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First Summer Project - finally a decision on drivers.

13

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  • I am hoarding my single malts currently. The 25% tariff has really driven the value down. Sticking with beer lately.

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  • Here is an Ebay link to the port tubes I am using on this project:

    https://www.ebay.com/itm/332058563702?hash=item4d503b9476:g:LHoAAOSwp8pbuXZd

    I think they look cool, in a perfectly cheesy way. Paint should be cured enough for handling by tomorrow so I hope to get initial measurements taken.

    kenrhodes
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  • Dimples are all the rage this year.

  • I like them, other than a mild irritation of the driver diameters not flowing.

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  • Calling these "outriggers" is pretty much a blatant lie, just FYI.

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  • Not so out riggerish at all. 🤦🏻‍♂️
    Speakers are coming along nicely👍🏻

    jr@mac
  • Yeah, wtf no out rigging going on there. Maybe lose the spikes?

     John H, btw forum has decided I don't get emails
  • Another fine product from Dayton... I feel like they roll the dice on products and expect us to fix their lack of engineering and design. Outriggers should be pretty easy.

    rjj45
  • FWIW, these have been in stock at Solen for a LOT longer than PE has had them. Same exact product, different packaging. They were a door prize from Solen way back when InDIYana was at the Hyatt Place, and I felt as you all have stated back then.

  • Well, so far so average. The Dayton tweeter really is an obstacle. I've commented before, but it bears repeating. The corner freq of the waveguide pretty much coincides with the drivers Fs. This really makes it difficult to shape the response in the bottom end - and since it is a high Q driver, it is already peaky at Fs which is amplified by the mechanical boost etc. I just wanted to use up drivers, it's the only reason it is in this design. If I were starting from scratch, I'd likely pick that Peerless/Tymphany/Vifa/whafuckever little waveguide tweeter. As it is, I'm going to live with the slight harshness this tweeter brings to the design.

    I've been measuring/voicing since yesterday afternoon. About ten hours total, would have been more but I needed a beer break last night.

    Anyways, budget is as budget does. All three drivers seem decently matched from a quality standpoint and I pulled off a pretty simple crossover containing eight components.

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  • Some in-room fun with Lindsey Sterling:

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  • Just a fun observation. I ended up (so far) with a 20awg, 2mH coil on the woofer with 0.8DCR. The top image is my modeled in-box impedance, the bottom is the system impedance (the wrinkles above resonance is probably partially from the wires I have in the port, and who knows what else).

    The tuning was predicted very closely by WinISD. The magnitude of the impedance was not correctly calculated, but since we do not use WinISD to generate design files that is ok.

    I've got some more listening to do, I really need to be certain these qualify as average enough with the simplified crossover. I am trying to listen to them as someone else, and it is hard to disengage critically sometimes.

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  • Oh, and the bass is legit af on these. Damn.

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  • What are your impressions on the dome mid?

  • To be honest, not much. It is alright, but be prepared to do extensive work if you want to use it in a high output system. I figure in this design, the woofer will run out of poop before the mid so I feel relatively safe with a simple 1st electrical low and high pass plus series resistor. If you are considering it as the middle of a budget 30way with, say, the MCM 8" woofer you may want to throw an LCR notch on it and go with a 2nd electrical, probably 800 or 900 Hz.

    The top end is a total pain in the ass to work with, at least on this baffle.

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  • That's too bad. I'll push my pair to the back of the shelf.

  • OK, hell with it - I am done with these. I am officially at the stage of trading one flaw for another and it just isn't worth pursuing any further.

    So, without further ado...

    Here is an on-axis and reverse null measurement. These are taken approximately 1M, SPL is accurate, so I was stressing the system. Taken on the tweeter axis. I will do some more extensive measurements at another time, after I get the crossovers soldered up.

    Read into what you will - but the reverse null measurement shows good phase at that point in time and space. The on-axis has a broad, semi-shallow dip from 1800 to 4000, and then a slow drop off starting around 7500. The dip between 1800 and 4000 was a deliberate design decision because I like how it sounds, and it likely fills in off-axis.

    Here is a distortion measurement, same conditions as above.

    The peak at 380 was not there at a slightly lower volume measurement, other primarily 2nd order dominant. The dip at 200 is floor bounce. These hold their composure fairly decently until a little over 91db, at which time things get ugly. Then again, a little over 90db is where our ears start suffering as well.

    The crossover:

    Simple. I would not use this midrange like this if I was crossing to a woofer that will play stupid loud. For example, if this was a sealed satellite and I had a subwoofer to cover below 80Hz, I would cross the mid higher and with a steeper electrical filter. At what I consider normal, safe, and sane listening levels this midrange does just fine crossover as simple and as low as I did.

