Using WinISD for Traynor TS-215 mod

Discussion in 'Amps and Cabs [BG]' started by shrugs, Jan 7, 2022.

  1. shrugs


    Oct 22, 2017
    Hey everyone, first post here! I've got myself a Traynor TS-215 ported cab just like the one here. I've read through that thread a million times and I've decided I'd like to modify it. The cab works absolutely great with the matching 50W Traynor TS-50B head, but the cab is only rated at 80W, and I'm going to be using it as a backline cab for my DIY space, so ideally I want to maximize the cabs power handling so someone can bring their overpowered head, plug it in, and they wont blow up my cab. I want the cab to be rated at a 4 ohms load since virtually every bass amp will work at that impedance. There will be plenty of loud and down-tuned punk/metal music played in the space. Ideally I would like a tuning frequency of 55Hz as this is the second harmonic of a 5 string bass with the lowest string tuned to A0 (27.5 Hz) which is common for these genres. Maybe it's not the best cab, but it's what I have.

    I went ahead and grabbed a pair of Eminence Legend CB158 8 ohm speakers (maybe prematurely, we'll see) since they are highly regarded, have a high power rating, and Eminence claims they are suitable for vented enclosures. I manually entered all of the T/S parameters into WinISD and I got the green light saying that the driver was good to go. Nice! I went ahead and created my first WinISD project.

    The cab has an approximate internal volume of 6 ft^3. There are two port holes with a diameter of 3.5" and depth of 3/4" (simply a hole in the plywood baffle). According to WinISD, this simple won't cut it. I'd get horrendous chuffing, terrible power handling, and a tuning frequency that's way too high (I think around 100 Hz?). Where I'm at right now is considering my variables.

    Do I simply maximize the number of ports I can possibly drill in the baffle? The more ports I create, the higher I can crank the System Input Power before I hit 17m/s port air velocity. Correct me if I am wrong, but I've gathered that this is the threshold before chuffing starts. I can fit a maximum of 6 ports on the baffle, and at that number, the depth of each is 6" which is fine (cab is 13" deep), and the highest power I can put into it is 450W. That sounds pretty good to me. Is this overkill?

    I have some wiggle room on tuning frequency and I could buy different drivers but I'd prefer not to at this point.

    Ok let's check the cone excursion. Well, I cross above Xmax at 44Hz, and I cross above Xlim at 36Hz (the graph skyrockets below 36Hz). My transfer function magnitude graph says that at 44Hz I'm already down -9.8dB, and at 36 Hz I'm down -14.8dB. My f3 is about 59Hz. Do I need a high pass filter here? I could build one, I have the soldering skills and could source the parts if necessary, but of course I'd rather not. Robustness is part of the plan though since the amp head is a variable here.

    Ok let's check SPL... 129dB peak. This is where I get a bit lost. I googled that number for reference and it said "threshold of pain" is 130dB. Well if I don't feel pain when I take my ear plugs out, it's probably not loud enough for this genre. Is this a realistic number? Did I miss any key features here? Does all of this look savvy? Looking for someone to give this a review.

    My last question is: how do I connect a PVC pipe to the back of the baffle to increase the depth of my ports? A mess of epoxy? Some sort of L bracket? I'm worried that if the connection is not sturdy enough, the PVC would vibrate itself loose. Is there something I should use besides PVC? Does PVC even come in 3.5"? Doesn't seem to. Should I drill all the ports to 4" diameter and recalculate just to make finding PVC easier? Looking for tips here.

    Thanks in advance!
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Why not get a cabinet already more suited to your needs? Once you are done, your cabinet will have nothing in common with the original cabinet except that it’s made from plywood.

    You need to stay way away from Xlim, by the time you reach that you are already damaging the driver.

    I think your expectations are greater than what your project will be able to deliver in any regards, yes IMO whatever amp that’s going to be used should have a HPF set at about 40Hz assuming a fourth order BW filter.

    I would also suggest verifying that the results you get from the software are correct.
    Last edited: Jan 7, 2022
    DJ Bebop, shrugs, Murch and 1 other person like this.
  3. shrugs


    Oct 22, 2017
    I figured this would be a good learning experience for me, and I love the Traynor aesthetic. I don't mind that these changes will completely change the tonal qualities of the cab. I figured doing these mods would be cheaper than buying a cab, especially when shipping comes into play. I've also found it difficult to find cabs that tell you their tuning. Do you have recommendations for what I'm looking for? I'm open to suggestions.
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Post your graphs.

    Good used 215 and 410/810 cabinets are the bargain of the century if size/weight aren’t an issue (given what you are doing, it’s not). You can usually find them locally for a few hundred dollars, about the same as you spent on drivers and shipping.
    DJ Bebop, shrugs, Murch and 1 other person like this.
  5. OP,
    The tuning frequency is somewhat "tourist information", as it is more of a road sign for your needs.
    The 2nd harmonic is another red herring.. just pay attention to the fundamental of your instrument for this design.

