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any crossover nerds want to take on a mentee?

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  • any crossover nerds want to take on a mentee?

    In the far future, I'm looking to build the best crossover I can, but my knowledge is limited by my own definition (it is not non-existent). Strictly 3-way crossover. Yes I know there is a lot to know to make a truly great sounding speaker; I won't hold you accountable for any results. I have average-ish knowledge of DIY loudspeaker theory/design, I have the Dayton Omnimic and DATS V2, and a BSc in mathematics and physics. So who ever wants to really dish out the tech, I'm game. No, I cannot pay you, lol. Drivers will be mid-high-end-ish (of course that is all relative, but it's definitely not from the clearance corner, not that there's anything wrong with that, lol). Budget for all crossover parts is $300-$400ish, so I'm not afraid to get the good stuff.
    Last edited by guitar maestro; 11-09-2017, 04:34 PM.

  • #2
    I think most guys here will be glad to help! As a rule, all of us are smarter than one of us, so don't worry about finding a single person.

    Doing a 3-way as your first project is really jumping into the deep end. It can be done, but plan everything in advance, and still expect to have to redo a few things when theory meets reality. Just...set those expectations.

    I would start by defining your design goals, taking the room into account. That's a good place to begin. And for the love of all that is holy, do NOT purchase drivers until you run it past the crew here. There are lots of idiosyncrasies that may not be immediately apparent to you, but an experienced builder would pick out.

    If you get advice and the reason isn't clear, ask. We're all mighty proud of the things we've learned and we all want to see the hobby advanced, so you'll get no shortage of good explanation.

    Welcome to the club! Here's your robe. The kool-aid is on the table in the corner.
    nothing can stop me now

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    • #3
      If your not designing the XO, then it boils down to cabinet construction and driver mounting. Driver selection may need more experience with XO design that it appears.

      So what about a known design by one of the "Masters"?

      Comment


      • #4
        You have PM.
        Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

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        • #5
          Thanks Dirk. This isn't my first project. I've built 3-ways before, including the crossovers, but mostly as a teenager in the 90's (my first 3-way build was in '93 when I was 13/14 years old), using textbook formulas with no other equipment for analysis/verification (no money then). I simply want to "get back into it" with much better parts to begin with. It's not that I don't know anything and starting from scratch, far from it, LOL. The purchase of my new 3-ways has re-invigorated my interest to build something similar. Yes I know I'll have to buy many iterations of the crossover and many parts will be left over with no other use. I have no doubt I can learn some of the intricacies of crossovers on my own, but most of my time is spent working so I am hoping to get eventually "tutored" for my specific project so as to not waste time and what not. My time frame for my free time to work on projects ends up being spread out through out the year depending on my time off.

          Millstonemike, not interested in copying some other design, bit-for-bit.

          Some info/goals:
          • highish sensitivity (~95ish dB/2.83V/1m)
          • high output
          • relatively flat output from the mid-bass on up (I have DSP so I can always fine tune later especially for the bass section, but I do know that I want a relatively flat output based on my recent DSP'ing with my speakers)
          • amplifier (not purchased yet); will have "unlimited" power for this this specific project, so headroom will be plentiful (I'm thinking Peavey IPR 5000DSP or IPR 7500DSP, they're cheap enough, and I might have other uses for it other than this project)
          • I use Akabak for low-frequency enclosure modeling
          • I am dead-set on using AMT tweeters, I love their sound "character".
          • Tools and cabinet construction are not a problem. Sans a CNC router and machining center, I have every tool under the sun, including a small machine shop . And if I don't have the tool I need, I simply buy it.
          Potential Driver choices that I am contemplating (each speaker):This is the frequency response of my current purchased 3-ways after DSP tuning, so my goal is to replicate this (as best as possible of course). Mine are about 90 dB/2.83V/1m and are currently (and easily I might add) taking 400W RMS music signal courtesy of a Peavey CS800X, but I'm looking for more sensitivity and more power handling for more even more output.





          That's all for today folks. Thanks for the input.

          Comment


          • #6
            A pair of those RS subs in parallel (2ohms) only yields about 93dB, and that's w/out ANY baffle-step. The UM sub is yet a few dB lower.
            Your mids are pretty large to reach up to 3k (RT-5002, - beaming). Dayton's AMT goes much lower but rolls off on the top end.
            Why not 8" mids (or better yet, 6" - you can always MTM for greater sensitivity)?

            Comment


            • #7
              5002- I have used them. 2 is a bad idea, and they can only play down to about 3.4k before rolling off.

              I think the Beyma TPL-150 is your best bet, and they do sound very good.

              I also agree that your woofers are the wrong choice based on sensitivity alone.

              And I also agree that a 10" mid is not a good idea, unless you do go with the TPL-150. 8" mids would be better in terms of off-axis response, and an MTM arrangement would align the vertical dispersion rather nicely with the Beyma.

              Later,
              Wolf
              "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
              "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
              "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
              "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

              *InDIYana event website*

              Photobucket pages:
              http://photobucket.com/Wolf-Speakers_and_more

              My blog/writeups/thoughts here at PE:
              http://techtalk.parts-express.com/blog.php?u=4102

              Comment


              • #8
                Originally posted by Chris Roemer View Post
                A pair of those RS subs in parallel (2ohms) only yields about 93dB, and that's w/out ANY baffle-step. The UM sub is yet a few dB lower.
                Your mids are pretty large to reach up to 3k (RT-5002, - beaming). Dayton's AMT goes much lower but rolls off on the top end.
                Why not 8" mids (or better yet, 6" - you can always MTM for greater sensitivity)?
                Absolutely correct. Which is why I specified my flexible goals. Not looking to do MTM. I am looking at the 10" midbasses due to additional power handling, and many of those can reach 3k on the top end.

