B.Flat Posted September 20, 2011 Share Posted September 20, 2011 Hi, I wonder if anybody can throw a little light on the following query? I have, as part of my rig, a 2 X 10" cabinet, designed with the WinISD programme. It is actually two 1 X 10"s as the enclosure is divided into two, 33 litres each side. I have ported each of the two sections with a 40mm dia. Port, 19mm long. These two ports can be sealed, giving the option of closed or vented. The drivers are two Eminence Basslite 2010’s, 150 watts each. The cab works well to my ears. However, for reasons, which need not be detailed, I wish to replace the 2010’s with a pair of Deltalite 2510’s. 250 watts. Looking at the Eminence spec. sheet the recommended cab volume is a maximum of 17 litres and 39.6 litres closed & vented respectively. As an experiment I have reduced the volume of one side, with the aid of polystyrene blocks, to 23 litres, and left the other side at 33 litres. As each driver is on a separate connector I have been able to listen to the various options now available. That is:- 23 litres vented ( port 40mm dia. X 19 mm) or closed. The result is fairly tight mids with good highs, but not too bright, and a rolled off bass response with the port closed, better bass and more volume (apparently) port open. With the 33 litre side roughly the same but deeper bass response and more apparent volume. So, if you have had enough interest to read this far, my query is this. I am driving these speakers fairly hard, sometimes up to their max. I know that the ports are nowhere near the WinISD calculations, but to my aged ears the cabinet does not sound bad. It is supported by two subs, so bass response is not critical. However, am I putting the speakers at risk with either, a) too-large a box volume as in the 33 litre closed version, or with the wrong port dimensions in both cases? Anybody who can help will be eternally blessed by me, as my elderly brain cannot get round some of the performance graphs on the WinISD programme !!!!! Thanks for reading, B.Flat Quote Link to comment Share on other sites More sharing options...
Moos3h Posted September 20, 2011 Share Posted September 20, 2011 Let your ears tell you what's going on. All of this stuff is important in terms of getting a speaker to behave how it should, but actually that still may not yield the sound you want. If you can't hear any distortion or bottoming out then it's my uneducated opinion that the speakers will be just fine, there's a chance that their expected lifespan could be reduced, in theory - but again if your ears say it's okay, it's okay! Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted September 20, 2011 Share Posted September 20, 2011 The WinISD side of things only covers <200hz, so if you have subs supporting, might not be super relevant and you are best off high passing the boxes so excursion ceases to be an issue, and you won't be countering the subs output by having multiple sources of lows. Low port tuning (long port) or sealed box also rolls off the lows achieving similar. Quote Link to comment Share on other sites More sharing options...
B.Flat Posted September 20, 2011 Author Share Posted September 20, 2011 Thank you for the speedy response to my query, you guys. Excellent ! If I could trouble you one more time, would you give the same answer if the cabinet was not hi-passed, and received the same signal as the subs? I have not tried this but I can forsee a situation where I may want to./ Thanks again B.Flat Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted September 21, 2011 Share Posted September 21, 2011 Interesting question. We don't know from your post how the subs crossover to the 10's. If the bass to the 10's is filtered you have no problems. Your cabs are tuned to a particular frequency, by changing speakers they may not match the new speakers. Filling the volume with blocks will raise the tuning frequency of the cab. Having a tuning frequency which does not match your speakers will affect the frequency response low down and if it is particularly bad might cause you to suffer over excursion of the speaker cones at lower powers than if it were tuned properly. You'd hear this as a farty rattly distortion that wasn't there before and it would be a warning to turn down. If you are not noticing it you probably don't have a problem though you are carrying around a cabinet which might not be getting the best out of your new speakers and which could be smaller. When you get time you can feed the new speaker specs and the box size into winISD and see what size the ports should be and try these out. you obviously don't mind a little fiddling. Quote Link to comment Share on other sites More sharing options...
B.Flat Posted September 21, 2011 Author Share Posted September 21, 2011 Hi Phil, thanks for that. Actually I do mind a little fiddling ! I am now in my late 60's and don't have the pazazz ( or workshop facilites) that I once had. The reason for this query is that I have gone the neodymium/digital route because I don't have the strength or motivation to haull heavy gear any more. So, I have a choice of three digital/programmable amps and four neo cabs to cater from 250watts up to 1400watts. The most powerful amp is a CROWN XTi which, thanks to the internal DSP, I can insert filters so no problem. The other two amps I can use in tandem and programme one for Hi end & the other for low end, so again no prob. The problem, if there be one, arises in the middle amp, 1000 watts (2 x 500 watts), which is the amp of choice for medium size rooms, where I have to use the two 1 X 10" subs and the 2 x 10" ( all Deltalite 11 2510's) but with no filtering or xover facilities. I am hoping that by closing the ports or reducing the internal volume of the 2 X 10" I will take the drivers out of harms way. Having said that I do like the sound of the 33 litre open port option. I have absorbed all the forgoing advice and it seems the "trust your ears" is the way to initially see which way the wind is blowing. WinISD says the box tuning of 33litres with the 4Omm X 19mm port is 51.14 hz. Is there any indicator in the WinISD programme which will tell me how this should handle 250 watts, if that is an intelligent question? Again I take the point that my ears should tell me if anything is going seriously wrong, but I do like to "muck about" on WinISD to try to improve my limited knowledge. Again, all replies very gratefully received. B.Flat Quote Link to comment Share on other sites More sharing options...
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