    Here are the in-box measurements:

    Welp, time to solder.

    6thplanetkennyk
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  • Could the peak at 380Hz in the distortion graph be a port resonance?

  • It is indeed. I took port nearfields earlier today. I'll retake after crossovers are installed and the wires are no longer coming through.

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  • Just shit for posterity.

    kenrhodesrjj456thplanetJasonPkennyk
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  • I'm putting together a BoM for this - and I gotta say, the Parts Express website really, really, really sucks for this kind of thing. It is very slow, and I still hate the stupid sliders that are supposed to be some kind of filter. Just... slow, clunky, and irritating.

    That is all.

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  • Oh no! Not an unfinished bottom?!?!

    rjj45
  • @PWRRYD said:
    Oh no! Not an unfinished bottom?!?!

    Glad someone caught that ;)

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  • We are always looking at your bottom. :3

    jr@mac
  • So, a BoM for this project. Couple notes: if someone were to be able to source the woofer this is otherwise a viable project.

    The knockdown cabinets, perf boards, and some other odds and ends really drive the cost of the project up higher than it is likely worth. I just wanted the shelf space back, and the size factor of the knockdown towers is not ideal for too many projects. I find them too short.

    Anyways, I have two columns of cost - one column if you do not own anything and have to buy a bunch of stuff, and one column calling out the cost of dipping into inventory if you already own a bunch of wire, terminals, etc.

    According to this quickie chart, my "consumable" cost was almost $40 on this project - not counting the self-adhesive felt I bought as gasket material, wire ties, hot glue, two-sided Gorilla tape, solder, and the paint I used to cover things. Some corners can be cut by using scrap wood as crossover boards, buy a huge roll of a single color of wire and use other means to identify what lead goes where, inexpensive terminal cups instead of binding posts, solder all connections instead of using crimp terminals, using Walmart polyfil, using cheaper port tubes that still get the job done. There are a lot of ways to drive project cost down without adversely affecting performance. In this case, the only items I did not already have on the shelf depreciating and gathering dust was the $5 package of felt I bought. Every single item I otherwise used has been doing nothing but reminding me how much money I spent over the years building inventory - so I am not all bothered by the fact I spent way more on the project than I would have if starting from a blank sheet.

    The reason I am providing this information is to give people who may not know how much it actually costs to enter DIY at least one example of why it might be worth buying only what you need versus buying a shitload of stuff because you might use it some day. I am also pointing out that finishing a pair of speakers with what I consider the bare minimum quality (see my list of alternative hardware above) can cost what a pretty nice driver can cost.

    Lot of hidden costs in our hobby, and I know most of us intuitively understand that - but the kit buyers may not quite comprehend how much our grassroots R&D is saving them - especially with the affordable CNC cabinets being offered for several kits. Even a cheap table saw costs what the pair of flat-packs I used in this project - and having spent several years trying to get quality cuts out of one of those small hobby saws I think I can say it is probably not worth trying to build anything that needs to look great using a saw like that if you value your time.

    Time: all in I have around 20 hours in this project. Woodworking, measurements, voicing, soldering, etc. If it was a kit - it would take perhaps three hours total work across two days. I understand the appeal of the kits, but just not for me. I figure the CNC flat pack saved me, overall, an hour of table saw work. Now that I have a decent saw, anyways. Still getting used to that - that these budget projects should not utilize the flat pack kits. On the other hand, had I not gotten an insane deal on the bigger table saw...

    kennyk
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  • edited April 2021

    This is a great post JR. I know that I frequently lie to myself about how much I spend on this hobby. Guess it doesn't hurt so bad when one night on the way home from work I pick up $7 worth of allen head cap screws and T-nuts... a couple of days later I stop and buy a gallon of Titebond when out grabbing something for lunch. On a side note, when you're really into this hobby and building more than one project per year the costs go down because 1 gallon of Titebond might build ten or so projects (guestimate).

    With all that said my big take away from your BOM post is that I probably should focus on building projects with mid to high performing drivers. Seems like all the little stuff adds up regardless and makes using better drivers overall worth it. I started realizing that when placing PE orders for crossover components for cheap driver 3 way projects.

    Even so, overall this hobby is way cheaper than trying to be competitve in a drag racing, heads up, street class. Or maybe even golfing. You can buy some pretty kick butt drivers for the cost of a few rounds of golf with a cart. Or going to those off track gambling places. Not that there is anything wrong with any of that... just saying 🤪

    rjj45kennyk
  • I agree strongly with PWRRYD - a few years ago I realized that the biggest expense in this hobby for me was all of the time I require to churn something out. I could move a lot faster, but then I wouldn't enjoy it so much! But that means for me I am using more and more high quality drivers and components in my designs.
    One of the things I refuse to consider is the original price I paid for a driver. If it's been on my shelf for 5 years or longer, the effective cost of it is $0 as far as I am concerned.

