Hifisound Posted December 17, 2013 Author Report Share Posted December 17, 2013 Just found this interesting driver and an associated DIY project during some searches http://www.mccauleysound.com/accessory_overview.cfm?ID=126 http://techtalk.parts-express.com/showthread.php?230388-Linear-phase-18-quot-McCauley-6174-subwoofer http://www.bodziosoftware.com.au/ Just thought of mentioning it here.... Link to comment Share on other sites More sharing options...
Hifisound Posted December 20, 2013 Author Report Share Posted December 20, 2013 Will Crown XLS1500 be able to power more than 2 subs with either Dayton RS HF 15" or ultimax 15" ? Link to comment Share on other sites More sharing options...
Ricci Posted December 20, 2013 Report Share Posted December 20, 2013 The McCauley 6174 driver has been around for many years. IMO it has been surpassed by newer driver designs for less money. An XLS1500 could power 4 drivers or even 8. You may not push the drivers near their maximum potential but it is plenty to make a good amount of noise. You do not always have to over-amp the drivers like most do. Link to comment Share on other sites More sharing options...
Hifisound Posted December 22, 2013 Author Report Share Posted December 22, 2013 Any impact enclosure shape on THD levels ? The very old winisd gives dimensions 21" W x 34.2" H x 12.83" D for a QTC 0.71 153.7 L box for Dayton 15" RSHF. Most sealed DIY projects I see are cubes or very close to that (The data-bass enclosure for Dayton 18" RS HO is 22" cube) Is there a "best" sealed enclosure shape ? Also regarding exact cube shape : Its typically recommended that room dimensions should not be same or in multiples of each other (if I remember right), doesn't same apply to sub enclosure ? or it doesn't matter at typical enclosure size we are dealing with, unlike the room... Link to comment Share on other sites More sharing options...
Ricci Posted December 23, 2013 Report Share Posted December 23, 2013 There really isn't a best enclosure shape at least as far as bass is concerned. The only real concern with the shape of subwoofers is if the internal enclosure dimensions become large enough to cause resonances below 200Hz and that larger panels become harder to adequately brace against vibration. resonances down in the bass range need dimensions that are quite large and correspond to 1/4 wavelength. The speed of sound is roughly 1130 feet per second at sea level. 1/4 wave resonance at about 150Hz requires a dimension of 22.5". The larger the surface area of parallel panels with the same distance from each other the stronger the energy will be. However there are ways to combat this with internal damping material, strategic placement of bracing and even the driver motor can help to break things up. Again this stuff is far more critical in woofers and mid woofers where the cabinet resonances are much more likely to fall directly into the functional passband of the system. For a 22" cube with 1" thick walls you would have an internal dimension of roughly 20" corresponding to the lowest frequency resonance issue appearing at about 170Hz which is about an octave above the typical subwoofer crossover and with some damping material can likely be quashed effectively to begin with. Link to comment Share on other sites More sharing options...
Hifisound Posted December 26, 2013 Author Report Share Posted December 26, 2013 I modeled both Dayton RSHF and Ultimax 15" in WinISD and it showed similar results for both. Guess I can stick to HF 15" I used a volume of 131 L which would be 20" inch inner cube and hence 22" cube overall Is this is fine or shall I go for lower volume ? Also at 131L will polyfill be required ? Thanks.. Link to comment Share on other sites More sharing options...
Hifisound Posted January 1, 2014 Author Report Share Posted January 1, 2014 Any thoughts on the enclosure size ? Link to comment Share on other sites More sharing options...
maxmercy Posted January 1, 2014 Report Share Posted January 1, 2014 3-4 cu ft is good for the RSHF. I have never modeled the UMax. JSS Link to comment Share on other sites More sharing options...
Bossobass Dave Posted January 3, 2014 Report Share Posted January 3, 2014 There really isn't a best enclosure shape at least as far as bass is concerned. The only real concern with the shape of subwoofers is if the internal enclosure dimensions become large enough to cause resonances below 200Hz and that larger panels become harder to adequately brace against vibration. resonances down in the bass range need dimensions that are quite large and correspond to 1/4 wavelength. The speed of sound is roughly 1130 feet per second at sea level. 1/4 wave resonance at about 150Hz requires a dimension of 22.5". The larger the surface area of parallel panels with the same distance from each other the stronger the energy will be. However there are ways to combat this with internal damping material, strategic placement of bracing and even the driver motor can help to break things up. Again this stuff is far more critical in woofers and mid woofers where the cabinet resonances are much more likely to fall directly into the functional passband of the system. For a 22" cube with 1" thick walls you would have an internal dimension of roughly 20" corresponding to the lowest frequency resonance issue appearing at about 170Hz which is about an octave above the typical subwoofer crossover and with some damping material can likely be quashed effectively to begin with. Higher frequency resonances can be triggered by lower frequency pressure waves. Bracing is touted as the method to offset the down side of large panels, but they add weight, add complexity to the build and are many times done to no avail because they are anything but engineered. The shape of the box can eliminate large panels and the need for complex, weight-adding and time-consuming bracing, and accomplish the end goal; to eliminate panel resonances. BassBox Pro has a very extensive enclosure shape library that quickly calcs internal volume for the math-challenged and lazy, and might provide a box shape idea that you haven't thought of before. If you're not the inventive type, the cylinder is a great choice. It has only 3 sides and the main 'side' requires no construction engineering. Just avoid cheesy ones like Sonotube. If you can't find a thicker-walled cylinder, cut a couple of halos that will slide snugly into the interior over some PU adhesive. IMO, the cube is the worst choice for the reasons stated and… it's boring… evolve already Link to comment Share on other sites More sharing options...
