m00n Posted January 4, 2005 Share Posted January 4, 2005 I just took the 12" driver off the cabinet to measure the size of the MDF they used. It was only /12". Hence my question. How much of a difference to the overall sound of the speaker will it make when I rebuild these if I go up to 3/4" MDF? Also, I realize that when I measure, I'll need to measure the inside of the cabinet to make sure the volume inside stays the same... Other than that, are there any other issues that I could come up with? What if I wanted to change the physical nature of the speaker? Are there any free easy to use and understand cabinet apps out there that can take the size of a current speaker, determine the volume, allow me to plug in new dimensions to come up with differnet shapes but keep the same volume? Thanks all. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted January 5, 2005 Share Posted January 5, 2005 M00n, if you use 3/4 inch mdf, just build to the same internal dimentions. To figure the outside dimentions, add a 1/2" to all measurements. You did not say that the speakers are sealed, or ported. If they are of a sealed or closed box, then you can be a slight percentage off the volume internally+ - 5% without affecting the sound too much. If it is a ported design, then there is more precision involved. You may also consider bracing internally, depending on the size of the enclosure ( the larger the panels, the more the tendency to vibrate and color the sound ). Quote Link to comment Share on other sites More sharing options...
michael hurd Posted January 5, 2005 Share Posted January 5, 2005 To figure out the volume of a simple rectangle, take the internal length, and times by the height and also the depth to get the volume in cubic inches. If you plan on changing any measurements, then run the math again to figure out if the volume has changed that much. Again, with a sealed enclosure, you can be off slightly, and not affect too much, as long as you are + - 5%. If you plan to add braces, then you must add the volume of these braces from the original volume to get the new volume requirements. Quote Link to comment Share on other sites More sharing options...
m00n Posted January 5, 2005 Author Share Posted January 5, 2005 As they are now, they are ported 3 ways. Don't see changing drivers or crossovers at this point. Quote Link to comment Share on other sites More sharing options...
michael hurd Posted January 5, 2005 Share Posted January 5, 2005 In that case, you are best off building to the orignal volume, then reusing the original ports, regardless if you change the shape or not, as long as the internal volume is the same. Building a smaller or larger enclosure ( volume wise ) will change the tuning of the enclosure, if the port is not altered in length or diameter. I am building my first ported enclosures, as soon as Canada Post can find my parcel with the flared port kits. Grrr... You might want to confer with some of the others on here, as to how changing one thing upsets the relationship of port to enclosure volume. Quote Link to comment Share on other sites More sharing options...
m00n Posted January 7, 2005 Author Share Posted January 7, 2005 Actually, I had it wrong. The existing cabinets are NOT MDF. It's 1/2 particle board. By going up to a 3/4" MDF, what differences can I expect out of the existing drivers if i keep everything the same? Can I expect an improvement out of them or will it not make a difference? Quote Link to comment Share on other sites More sharing options...
rtaylor Posted January 8, 2005 Share Posted January 8, 2005 Being the expert speaker builder from New Burlington I would assume that the clarity of midrange, highs, and lows would be improved in that order. The bass rumbling around in there and vibrating the panels would put out their own sound while perhaps by vibrating the front panel add even more distortion to the mid and high driver.Take all this with a large grain of salt, preferably sea salt. The suggestion to also brace the panels, especially the larger ones, in my opinion would also help to keep things clear. Good luck, Randy Quote Link to comment Share on other sites More sharing options...
meuge Posted January 8, 2005 Share Posted January 8, 2005 SolidWorks will calculate internal volumes of any shape, no matter how complex. Of course, you'd have to drop a few grand on a license, Quote Link to comment Share on other sites More sharing options...
fini Posted January 9, 2005 Share Posted January 9, 2005 Sanyo?? Quote Link to comment Share on other sites More sharing options...
m00n Posted January 21, 2005 Author Share Posted January 21, 2005 ---------------- On 1/9/2005 9:52:14 AM fini wrote: Sanyo?? ---------------- Yes... Do you have something to say? Hmmm? Seriously. This was my wifes stereo she had before we met. I can't believe how cheaply made these cabs are made. 1/2" particle board? CMon! Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 21, 2005 Share Posted January 21, 2005 Check out this free program: http://www.linearteam.dk/default.aspx?pageid=winisd Don't use the pro version (yet) because they don't have the box modelling features yet. All you'll need to do is use a dummy driver in the program and then figure out the current volume of your cabinet. Enter the box volume into the program and then click on the "box shape" button. Choose a board thickness and then input dimensions you want to work with. After you pick two dimensions, you can then click on the "W, H, or D" and it will autocalculate the last variable. If you want to change the units from mm, to in, to feet then just click on the dimension and it will change (correspondingly changing your dimensions to match the new units). You can also click the optimum button which will give you a suggest cabinet size. Though I have no experience with cabinet building (yet), I would think that the 3/4" MDF would result in a small improvement in sound. Unless you already notice artifacts of the old cabinet vibrating, then you probably won't hear much difference at all. What kind of bracing do your old cabinets have? I would think bracing would make a bigger difference in the sound. Also, don't forget to keep your port openings away from walls inside the cabinet. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 21, 2005 Share Posted January 21, 2005 I forgot to mention...if your old speakers don't already do this, it would be a good thing to isolate the woofer sections from the mids and tweeters...and even the mid from the tweeter. The larger diaphragms move enough air that will make the smaller diaphragms move back and forth. If you do this, don't forget to take into account the volume that the mid and tweeter drivers take up when making the woofer volume (in a ported design, the cabinet volume is important). Quote Link to comment Share on other sites More sharing options...