    #1 - determine the lowest note you will ever put through this cab.
    You don't care about vent velocity or cone excursion below this frequency.

    WinISD will let you fiddle with the volume and tuning frequency.
    Cone excursion is always the limiting parameter here... not how many watts the voice coil will absorb before melting into goo.

    Take note of cone excursion both Below and Above the tuning frequency.
    Nowhere should it exceed Xmax... as noted above Xlim is the mechanical damage point, and bye-bye driver.

    CB158 is a loud and efficient driver (EBP=95)... it requires a large cabinet volume.
    Squeezing a pair into 6 cubic feet is emasculating this driver, and it will perform accordingly.

    If you stuff two of these into 6 cubic feet (3.0 each) and tune at 55 Hz, 175w per driver will take you to the upper Xmax limit. A strong high pass filter above 40 Hz is mandatory at this power level.

    This will give you a bump in the 70 to 200 Hz range and a strong mid-bass.
    Two 4" PVC Sched40 (3.998" ID) will keep your vent velocity in check at max power at the HPF point and higher.
    shrugs and agedhorse like this.
  6. shrugs


    Oct 22, 2017
    Here are my graphs: ts-215-air-velocity-signal.png ts-215-cone-excursion-vents.png ts-215-SPL-box.png ts-215-tfm-driver.png

    NOTE: I re-measured my cab and it comes out to 6.21 ft^3. Probably wont make much difference, just wanted to point it out. On the SPL graph, the line goes way above the window and I am unsure how to resize it in WinISD, so I put the cursor on the peak, which is 128.68dB.

    I'll keep an eye out for sure, there isn't much on the used market for 2x15s or 8x10s right now in my area. You're right, I don't plan on moving the cab. I can only really look for cabs that haven't had their drivers replaced, cuz then who knows what the specs might be at that point, and their hard enough to find on stock cabs. I prefer 2x15" over anything else. 4x10" are too short and not great for self monitoring, unless I elevated it somehow. Typically the punk/metal guys wanna hear that "clank" in the 800Hz - 2kHz range pretty well, which can be tough so far off axis from the cones when they're so close to the floor.
    agedhorse likes this.
  7. shrugs


    Oct 22, 2017
    Thanks for the info bgavin. The lowest note that will ever be put through this cab is A0 which has a fundamental frequency of 27.5Hz. Is this what you suggest I make the tuning frequency?

    After going over my frequency response graph, I'm realizing this is pretty terrible for the genres that I'm playing, as the guitars are down-tuned as well and typically love that 120Hz palm mute chug. The guitars midrange is often scooped a bit to let the bass through in that region, and of course the bass should come through below 120Hz as well. I'm not at all married to the 55Hz tuning, that was something I found suggested on one thread here. Consider the 6.21 ft^3 my constant here, and pretty much everything else is a variable.

    Do you think this is lost cause and I should just buy a different cab? What do you suggest here?
  8. Dino Boreanaz

    Dino Boreanaz Supporting Member

    Feb 25, 2018
    Toronto, Canada
    I used to own a TS-215 and modeled a few different drivers in it before deciding it was simply too large for my use and selling it. I thought the Eminence Legend CA154 modeled nicely in this cabinet, with decent low-end extension, good power handling, and without the peakiness around 100 Hz that many other drivers showed. Having said that, I have no experience with this driver and never actually tried it out. In fact, based on the frequency response curve from Eminence's website, it likely doesn't have as much high-end as many other drivers, so it may not be useful without another driver to carry the high end, but the model was encouraging.

    I think there is some danger in having applications like WinISD available to amateurs like me. The model may look good, but without having a way to validate whether it's actually correct, and not having first-hand knowledge of the tonal characteristics of the driver, it's probably too easy to make a decision and spend money only to get disappointing results. I do still play around with WinISD, but I don't put absolute faith in the plots generated.

    As for re-sizing the plots, you can click on the wrench icon at the top of the screen to open the options menu. Select the "Plot Window" tab and you can enter the upper and lower limits for each different graph. This should allow you to get the entire plot within the viewable area for all graphs.

    Lastly, on the topic of tuning frequency. I don't think it's necessary to choose a tuning frequency based on a specific note, but rather (like @bgavin stated) change it to whatever value keeps the cone excursion below Xmax across the entire expected frequency range.
  9. Yes.
    The HPF will cut everything below 40 Hz to protect your drivers from over excursion.
    Whether or not you NEED A0 is subjective, especially in a live mix.

