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share with me some cab dim's

Discussion in 'Amps and Cabs [BG]' started by sbskates, Jan 3, 2005.


  1. sbskates

    sbskates

    Jun 13, 2004
    anyone built a cab 410 and 15 recently with currently available speakers willing to share correct dimensions?

    i have noticed gk's 115 cab and 410 cab are the same how i sthat?
     
  2. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    hey, stick all realated questions in your original thread - :p

    Really, get the eminence dimensions 1st. I suggested modeling after the swr/eden 410t before because it's very compact, but you still have to get real dimensions form eminence. FWIW, gk isnt the 1st company to do that. Eden's original 1x15 is the exact same external dimensions as their 410t. They said they did it so they would stack well. I'm guessing that companies that do this design or pick speakers that will work in the same size boxes. It's nice that they stack, (and i bet the company saves some cash by milling all of the boards the same).
     
  3. Marketing is what drives cabinet sizes, not an optimum match to a given driver.

    If you want optimum cab volumes, check my spread sheet. If you want an SWR copy, then make an SWR copy.
     
  4. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    so no offense intended BG, but are you saying that you're the only one who designs cabinets for optimum driver performance and all of the companies out there right now don't? Likewise, is eminence less likley to give proper cabinet requiremants for their drivers than you are?
     
  5. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    There are several common alignments (combinations of cabinet volume and tuning) for a given set of driver parameters. Eminence doesn't really tell you the cabinet volume to use, they tell you the specs you need to know, to discover the cabinet volume associated with a given alignment.

    BGavin's spreadsheet lists the cabinet volume associated with the most common alignment's for each speaker, based on the parameters for the speaker. They aren't designs; you can achieve the correct volume and tuning for a given alignment in any way you choose.
     
  6. sbskates

    sbskates

    Jun 13, 2004
    Thanks for the info!!!!!!
     
  7. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    gotcha, i was not aware that eminence did not include the cabinet volume in their info.
    however, while i don't disagree that some companies are market driven in their cabinet design, i find it hard to belive that none of them approach it on a more scientific basis.
     
  8. I built a 115 recently and you can see comments in my thread posted this evening.

    The spec sheet for the kappa15LF gave a suggested range of volume size. I decided on roughly 8000cubic inches after spending a long time tweaking in winISD , and deciding I didn't mind a larger box that was quite deep (tall, deep boxes I find easier to carry than especially wide ones).

    The alignments seem to be a paticular 'shape' to the response with associated tradeoffs in group delay, box size etc.

    I havn;t run tests to determine how accurate my planning was, and assumed all along reality could be rather different than the neat graphs in winISD, but the cab sounds as I expect so far.

    Part of the fun is the fact there are no 'right answers' only design choices and tradeoffs based on what your goals are - for a 115 do you want a deep sounding subwoofer type cabinet, or a bit louder more 'midrangey/upper bass' type cabinet? (for instance).

    MM


     
  9. Why?

    I spent a career as an engineer at IBM, and saw machines designed by salesmen, not engineers. Marketing had the final say on a design, and we produced a number of camels while trying to build a race horse.

    All commercial cabs are in business to sell product and make a profit. They all lie about their SPL numbers, because the biggest liar bags the customer. They all have to operate within a narrow price point, or they fail in the mass market. As Bill Fitzmaurice has pointed out here, there is a good reason why mass manufacturers don't build horn cabs: it costs them too much to make a profit. It isn't a lack of engineering, it is the amount of unit cost to produce engineered designs.

    It doesn't take much to slap a 4x10 together, size it the same as everybody else, then bullsh*t the specs with marketing to make it sell. Use Avatar cabs as an example. Measure the cab dimensions... funny how they are 3 sizes, yet accomodate all the various Avatar models and different drivers. Changing the baffle panel allows a 4x10 to become a 2x12 or 1x15. No regard is given to the completely different requirements of these drivers.

    Avatar Speakers could not sell at their current (low) price points, if he had to manufacture cabs correctly sized for each of the driver offerings. This would drive his cab costs and selling price through the roof, which would put him into the boutique league with Accugroove and the others. The Avatar designs are too weak to compete at that price point, and they would not sell.
     
  10. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    It is worth pointing out that in SOME cases, (not all) the difference in dimensions or porting is a tweak for sound purposes.

