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About Balcro

  • Birthday 08/12/1947

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  1. Your starter for 10. It's not that difficult. If you can calculate the internal volume of a speaker cabinet (HxWxD) you're part of the way there. It's mainly of use if your choosing or replacing a speaker drive unit in a existing cabinet or if you're building your own loudspeaker from scratch. Download the latest version 0.7.950 directly from here : - linearteam.org Install and start the program. The program needs you to enter the Thiele / Small Parameters which you can find on nearly every manufacturers web-site. For example: https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=101060100 These go into a "Parameters" dialog box / panel on the program and are saved into a database of "drivers" You start by creating a "NEW" (White Icon) project - select / highlight the Manufacturer or Brand, double click to reveal individual drivers. Select ADD NEW. The driver for which you entered the data e.g as above. When the dialog box appears click on the "Parameters" Tab. Enter the values for Qes, Qms VAS, Mms, Cms, Re, Le, Xmax, Pe(rated power in watts) and Znom (Impedance - usually 4 or 8 Ohms) into their respective boxes. winISD auto-calculates the other details. Be careful to select the right units at the side of the data boxes - click if necessary on the tiny script. Click SAVE & give the data a name. You don't need to understand the meaning of the parameters, you can find that elsewhere if you interested in an academic exercise. Return to "Create New Project" and find the named file that you've just saved. You should see a green bar with the words "integrity checks OK". Click LOAD. A file manager appears from where you select the driver you want. Click "Open". Thereafter it's a couple of clicks - 1. Standard placement, 2. Vented or not, 3. Alignment - nearly always QB3 4. Give the project a name 5. Click "create" and winISD produces a graph. If you click on BOX, it shows you a chosen volume. You can adjust this. If you click on Vents, it shows you the diameter of the ports for a given tuning. Again, this is adjustable. At the top of the screen there's a sort of Tab called Transfer Function Magnitude; click on that and you get a drop down menu with a number of useful options most of which are easy to understand like Maximum Power. At the bottom left of the screen click on "Signal" and enter the rated RMS or SAE (not program or music-power) power into the box marked as System Input Power (Watts). Then go back and try the options again. Select the Driver, Box or Signal, make your changes & check the graphs again to view the changes. After that, it's practice.
  2. Hello Sharkfinger, In reply to your first question, the size of the round port, the answer I get is no. I set the box volume to 86L and tuning to 46.24. The result for me was a round port of 13cm diameter and a length of 12.08cm. I'm not sure about the mix of T/S parameters and how they might mix things up, but worthwhile having a double check on them. The one that gets me is usually Cms. I get the millimeters & micrometers mixed up. How much that has a bearing on your overall results and the dreaded "driver fails integrity check" I couldn't say. When I tried the assessment for a square / slot port using your dimensions of 45cm x 8.3cm, I ended up with winISD quoting a length of 44.81cm. Obviously too long, but there was a lot scope to reduce the length without a bad efffect on the "rear port air velocity".
  3. At £350 you're definitely into refurbished PC laptop terrritory. I saw this at Currys. https://www.currys.co.uk/gbuk/computing/laptops/laptops/hp-pavilion-15-bc550na-15-6-intel-core-i5-gtx-1050-gaming-laptop-512-gb-ssd-10193844-pdt.html For video editing this is probably you're starting point. I suspect the code number (bc550na) is mixed up because I can't find good info about it after searches or at HP themselves, so it's probably an old model or a Curry's special. Memory can probably be expanded to 16gB which would be better. worth checking. Don't assume Core i5 is slower than Core i7. It isn't always; there are lots of overlaps in CPU performance.
  4. Hello Bill, You and I obviously have different philosophies when it comes to using winISD. I start from a point where there is a fairly even balance from approx 80 - 250Hz then let the other details fall into place. In this case, graphs are "specimen graphs" the SPL is listed in the text (Post from 3hrs ago) (for 140 watt input). Putting the input up to 220Watts (eg. for the FANE) only achieves another 2 dB and yes, the rear port air velocity is still OK within the passband. The second graph is there just to illustrate the point about the dip in power handling for the benefit of the OP. Balcro
  5. Some specimen FANE Sovereign graphs for frequency response & power handling. The Faital Pro is similar.
  6. I've tested a number of 15 inch bass drivers suitable to work in a cabinet that has a volume of about 108 litres. The best fit is the FANE Sovereign Pro 15 600LF. 220 watts all the way down to 32Hz. At that level of input it's blasting out 120dB!! https://www.fane-international.com/view-product/SOVEREIGN-15-600LF#tab-1 Close to that is a FAITAL-PRO 15 PR400. A neodymium magnet speaker. A full 185w down to 33Hz. At that input level it's putting out just under 119dB!! https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=101060100 The CELESTION PULSE 15 works similarly but has a lot less power handling @ 119watts down to 33Hz. Even at this input level, the sound output is about 117dB! https://celestion.com/product/158/pulse15/ I don't know if you're going to like this, but all of these are around £140-00 and all have a different (but classic) power handling dip (from their nominal rating) between 45-100Hz. These result are somewhat academic as the sound levels produced are huge, as is the headroom these units provide. If anyone else has alternative drivers that are cheaper, please feel free to add.