Hifisound Posted January 4, 2014 Author Report Share Posted January 4, 2014 I was comparing the optimum sealed volume and sealed F3 for Dayton 15" HF and ultimax 12" 15" 18" https://www.parts-ex...-4-ohm--295-468 https://www.parts-ex...r-coil--295-512 https://www.parts-ex...r-coil--295-514 https://www.parts-ex...r-coil--295-518 Isn't F3 of 34Hz in 2.8 cuft for 12" ultimax a surprisingly good number ? and there is just 1 Hz improvement for 15" and 18" ulitmax. HF15" has an higher F3 than 12" ultimax ! Is this data plausible ? Link to comment Share on other sites More sharing options...
Hifisound Posted January 4, 2014 Author Report Share Posted January 4, 2014 Also since Bossobass Dave mentioned about various enclosure shapes, I thought I will share a very radical idea I got (could be a silly one too ) Its also with nearfield sub setup in mind (got to read about it here http://mehlau.net/audio/dual_nearfield_sub/ and seems quite useful ) Between 1-2 ft distance between me and driver. The idea is to build a mdf based study table such that it has a sealed subwoofer between its two drawers or instead of drawers/cupboards it has 2 sealed subs Rough front views attached I know that it takes away the flexibility of placing subs in best place in the room. But if nearfield works as mentioned and there is minimal room impact this would be great! What do you all think ? Link to comment Share on other sites More sharing options...
Hifisound Posted February 21, 2014 Author Report Share Posted February 21, 2014 Has anybody tried Acoustic Elegance SBP15 driver ? Has Fs : 21.3 Hz and extremely low Le: 0.3 mH Link to comment Share on other sites More sharing options...
Hifisound Posted April 6, 2015 Author Report Share Posted April 6, 2015 Reusing my old thread Slight alteration in plans Will want to go for even smaller subs so that some small monitors can be kept on top of them with crossover around 250Hz. Would prefer to go for a cabinet like this http://www.parts-express.com/denovo-audio-knock-down-mdf-067-cu-ft-subwoofer-speaker-cabinet--300-7068 Found the following 2 drivers which give F3 of 40Hz (as per winisd) http://www.parts-express.com/dayton-audio-rss265ho-44-10-reference-ho-dvc-subwoofer--295-463 http://www.parts-express.com/dayton-audio-um10-22-10-ultimax-dvc-subwoofer-2-ohms-per-coil--295-510 but for qtc of 0.707 they require 0.84 cu ft and 0.91 cu ft respectively . Will it be an issue to use them in 0.67 cu ft cab ? Thanks... Link to comment Share on other sites More sharing options...
MemX Posted April 6, 2015 Report Share Posted April 6, 2015 AIUI, if you stuff the boxes it will change the response curve downwards, so a higher QTC box will have a lower QTC response curve, but it won't allow any increase in output that a bigger box may provide. I think... Link to comment Share on other sites More sharing options...
Hifisound Posted April 6, 2015 Author Report Share Posted April 6, 2015 AIUI, if you stuff the boxes it will change the response curve downwards, so a higher QTC box will have a lower QTC response curve, but it won't allow any increase in output that a bigger box may provide. I think... Output shouldn't be an issue for nearfield, esp with two of these.. As long that cabinet with stuffing works , it should be fine ... Any suggestion between the 2 drivers ? The RSS265 looks pretty flat till 500Hz but has nasty breakup Link to comment Share on other sites More sharing options...
MemX Posted April 6, 2015 Report Share Posted April 6, 2015 I have to admit I have zero experience / knowledge / opinion on those drivers! I always hate referring fellow forumites 'off-forum', especially one as good as this one, but I think it could be worth having a search on DIYAudio forums - they seem to have a fairly large membership that, between them, have considered / opined on / actually built with most of the drivers out there, it seems! lol Link to comment Share on other sites More sharing options...
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