    While the tweak may be "inferior" if considered in a rigorous analytical manner, it still can have a sound advantage as far as the way the cabinet actually works in application.

    I used to design PA cabinets. It was a rare cabinet that didn't need something about the tuning, or the crossover "tweaked" to perform better. Generally this would result in something that the "numbers geeks" might describe as "non-optimum" and/or "inferior", but which actually worked better and sounded better.

    Now, there ARE companies which slap a speaker in a cabinet, port it however looks right, and go with it. That's different.

    I mean relatively minor tweaks, or size compromises. If you go too far you DO get problems, usually with tuning vs cone excursion, or vent noises, etc.

    The optimum cabinet is often too big to carry, or has some other such "user disadvantage" (good old Murphy..!). Sometimes the "optimum" cabinet per the numbers just doesn't sound right.

    In those cases, repeating "yeah, but its BETTER!" doesn't necessarily cut much ice with the folks who then DON'T buy it.........
     
  11. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    so does this mean that "accugrove and the others" (boutique league manufacturers) do approach cabinet building from a more scientific basis?

    Remember, you initially posted, "Marketing is what drives cabinet sizes, not an optimum match to a given driver." which is why i asked, "are you saying that you're the only one who designs cabinets for optimum driver performance and all of the companies out there right now don't?", and subsequently said, "while i don't disagree that some companies are market driven in their cabinet design, i find it hard to belive that none of them approach it on a more scientific basis."

    Don't get me wrong, I'm not trying to start anything more than a good natured discussion, but I'm unclear if you are trying to say that most manufacturers put the science after the marketing, or if they all do, and if you're saying that the design specs you share are superior to everyone elses cabinets, (from joe shcmoe's to accugrove and epifani).
     
  12. <sigh>

    I work in software development and our company is trying to create a 'market driven' approach to designing software, depsite the fact this approach seems unproven and we are overwhelmingly and engineering company (programmers and testers far outnumber the marketing folks). Why put your weakest team at the most crucial point?

    There seems to be a perception that engineers of all breeds don;t care about user requirements or the 'customer'. This imo is a trait of a bad engineer, and shouldn't tar all of them with the same brush. Its a shame when talented proffesionals get demoralized or frustrated because they can't focus on creating high quality products, with intitmate understanding of all the parameters (user needs, costs etc).

    Anyway I digress. Dipping my toe into speaker building and learning some of the basics of the physics and engineering approachs involved has been very rewarding so far and have this board to thank for getting me started and providing a lot of useful infomation. Education should never stop.

    Avatar cabs are really very cheap for what they are. In general, many pieces of technology are available to us now at prices that would have seemed insanly low 30 years ago, including speaker drivers and electronics. thats the impression i get - old timers feel free to disagree, i was a kid back then :)
    List prices in 70s' equipment brochures were not very low.


     
  13. Good natured discussions are neither accusatory nor hinged on emphasized semantics.

    :D

    If you are unclear then I suggest reading my comments once again. They are very clear and succinct, including the references to Accugroove. If you are curious about engineering vs. marketing, ask Mark at Accugroove. Or Andy Lewis at ACME.
     
  14. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i don't think i was being accusatory. i said i found it hard to belive that all companies didnt apprach cabinet building from a more scientific approach, and you asked why? then said that all commercial cabs are in buisiness to make a profit, and that they all lie. I'm guessing thatyou don't consider accugrove to be a commercial cabinet maker or a company.
     
  15. Don't guess. Take my comments at face value without attempting to read anything into them.

    :D

    Ask Accugroove about Accu-Switch. The web site marketing for Accu-Switch is nebulous and inconclusive. Patent-pending can mean a lot of things, including a 4-ohm resistor pack used to change impedance from 4 to 8 ohms. Ask if 600w at the input jack is 600w at the speaker terminals for both 4 and 8 ohm modes. Or, is 600w at the input jack actually 300w at the speaker in 8-ohm mode. This will explain why Accu-Switch is reported to be quieter at one setting and louder at the other. Mark doesn't have to tell you how Accu-Switch works, but he should be able to answer your question. If no, ask why not.

    Lying about specs is nothing new. It got to be so bad in the 1970s that a more stringent method was adopted to cut back the rampant lying. Does "program power" or "peak burst power" or “usable to 30 Hz” trigger a memory? These are marketing lies intended to inflate the capabilities of their products.