  7. Hi DanDare, Agreed, yes. I understand your comment, but in this case and at this stage all you need are the externals from which you deduct 18mm per panel with a small extra allowance for the front baffle recess. It's simpler for the OP rather than breaking out the screwdrivers etc. As winISD auto-calculates port length from a given port diameter, the existing port will have to be accepted as part of the calculations. I don't expect the final advice will give a 100% solution, but it could be 95% plus. PM to bigevilman.
  8. Good morning Joe, As it sounds like a total loss, you'll need to give the forum some measurements:- the cabinet external height, width & depth. Then measure the diameter of the port at the back. Do that and then get back to us here. From that we can give you the best advice.
  9. To echo Phil Starr, the FANE Sovereign Pro 8-225 is the best fit I've seen for a cabinet of about 18 litres net volume. It models in winISD very well. It's not 100% but I'd say it's 95%. Bear in mind the impedance change from 4 to 8 mentioned above, but otherwise it's definitely a get-out-of-jail choice. A quick search showed Blue Aran selling it for 2 different prices - one at £46.84 and the other at £56.88, depending upon the day in question. Fitting in your speaker cab depends on the frame shape, the overall diameter and the diameter of the fixing holes. Some older models appear to have shaved sides to the frame. See here for dimensions. https://www.fane-international.com/downloads/FANE-SOVEREIGN-8225-DS141117.pdf By the way, if you look at the data sheet - see the General Specifcation section which shows how "power handling" can be inflated! Your unknown original speaker is in fact only rated at 175w - it depends which website you're looking at.
  10. No .1 Do as Phil Starr says. Just because it says 300W on the speaker does not mean the speakers will handle 300 W down to zero. Many a speaker will have a power capacity that dips in the 50-70Hz range; it depends upon the overall speaker design and the drive units. The Vanderkleys may well have no dip - no one can be sure. There may be a minor fault somewhere on the amp or the speakers. If the illustration on Gear for Music is accurate than you have the facility to radicaly reset the eq. Turn off the "Bass boost" switch and cut the bass down to -15. 2. Leave the Low-Mid Bass Range set on 165. Re-start & test, with the emphasis on getting the low-mid settings right - slowly increase the level. 3. Likewise with the High-mids. Set the range anywhere between 600 & 1K; re-start, test & adjust. 4. Presumably the "Enhance" switch works in the middle-upper range. Check the manual. Start with it off and slowly increase but without causing the clip light to function. 5. Slowly bring the Bass level back up, but not too much. Minus 12, minus 9; Try it & see the result. Good luck.
  11. Ah! The Acoustical Resistance Unit. I seem to remember this being linked to a Goodmans catalogue. The idea being that it gave a smoother low-bass roll-off than a ported enclosure with a touch more extension. The odd hi-fi brand also made use of the idea. Celef Audio was one. Specific size was not as precise as a port for tuning. If you had an 18" speaker then you probably needed a 10"x10" ARU; smaller hi-fi style speakers only needed a 6"x 6" or even smaller. You can still get them today - SEAS the Norwegian hi-fi loudspeaker manufacturer offer a small round version.
  12. Another question for Bill. Can you expand upon your meaning of passband. I've looked up the meaning of "passband" but it can be a very wide or very narrow range. In respect of a single bass driver, when you said "within the passband at full excursion" do you mean from the low point where xmax is reached up to the top of the range or is there some other range of frequency response. Thanks. Balcro.
  13. THanks Phil, I take your point about the problem with multiple ports. There's probably some deep turbulence / friction physics going on there, because the addition of more ports seems to be increasingly non-linear where resultant port length is concerned. I've just tried adding some filters to a specimen frequency response and the difference can be dramatic. Air Velocity was reduced from 20 down to 13.2 @ 40 Hz and the reduced Cone Excursion below 35Hz was even better. A definite alternative solution for chuffing, particularly in small boxes. Two bonuses for the price of one. Balcro.
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