Robbie010 Posted October 13, 2020 Share Posted October 13, 2020 Sorry, I know this subject has been well covered but I can’t seem to turn up these specific details? What is the litre-age that needs to be added with the extra box and are there any other specific perimeters that need to be met? I.e. port length, port diameter? Thanks. Quote Link to comment Share on other sites More sharing options...
Alexander Posted October 13, 2020 Share Posted October 13, 2020 With a LaScala? Maybe I am missing something. Quote Link to comment Share on other sites More sharing options...
Marvel Posted October 13, 2020 Share Posted October 13, 2020 1 hour ago, Robbie010 said: What is the litre-age that needs to be added with the extra box and are there any other specific perimeters that need to be met? I.e. port length, port diameter? A 10 inch hight box will work, 2 ports - 4 inch diameter x 7 inches long. That seems to work the best. If the ports are longer, the bass starts getting a little flabby (for want of a better term). PVC pipe works fine... 2 1 Quote Link to comment Share on other sites More sharing options...
Schu Posted October 13, 2020 Share Posted October 13, 2020 1 hour ago, Robbie010 said: Sorry... What is the VOLUME that needs to be added with the extra box... Quote Link to comment Share on other sites More sharing options...
Robbie010 Posted October 13, 2020 Author Share Posted October 13, 2020 1 minute ago, Schu said: Yes, thats what I meant! Quote Link to comment Share on other sites More sharing options...
moray james Posted October 14, 2020 Share Posted October 14, 2020 Robbie010: Bruce already told you. Make the box ten inches high (internal) and the width and depth to match the LaScala. You should make the vents easy to remove and exchange so you can adjust the vent length (install different length vents) easily to suit what ever room they are in, small adjustments can make a nice difference. 1 Quote Link to comment Share on other sites More sharing options...
Robbie010 Posted October 14, 2020 Author Share Posted October 14, 2020 18 hours ago, moray james said: Robbie010: Bruce already told you. Make the box ten inches high (internal) and the width and depth to match the LaScala. You should make the vents easy to remove and exchange so you can adjust the vent length (install different length vents) easily to suit what ever room they are in, small adjustments can make a nice difference. Thanks, I managed to find the size specifications. I suppose what I’m asking is does it need to be 10” high? Can the same effect be achieved with a shallower box? Raising the whole speaker by 10” seems rather a lot and I was wondering if anyone had modelled the mod using different sizes? From what I have read, the mod can be tuned to a certain extent using different length ports so could a shallower box be used and tuned to gain the same results? Quote Link to comment Share on other sites More sharing options...
moray james Posted October 14, 2020 Share Posted October 14, 2020 25 minutes ago, Robbie010 said: Thanks, I managed to find the size specifications. I suppose what I’m asking is does it need to be 10” high? Can the same effect be achieved with a shallower box? Raising the whole speaker by 10” seems rather a lot and I was wondering if anyone had modelled the mod using different sizes? From what I have read, the mod can be tuned to a certain extent using different length ports so could a shallower box be used and tuned to gain the same results? you can use the volume up top where the mid and hi horn are mounted seal off the back with a plate and mount the vents on that, don't forget that you would need to make an opening into the dog house if you do this. The best height for your cabinet is when the centre of the mid horn is at your seated ear level. With the reflex box on the bottom all you need do is remove the dog house plate/cover and mount the reflex box to the bottom of the cabinet. This makes reversing the modification extremely easy to do. The exact volume is very flexible though you will have to tune the vents if you change volume much. Remember to tune your vents with the speakers set up where they will be playing. 1 Quote Link to comment Share on other sites More sharing options...
DizRotus Posted October 14, 2020 Share Posted October 14, 2020 Here is an example of the way @moray james described above. You avoid raising the speaker 10”. As Bruce described, the ports are 4” diameter by 7” long. 1 1 Quote Link to comment Share on other sites More sharing options...
KROCK Posted October 14, 2020 Share Posted October 14, 2020 Try This; 1 Quote Link to comment Share on other sites More sharing options...
Robbie010 Posted October 14, 2020 Author Share Posted October 14, 2020 Thanks Gents..... I have done some quick maths and worked out the internal volume of my doghouse, plus the internal volume of the additional box. I'll see if I can find an online calculator where I can use these measurements, along with the specs of the K33 driver and work out the sweet spot for cabinet volume / driver response. This is all new to me so I will report back if I find anything of use. Quote Link to comment Share on other sites More sharing options...
OO1 Posted October 14, 2020 Share Posted October 14, 2020 Robbie , not sure you''ll see a difference ---- Quote Link to comment Share on other sites More sharing options...
moray james Posted October 15, 2020 Share Posted October 15, 2020 Robbie010: an on line calculator is not going to tell you how this sounds. The people who have done this mod (which if recall correctly was designed the late DJK) figured this out and did all the testing. Why not scan the archives and ask those who have done the modification and see what thy have to say about it. Dennis also designed a filter box to boost low end response if desired.This mod in room can extend bass by about an octave and that is a BIG deal. Quote Link to comment Share on other sites More sharing options...
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