                Originally posted by Wolf View Post
                5002- I have used them. 2 is a bad idea, and they can only play down to about 3.4k before rolling off.

                I think the Beyma TPL-150 is your best bet, and they do sound very good.

                I also agree that your woofers are the wrong choice based on sensitivity alone.

                And I also agree that a 10" mid is not a good idea, unless you do go with the TPL-150. 8" mids would be better in terms of off-axis response, and an MTM arrangement would align the vertical dispersion rather nicely with the Beyma.

                Later,
                Wolf
                Wolf, as I mentioned in the DIY audio thread, the low-end would be somewhat dependent on the reference sensitivity one chooses to implement. If you notch the entire output down to a baseline of say 88 dB/1w/1m, (just as an example) then the passband would then seem like it "goes lower". Well that is what I might end up doing. Just not down to 88 dB, that was just an example.

                Based on the .frd file I found for the 5002, if I were to decrease the sensitivity down to about 94ish dB, then it "appears" to go a lot lower than 3.4k. Granted, yes I know that it does not actually impart the power handling capability. I know power handling would decrease a bit, but maybe two would take care of that, if I even choose to use it. I know you feel that is a bad idea, but it can't be the first time anyone in the history of the world has implemented two tweeters in a loudspeaker. These are clearly not going to be used for critical record studio mastering monitors.


                I am not basing the bass drivers on sensitivity alone. I know they bass drivers won't keep up watt-for-watt, but that is what DSP is for. I don't mind boosting up the low-end to make everything match up nicely, hence the very power amplifier choices I have in mind. I'm not asking for driver selection help, although I will read and consider any wisdom you may want to offer. I'm asking for crossover help, hence the name of the thread. Off-axis response is not a huge problem for me. Perhaps you are looking too much at your own criteria, and channeling into my project. It's just not necessary.

                If you feel you cannot offer crossover help, then that is totally ok. You don't have to feel bad if I blow my money on something that you feel will not work. Your wallet will still have the same weight before-and-after any project I choose to embark on.


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                • #9
                  You said you wanted this to be passive, am I right? And no- I did not know you were the same person as over on DIYaudio as your screen name is different.

                  The disconnect here is you stated you want it to be passive. Most of us are going to recommend how to do this without EQ or DSP usage. If you are doing that then you are changing the rules before we help you roll the dice. I see that you are wanting to use a stereo amp of one or another with integrated DSP. Why don't you just go active and solve all of your problems? You wouldn't need any of us.

                  You say you want xover help, but without the driver basics and what you are going to do exactly, it's hard to tell what we should be helping you with. We have to know what drivers you will use- EXACTLY- if you are going passive. There are not any substitutions, or any other criteria to make one driver apply to a system that the system was not designed for. This is why the detail and background we are asking is being discussed. If we help you design an optimal passive xover for your particular drivers, the DSP is just not necessary. This is how the process rolls.

                  If you don't want input on drivers, then this all may very well be a wash if you aren't going to tell us which ones you will use for certain. You can't have xover help without given drivers.

                  I'm not looking at my criteria, I'm looking at what little you have supplied.

                  Now- do we understand each other? No need to help if you are not going to listen.
                  Wolf
                  "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                  "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                  "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                  "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                  *InDIYana event website*

                  Photobucket pages:
                  http://photobucket.com/Wolf-Speakers_and_more

                  My blog/writeups/thoughts here at PE:
                  http://techtalk.parts-express.com/blog.php?u=4102

                  Comment


                  • #10
                    I think you're confused, a "mentee" follows the advice of the mentor while learning in the process. I think what you want is an employee whom you do not pay.

                    Comment


                    • #11
                      I'm not needing the help this very moment, since as you can see I have not explicitly chosen the drivers as of yet. And no, I'm not confused at all, dld. You're assuming the mentee is without any resource what so ever and is all but helpless without any mentor, which is not so. Wolf, I don't have any problems,lol. This is just a project I decided to tackle just for the hell of it, not in the immediate future, but just sometime in the future, maybe 3 months, maybe 6 months, maybe a year. Perhaps I should have worded things differently: I would like some crossover help when the time comes, only from those willing to offer such help. There, we can all relax now and carry on without worrying about this thread. It's not like I'm sitting here with a soldering iron wanting for people to tell me exactly what to do or else jigsaw will end my life as part of his cruel games, lol. Perhaps everyone thought I have this project on the burner right now and am stuck without anyone's help? Not so, lol. Thanks to everyone for your input.

                      Comment


                      • #12
                        Based on your moniker ( & all the Pro 10" mids in your list ), is there any chance you're thinking of using these for live gigs ?

                        Comment


                        • #13
                          Originally posted by EarlK View Post
                          Based on your moniker ( & all the Pro 10" mids in your list ), is there any chance you're thinking of using these for live gigs ?

                          Nah, I play guitar just for fun, taught a couple frat brothers in college the basics of guitar, and I ended up using that username on some audio forums here and there, after they called me that around the frat house for a little bit. Now a days, if I register on a forum it's usually just Oscar.

                          Comment


                          • #14
                            I'd recommend adding the Eminence Deltalite II 2510 to your list of possible Pro mids.

                            It's used by some ( such as DIYSG ) with great success in the HT world ( and a bit of HiFi by Troels Gravesen ).

                            Comment


                            • #15
                              We paired the Acoustic Elegance TD10M with the TPL150H in a beast of a monitor crossed at 1000Hz. The passive XO for the TPL took a few parts to EQ the response to flat but the result was superb. Flat response from about 60Hz on up. All it needs is a sub and you have something capable of very high SPL with minimal power.
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