    *If* you were a solo player, on an instrument that actually produces the A0 fundamental at full strength, it might be different. I play solo this way with a digital 88-key piano and want the full range without conflict with drums or other instruments.

    One solution is a vented LAB12 in 3.6 cubic feet at 23.5 Hz, F3=24 Hz.
    This is a Flat alignment, but LAB12 does NOT make a whole lot of noise.
    This is a subwoofer that crosses over at 100 Hz to a full range top box.
    I use a Crest ProLite 3kw dual channel amp with built-in L/R crossover at 100 Hz.

    If you truly need to go both Low and Loud, you require multiple subwoofers to reach A0 at any intensity.
    This is a lot to pack and haul around, and a whole lot of investment, so make damn sure this is truly what you want before taking the leap.

    All of this is highly specialized (read: expensive), both electronics and speakers.
    shrugs likes this.
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    You could lengthen the ports by about 25%, lowering the tuning a bit, but I don't think this project is going to get you to where you think you need to be.

    The tradeoff to lower tuning is a little more displacement of the driver and a little lowering of the power handling. At this point, I don't think you are going to need to worry about port noise, and you will certainly need a HPF.
    shrugs likes this.
  11. shrugs


    Oct 22, 2017
    Hey bgavin, I chopped up your quote a bit just to keep the parts I want to address.

    I do not think I NEED A0 fundamental, which is why I initially went with a tuning of 55Hz, because then I could have a healthy volume of the 2nd harmonic of A0. The 2nd harmonic of a (bass)guitar string is usually louder than the fundamental anyways. I certainly need to go "loud" as these are loud genres where the drummer hits very hard and the guitars are heavily distorted. Guitars go down to about 120Hz maaaybe 100Hz. I just need the bass to be nice and audible below that palm mute point, which leaves me with a range of 55Hz - 120Hz where the bass would not be masked by guitars (let's ignore the kick for now since in this genre it usually sounds more like a click at 8kHz than an actual bass drum). If I can get a somewhat linear response in that range, at somewhere hopefully around 300W or above, I'd be satisfied.
  12. shrugs


    Oct 22, 2017
    Do you have any bass cabinet recommendations that are 300W minimum, 2x15" configuration, and tuned low enough to hear an A0? It doesn't seem like I'm going to get the power handling I need out of this cab if I want it tuned without a push at and above 100Hz, although it's only big a deal can that be?
  13. wcriley


    Apr 5, 2010
    Western PA
    Paging @Foz to recommend a fEARful 1515/66.
    Bill Whitehurst likes this.
  14. shrugs


    Oct 22, 2017
    I've considered building a fEARful before! Lots of work but I'm sure it pays off. Are there any production cabs that are similar?
  15. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    I can’t recommend specific cabinets, but if you look around you will see an assortment.
  16. And bumble bees cannot fly....
    There are lots of urban myths in our world... and I have signal analysis that show the above is B.S.

    I would suggest you borrow or rent a quality wireless for your rig.
    Stand out in front at the audience position while the band is playing.
    Stay there for an entire set.. and move left and right to hear your rig sound when off-axis.

    What you hear on the stage is very different from what is heard in the audience.

    I assume you are a new bassist... this is NOT a dig or a diss at you... everybody starts out with the same questions.

    Everybody wants to hot-rod their rig into something better, even though engineers like Agedhorse have long paid their newbie dues, and work hard today to create quality rigs that actually work properly.

    The real trick is finding out what YOU want in your sound.
    Once you know what you want, finding it is easy... because it DOES exist.
    I don't want to see you piddle away a huge mount of $$ and labor to find the 1,001 types of bass rigs that don't work for you.
    Murch likes this.
  17. shrugs


    Oct 22, 2017
    Good to know! Thank you, I was just going off of what I've read. Never done the analysis myself.

    The space is pretty small, I already do this often with a long cable. I know what sound I'm going for in my head, and I already get close to that sound out of my current rig, especially on the treble end. I don't really know what that looks like in physical cabinet form. The main objective of this thread is for robustness and not blowing speakers. I want a cab that can handle 300W or more, and one that goes deeper than my current cab.
  18. OK to get robustness and go down to 27.5 Hz I think you will find that the limiting factor will be not cubic feet but cubic dollars.
    FOZ should be along shortly to point you at his answer to that. :thumbsup:
  19. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Or both?
    wcriley likes this.
  20. OP don't get carried away with the A0 or whatever. The CB158 is a great sounding bass guitar driver and you've made a good choice. Look at the medium vented cabinet design for it at Eminence's website. It's about half the size of your cab, and you have two drivers. (Convenient...) Tune it to 50Hz as per the design and you will be very happy.

    Remember, the king of bass cabs, the 810, rolls off at 70 Hz but nobody complains there's no bass.

    You're good.