jwc Posted April 4, 2006 Author Share Posted April 4, 2006 By all means, I bet it is too low. I think the port length should be about 5". I'm not sure I understand your example of using the speaker as a microphone. Be more specific. I have done what Al suggested measuring a port and the driver independently upclose. That left side of the curve is different. There is no peaking a 35Hz then a dive again at 40-50Hz and then peak again at 60Hz. I'm not taking the speaker outside. However, I may think of how I can do that tilt thing.T Tell me more about hooking the speaker in "parallel" Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 4, 2006 Share Posted April 4, 2006 jwc, He's talking about running a line back from the speaker terminals, into a LINE input on your sound card, and measuring the response. the loading a response of the speaker system will affect the response you can display. It can't be a mic. inout as the signal level will be too high. A line level should indeed provide very little current flow into the sound card and not damage it. Plus, you shouldn't have to play back at a very high level at all. It works the same way that putting a DMM across something. The meter input is a very high impedance so the circuit pretty much doesn't see the meter. Bruce Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted April 4, 2006 Share Posted April 4, 2006 jc, I have the formula for combinging the two plots witn a single port, but I will have to do some research when a dual port is involved. Post the plots anyhow. They will tell a lot of other good things anyhow! Al K. Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 The woofer upclose with ESN, dual 4" ports 10" length Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 The one port upclose with ESN, dual 4" ports 10" length Quote Link to comment Share on other sites More sharing options...
BS Button Posted April 4, 2006 Share Posted April 4, 2006 Crap, you're pullin away. I'm in your dust. Remember that movie. "I'm gonna getcha sucka" Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 Ok here. same test with 7" ports Here is one port only Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 here is the woofer only with 7" ports Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 Ok guys. Here is the RTA of the Bass Bin currently with the 7" ports from the listening position. Looking better. Ran 7 times and this is the average. Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 Now we are talkin. Look at all the drivers with the bass bin with 7" ports Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 I've been listening to them for about 45 minutes. Placed them next to the dbb's. You can see now that they don't look as tall as you may have thought. The dbb's are the height of a Khorn. The TallCorns will sit in a position just like this at the lakehouse. They are just over one foot from the back wall. It is noticeable that these cabinets are tuned lower. I am embarrased to say that I have heard sounds I haven't heard before on some of my standard test music. I'm not sure if it is a result of Bob's Tweeter or that ESN. The Tallcorn is balanced. I'm sure it will have a little less crispness when I put the Grills on there. They sound great. It may be time to paint which I dread. I must say that the RTA on this project was a big help. Whether or not the speakers are balanced in general or just balanced to my room...not sure. I hope I didn't bore too much with the graphs. I still can change the ports at anytime if someone wants to contimue with the suggestions. I am yet again impressed. My initial opinion is that these are sounding better than my Cornscalas but not the dbb's. The TallCorns do go lower with the bass. They again can go VERY loud and be tolerable at the same time. jc Quote Link to comment Share on other sites More sharing options...
BEC Posted April 4, 2006 Share Posted April 4, 2006 jc, When are you going to start the Cullison Speaker Company? Looks like you are getting the speaker line-up covered pretty good. Bob Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 4, 2006 Share Posted April 4, 2006 Very nice looking. Are you going to have these painted (thought you had mentioned that) or do some sort of stain on them? Bruce Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 Funny you mentioned the stain idea. I just now had asked my wife about veneer or stain am I got a firm "Hell No". They will be jet Black painted. Grills Duracrest #17 Black. Yes the Cullison Speaker Company. Grand idea. It is already in business. I sell products to myself. I wish I could make a livin doing this. jc Quote Link to comment Share on other sites More sharing options...
jwc Posted April 4, 2006 Author Share Posted April 4, 2006 Bob. Do you remember from my past dbb thread in which you were sending me links to test audio sound files in order to "see" the excursion of the K33 in my dbb's? You know, to this date, I have never seen them move. I mean really, the room is full of great bass and you can put your eyes up to them and they aren't moving. Now with this new woofer of yours, that isn't the case. Yes the woofer is "moving" when turned up to a high volume (too high for my casual listening). What do you think about this. Is the due to the high efficiency of the dbb's (probably slightly more than the Khorns) or just the fact I've got two woofers on the dbb's requiring "less work"? jc Quote Link to comment Share on other sites More sharing options...
BEC Posted April 4, 2006 Share Posted April 4, 2006 I would say you are working the single woofer harder. Also I think the CW1526 may move more at the lower frequencies since it can reproduce more of them. Bob Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 5, 2006 Share Posted April 5, 2006 And because the CT digs lower it probably has a steeper Q on the cutoff...which means the woofer is unloading faster. You might consider going back to the 10" ports and throwing in a peaking-2nd-order highpass filter...it'll only increase cone excursion in the range of the tuning point (where the cone is barely moving at all) and then it will protect the driver from signals below the tuning point. You can model it in winISD to get an idea of what I'm talking about. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted April 5, 2006 Share Posted April 5, 2006 Jc, What procedure did you use to tune the port? I see plots for different length ports. You need to actually tune the port correctly before you bother doing any plots. AL K. Quote Link to comment Share on other sites More sharing options...
jwc Posted April 5, 2006 Author Share Posted April 5, 2006 Al, my decision on ports lengths were all estimated first in WinISD. I was shooting for a cabinet tuned to about 39Hz. When plotting this with BOB's woofer in a 6.5 cu ft cabinet, the dual 4 inch port lengths would be about 4-6 inches. Now I started out longer just for the heck of it. The 10" plot was looking like some estimated on WinISD when the length was too long....in other words....starting to roll off slowly under 80-90Hz. The plot would never roll off quickly on the low end and just continue on onto the very low frequencies. The Cornwall basically will peak bigtime between 50-80Hz and drop off fast. Other than that, I have done the above posts. I would appreciate further help to perfect the tuning. So maybe I am not doing the basic work to "tune the ports". Tell me how. Doc Who. You think the low frequecies will be harmfull to my woofer. Not sure how that peak bandpass will integrate with Al's design. I would rather have the woofer just roll off very quickly on the low end. I still think the port could be shortened a little bit. I must say that it sounded pretty good the way it is right now at 7". Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 5, 2006 Share Posted April 5, 2006 Doc Who. You think the low frequecies will be harmfull to my woofer. Not sure how that peak bandpass will integrate with Al's design. I would rather have the woofer just roll off very quickly on the low end. I still think the port could be shortened a little bit. I must say that it sounded pretty good the way it is right now at 7". The filter would have to be an active one...as in go before the amplifier - so it wouldn't affect Al's passive network. I do not think you will damage the woofer at all - just that any cone movement = distortion. But if it sounds good then hands off! Shut up and enjoy the music [] Now if you want to play around with it I'm all for experimentation. You should have quite a few different lengths of port by now shouldn't you? Just for kicks you should try porting too high (like use a 4" length leftover). One thing you really need to be doing is testing the system at different SPL's (which is another reason outdoor testing is a good thing...). We've talked about the cornwall being ported too high in the past and though that might be true for the "low-signal behavior", I bet the higher port tuning becomes beneficial with the "large-signal behavior" - all that to say, try measuring at ear bleed volumes, just to get an idea of what direction the system starts to lean. Btw, try doing some of your measurements, but with the mic on the floor...there shouldn't be much directivity at those lower frequencies so don't worry about tilting the speaker forward. I'm thinking it might get rid of some of those steep dips in the response. Quote Link to comment Share on other sites More sharing options...
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