    For example, the wattage rating given to bass cabs is only an indication of how much current the voice coils will absorb before they melt into goo. The power rating has no bearing on the amount of power the cab will accept before the cones over-excurse into distortion or self destruct. Very few vented bass drivers will operate at full rated power without over excursing the cones at some point within the bass operating range.

    Another example is bass driver SPL numbers that are very often taken at unusable frequencies, such as 1 KHz, where the driver can accept the most power without over excursing. Most general purpose drivers make a lot of racket at 1 KHz and this hyper inflates their response numbers. In the usable bass range below 80 Hz their output totally sucks... but hey, look at those great specs. A response plot would show this as being pure bullsh*t, but very few manufacturers publish response plots. This exaggeration is called "lying" in my book. YMMV.

    Phil Jones is one engineer who actually publishes response plots for his products. If you want to see truly engineered products, then look at his works. Phil is an engineer first, and a marketeer second. His designs are much more than a product created by stuffing a few 10s and a tweeter into a generic-sized cabinet.

    All of this is significantly off-topic from the original question about cabinet sizes for a DIY project.
     
  16. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i don't see it as being that off topic.
    In any event, I understand how specs can be "fudged" and I don't disagree that some companies put marketing concerns before science when designing their cabinets. However, sweeping generalizations are just that. If there are companies that you feel don't put marketing concerns before science and don't lie about specs then say so. Or name which companies you think are honest manufacturers with well desingned cabinets and which arent. So far you've made a sweeping generalization, told us that avatar cabinets arent correctly designed for their speakers, said that accugrove is the "boutique league", that mark at accugrove or any lewis at acme can be asked about engineering vs marketing, that accugrove's marketing for the accu-switch is nebulous and inconclusive, but that i should be able to ask mark "my question", and that phil jones bass accurately publishes response plots for his cabinets and phil is an engineer 1st, and a marketer second. I'm finding your answers to my questions rather "nebulous" themselves.
     
  17. Let's cut the crap here... you are not asking questions, you are picking an argument. Big difference.

    If you don't like my comments, then don't bother replying to them. After all, they are just an opinion.
     
  18. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    not at all. essentially what i heard you say intially was that no one makes cabinets based on science, only marketing. So I asked if if that's what you meant, and if in fact you felt that all companies lied, and if you felt the designs you shared were superior to what is available. You've consistently refused to answer the questions. Instead you name drop without really saying anything and say go back and read what i already posted. I'm not saying you don't have a right to your opinions, far from it. I just think it would much clearer if were to state exactly what they are. If your opinion is that everyone's cabinets are market driven crap except for brand x, brand, y, and brand z, and that the designs you have are better than all of the crap brands. fine. just say it clearly. Instead you've been dodging clarifying questions in a manner that would put most politicans to shame. :rolleyes:
     
  19. Rockbobmel

    Rockbobmel Supporting Member

    I noticed that the Eden D 4-10XLT, the 2-12XLT, and the 1-18XL are all in the same box (Exception 1-18 has port blocks). It is my GUESS that they wanted to utilize that design for manufacturing ease, then had the drivers made optomized for the box's use, measured them and published the specs. The 4-10 has a nice hump in the low mids (I really like), the 1-18 is somewhat muddy, or wooly, and I have not heard the 2-12, but I'll bet it is in the middle somewhere... Another thing I noticed.,, Mesa Boogie used a number of different drivers in their boxes. The 15s and 10s usually were EV, but they had others at some time. It seems that EV makes only 2 types of 15s and one type of 10s, so are they "DESIGNED" for the boxes? Does Mesa make their boxes around the available EV at the time? I did see the new cutaway of a Mesa cab in the mags, and it looks like they did some really nice bridging/bracing and port work (3 different sizes) with their newer "POWERHOUSE" series cabs. I would love to hear one! So how SCIENTIFIC is it anyway?? This is just my prespective....
     
  20. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    I'm not sure if this has been made clear. These alignment designs are not Bgavin's; they are industry standards. Each of these alignments were developed over the years by engineers, and each one is the optimal solution to a specific design question for a given set of TS parameters (such as minimizing group delay, or maximizing low frequency extension).

    By definition, any other solution is a compromise, because each of the classic alignment is the correct answer to a single very specific engineering question.

    You can certainly argue whether a specific alignment is the best for bass guitar, but by definition they are "optimal" designs.