most of the really sensitive things seem to be 2 ways? Would really just love something close to that 96~97db sensitivity range.
Very best,
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Some stumble into compression drivers and others do their research. Take your pick. If you want predictability then go with a dome.
If you want to start to get a handle on it look for a suitable horn that someone has measured (across different angles) and can verify will work with a chosen woofer. Then mounting it and measuring the impedance will just be a matter of course for you.
If you want to start to get a handle on it look for a suitable horn that someone has measured (across different angles) and can verify will work with a chosen woofer. Then mounting it and measuring the impedance will just be a matter of course for you.
Sounds good; sounds like a "do both" kind of thing. Practice modeling with a dome. Practice measuring with a horn.
Very best,
That's a soft cone resonance, and you can't remove it, and shouldn't worry about it.
I would worry about the stop band of the tweeter though, you need a zobel on it to control the response below crossover. There's also the matter of baffle radiation. If you cannot take measurements, use VituixCAD to simulate the baffle response and use that instead of the factory files, which would typically be IB or IEC baffle.
Since you can cross lower, I would move the crossover to 600 or 650 Hz. That would also fill in a bit of the woofer dip. Presently it looks like you have phase issues everywhere (very poor tracking) as the output keeps moving between the woofer and tweeter around crossover. You want something that looks closer, so always make your phase plots visible:
While there's no rule of thumb, I remember reading that you should target less than 90 degree of phase mismatch at 40dB down, to achieve coherence. While this is a very tough target, you can get close if the drivers work well together. Your situation is complicated by the very large diaphragms, but it might be workable.
I may have a look later - but it is not going to work well because the tweeter has effective output of only 85dB (the 92dB spec is not reached till 3.5kHz and is not valid for lower crossover points), and a different woofer is called for in a passive design. Likely this is meant to be used in active designs with DSP, given the poor sensitivity in the lower half of the passband and the slope of the top end. Not that it can't be done, but some choices need to be made.
Thanks for the detailed response; very appreciate. No worries, looks like I have the wrong drivers for what I'm doing. I'll try to look for new ones that I can model to at least learn on before I buy them to measure and learn that way too (would like to do both, one thing a time of course).
Very best,