m00n Posted January 21, 2005 Author Share Posted January 21, 2005 Thanks DrWho for the link. As far as bracing, I don't think there is any. These are some cheaply made boxes. They sound decent, but make crappy. As far as breaking the drivers into sepparate areas? I don't think I'm going to get into that detail. They components just arent worth that effort. Not to mention, I simply don't have the experiance in figuring out all that stuff. And for this set, just making some new boxes, veneering them, having them turn out looking good and sounding at least as good as they do now is about all I'm after Quote Link to comment Share on other sites More sharing options...
dodger Posted January 21, 2005 Share Posted January 21, 2005 Hey mOOn: For the cabinets, two things: Going to 3/4" will give rigidity, thus a cleaner bass response. I use 1x2s glued in place with Liquid Nails to be satisfactory. That may change resonance though. Mounting drivers and ports in the same position will work best. Check the drivers for any foam surrounds on the cone area. They may need it and you may as well get that out of the way now. Good Luck. dodger Quote Link to comment Share on other sites More sharing options...
m00n Posted March 9, 2005 Author Share Posted March 9, 2005 ---------------- On 1/21/2005 9:23:08 PM DrWho wrote: I forgot to mention...if your old speakers don't already do this, it would be a good thing to isolate the woofer sections from the mids and tweeters...and even the mid from the tweeter. The larger diaphragms move enough air that will make the smaller diaphragms move back and forth. If you do this, don't forget to take into account the volume that the mid and tweeter drivers take up when making the woofer volume (in a ported design, the cabinet volume is important). ---------------- Ok... So, I'm thinking about this afterall. I may sepparate the woofer from mid and tweeter. Now, this does create a problem though. They are ported speakers, the port tubing is I'm assuming set to the lenght of the box as it is now. One large box. What are my options? Do I keep with a ported design? If so, how do I determine the length of the port. Or should I just go with a closed cabinet. If I did, what are the sonic differances between a ported design and non ported? Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 9, 2005 Share Posted March 9, 2005 Port tuning deals with the volume of the cabinet. I would use the exact same port diameter and length as your old speaker. To keep the tuning identical, simply increase the volume of the box behind the woofer by the volume you descrease when you seal off the mid and tweeter. A 12x12x6 inch box behind the mid and tweeter is about 864 cubic inches...so if your cabinet is 12" wide and 36" tall, then make your cabinet 2" deeper than it normally is(12x36x2 = 864). Quote Link to comment Share on other sites More sharing options...
m00n Posted March 9, 2005 Author Share Posted March 9, 2005 Ok hold on... You're saying keep the same volume in the woofer cabinet? Just change the dimensions to make it look different? Is that what I'm reading? Just trying to fully understand what you're saying. Just as a design thought, I had pondered making them completely different boxes all together. One box for the woofer, one box for the mid, one for the tweeter, all stacked on top of each other and sepparated by columns if you will.... Something kinda like this. Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 9, 2005 Share Posted March 9, 2005 ---------------- On 3/9/2005 4:18:03 PM m00n wrote: Ok hold on... You're saying keep the same volume in the woofer cabinet? Just change the dimensions to make it look different? Is that what I'm reading? Just trying to fully understand what you're saying. Just as a design thought, I had pondered making them completely different boxes all together. One box for the woofer, one box for the mid, one for the tweeter, all stacked on top of each other and sepparated by columns if you will.... Something kinda like this. ---------------- I think I want to say yes, lol. Just make sure the cabinet surrounding the woofer has the exact same volume as the original design. Changing the actual dimensions of that cabinet will have no effect on the tuning of the port (as long as the volume is the same). A lot of speaker manufactures will create a seperate compartment inside the speaker cabinet that seperates the highs from the lows. I was suggesting that you add such a compartment, and then increase the overall cabinet size to compensate for the change in volume behind the woofer. Physically seperating drivers introduces the comb-filter effect like we discussed this in your HT thread and therefore I would not recommend it. However, this is only an issue if you aren't sitting directly on axis (if you're equidistant from each driver, then the comb-filtering doesn't happen). Another thing to keep in mind is to avoid making the cabinet behind the mid too small, otherwise you might get a nasty boxy sound (and ruin the transition between the mid and the woofer). 800 cubic inches for both the tweeter and the mid should be more than plenty. Quote Link to comment Share on other sites More sharing options...
m00n Posted March 9, 2005 Author Share Posted March 9, 2005 ---------------- On 3/9/2005 7:15:17 PM DrWho wrote: Another thing to keep in mind is to avoid making the cabinet behind the mid too small, otherwise you might get a nasty boxy sound (and ruin the transition between the mid and the woofer). 800 cubic inches for both the tweeter and the mid should be more than plenty. ---------------- Is that 800 cubic inches each or combined in one cabinet? Would it be better to keep the mid and tweeter together in one cab? Also, I was considering trying to keep the width and debth of the mid and tweeter cabinets the same size as the woofer bin, just adjust the height of it/them to adjust cubic inches. Quote Link to comment Share on other sites More sharing options...
STL Posted March 9, 2005 Share Posted March 9, 2005 I'm not trying to be rude, by why bother with the old Sanyos? Do they really sound very good now? I'd watch eBay and buy same beat-up KG4s (or something similar) for cheap and build a new cabinets for them. Then at least you'd have something that sounds good (as well as looks good) when you are done. Quote Link to comment Share on other sites More sharing options...
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