    JasonPkennyk
    But Chahly - Stahkist don't want speakers that look good, Stahkist wants speakers that sound good!
  • I'm not arguing for or against budget designs here.

    I was just pointing out that we tend to ignore costs when building speakers. It takes a long time to amortize a garage full of tools to where the cost is minimal contribution to a design. For a typical table saw, the tenth speaker we build could still has over $50 worth of table saw cost sunk in it. Granted, quite a few builders segue into DIY audio from other woodworking related hobbies so the cost is not universal. For those of us who have bought the majority of our tools to support DIY, the cost is significant. I could have bought a pair of pretty nice Revel speakers and been done with it. The time I spend on my hobby is healthy time, regardless of project cost - so I never feel I could have spent that time better. I do not personally distinguish between different projects, as I am definitely a process oriented guy. However, if the goal were simply to get a really nice pair of speakers, again - a part time job plus saving the money I have spent on the hobby in general would have yielded a pretty amazing pair of commercial speakers. Having a great pair of speakers to listen to every day is secondary, possibly even tertiary, to the primary reason I DIY.

    I have lost count how many designs I have built, but I imagine my tool cost is still in the $50-80/design range. Plus, the drivers I have bought that do not end up being used for whatever performance/aesthetic reasons are part of the cost of turning out a design. It adds up.

    I guess basically - whenever I see a BoM published for a DIY design I get a little bothered because I think of the sheer amount of money not captured in the usual DIY BoM. Not mad or anything like that, and I am not at all obsessed - but in the interest of letting potentially new addicts what they are going to get into I feel I must point it out from time to time. If someone is only interested in building a pair of speakers as part of a DIY bucket list, they may be better off with a kit or having someone cut and machine the cabinets for them. Of course, they may also want to jump in with both feet and go to town. Only the individual can determine what is and is not the right approach - but some availability of data indicating how expensive it actually can become to build a pair of speakers might allow someone to make a better decision on how they value their time and money. I think of the time I bought a 3/4" roundover bit to finish a project, and remembered thinking "wow, I just added the cost of a better pair of tweeters to this project". Incidentally, this is why in many of my earlier writeups on budget speakers I would address my baffle edge treatment decisions - fully understanding not everyone is going to be able to afford a $30 router bit or have the motivation or even ability to make a circle jig (much less spend money on a Jasper) to countersink drivers etc.

    All that being said, I maintain a simple intellectual interest in project costing - I am personally going to build the project regardless of cost of any one or more components within the proposal. I start with an objective and build backwards from there, and it is not all that often that the objective is "use driver X and Y". I generally start with questions like "Have I done an 8" 2-way with a large ribbon? Can I?". I then proceed into research into drivers to see what drivers may be available that will meet the goal (Yes, I can). Other times it starts with "I want a small form factor tower that will play anechoic to 35Hz - what does that take?". This might be why I cycle through so many drivers - I impose a marketing demand and engineer towards it. I guess I might have more in common with the commercial guys than I think. That approach is, for now, partially on the back-burner as I am primarily concerned with reducing inventory at the time. Once I feel my inventory of drivers is sufficiently small I will re-evaluate the direction I want to take things. My gut tells me I will start knocking together budget designs again, just to be able to afford to try a lot of different design concepts. My intellectual curiosity is still very strong regarding DIY, but my current crop of projects (there is a third in the works right now as well) are literally just "make space, you dumbass" projects.

    As I've been known to say from time to time: "DIY for the sake of DIY". We all DIY for our own reasons, and we all have the luxury of defining our own limits, our own rewards, and we reserve the right to change our minds and our motivations.

    So keep building brothers, and enjoy yourselves - it's later than we think.

    JasonPrjj45Turn2kennyk
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  • I guess I'm a bit different in my thinking, if I need a tool I usually just buy it. In my mind it's a means to an end. I need it to complete the task, so I buy it, needless to say $50 per build, would not cover my tool cost. I also try to stay away from the cheaper tools, because every time I cheap out, I get burned. But on the other hand it can be fun to see just how much performance you can squeeze out of some cheap drivers. Everyone has a different budget, and what I consider to be an expensive driver, may be someone else's cheapie or vice-versa. As you alluded to JR, in the end it's all about having fun.

    jr@mac
  • When I started buying tools, I couldn't afford better stuff - so I made do. For the most part now, my tools are generally prosumer grade or better. I would have bought fewer but better tools back then if I had it to do over.

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