Balcro

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.

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".

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.

PM to OP.

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

Some specimen FANE Sovereign graphs for frequency response & power handling. The Faital Pro is similar.

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.

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.

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.

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.

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.

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.

THanks for that. Balcro

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.

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.

Thanks Bill, It looks as if I am in the right area with 18 M/S in the pass band. Balcro

When modelling speaker drive units in winISD I understand that to avoid Port Chuffing you should keep Air Velocity below approx 18 M/s. Mostly, higher Air Velocities occur down at 22 - 35Hz or so, while the level @ 100Hz usually stays at about 3 - 5 M/s When modelling, I would set the input power level to either full rated power throughout the response range (for those units that can achieve it) or at the bottom of the traditional power-handling "60Hz dip" so that "xmax" is not exceeded. What would be good / best practice? Any comments, technical or otherwise. Balcro.

AUDACITY - If you haven't already done so, you need to install the "lame" encoder for Audacity. Go here :- https://manual.audacityteam.org/man/installing_and_updating_audacity_on_windows.html#winlame Once up & running, Import the FLAC file --> Select "Export as MP3". When "Save" dialog box appears with "Format Options", select "Insane" or "Extreme" quality. Other options:- Ashampoo (ashampo.de English) - Music Studio 2018 - the free version should do it. Alternatively, Music Studio 6 or 7 - short term trial versions.

Hello Douglas, Having put your supplied figures through winISD I would say you have a workable solution. The finished speaker will be more than loud enough for home practice or even a jam in the garage with a mate. That level of loudness will be achieved by only putting in 50 watts! So your amp will be cruising nicely. If you can get one round plastic pipe of about 3" internal diameter and 2.8" long, that will do for the port. Alternatively, two 2" ports of 2.5" internal diameter will work with a length of 5.1". In both cases the tuning is at 59Hz. If you can confirm the port sizes you have to use, (your pipes in the USA may be different to ours) then I can tell you the required length.

As Bill said, there are many considerations involved. First of all, think about closing up the back panel. Download and install the latest version of winISD - see Bill's link. Then post the information you have on your chosen 12" bass unit. Once the model and/or it's details (Theile/Small parameters) are visible, then a number of people on here can let you know whether it's suitable for bass and suitable to fit in a 30litre enclosure.

Hi LukeFRC, I can confirm chienmortbb's (Tuesday post) earlier estimate of "how loud it will go". Just ran winISD in auto mode - it sets the volume @ 69.81 litres. The following are basic & theoretical figures without fine tuning, nor is there reference to the actual volume of stevie's cab:- 165w input gives a maximum SPL of 119dB from 80Hz upwards!! xMax is only exceed below 37Hz at which point the output is 108.5dB. There's no arguing with stevie's assertion that "this cab will certainly go as loud with your amp as any other 12" cabinet out there." No discernible difference in output between 165w & 300w - the graph lines overlay each other. Putting 2 drivers in - just for fun- & upping the volume to 130 litres (still with 165watts) gives a potential 124.7db!! Balcro.

Mike Shrieve giving it his all on the biggest stage. One of rocks' magic moments and my favourite Woodstock clip. New Santana CD's sitting 4' away ready for Christmas wrapping.

Hi paulbuzz, I've re-done the responses with the 3 drivers, on the basis of a 17.2 litre enclosure with the port length unchanged at 12.5cm. This gives you clearest comparison. If you alter the port length it means cutting wood and damaging the enclosure. There are many variables involved because none of the drivers are an immediate best fit. To work with the port length, some of the drivers will need to have adjustments to the port area. In all three cases, at 100watt input, things don't look too bad, but change the input to 200watt and things start to get out of control. Frequency response around 100-150Hz pushes the response curves into exaggerated peaks, the port ventilation requirements increase to a point where "chuffing" might occur and the requirement for the vent area can exceed the available size. Of the 3, the Eminence is the least adaptable. Push up the ventilation to reduce port noise and the power handling suffers. It's not a bad drive-unit, I just think it's the least suited to this enclosure at 200w input. Of the other two, the 18sound is marginally better than the Celestion: 50 watts more power-handling down to lower frequencies (54Hz compared to 72Hz for the Celestion). The response curves around 125Hz are similar. In practice (and for both drive-units) I would think the latter difference could easily be eq'd out by cutting the bass a touch. If there's a "middle" control, boost that a little. If more reserve is your requirement, then it's the 18sound. At 200watts both drive-units are pushing the likelihood of "port-chuffing" but you'll be so loud you probably won't hear it - see last para. No 100% solution with either the Celstion or the 18sound. Looking at winISD, you have to assume it gives you the complete picture, and there's an ideal bass response which you'll like, but what's the original like?! It could be far inferior in terms of even frequency response or how it presents in winISD, but might still sound very impressive. Putting in one neo-dym speaker will probably only save you 1Kg. Without a full specification on the original no one can say the replacements will be sound better or louder (winISD @ 200watt input is predicting a sound pressure level of around 116dBa for the 18sound ) (you want to get louder?) and as Bill Fitzmaurice has said, you won't get extended bass in that small box.

Hi paulbuzz, I'm working on it. Comparison pictures up later - we've got plumbers in at the moment - Original assessments from last year and the new 18sound driver have had to be adjusted for maintaining the port length of 12.5cm. The 18sound is looking very good. More later.

Hello Geoff, Do you have a problem? Balcro.