Balcro

A simple explanation from 20 hours ago? --------- "In 1979 I went with a friend to The Nashville Rooms in West Kensington to score some dope. William & I were hanging around the main bar, which was rapidly filling up with a bizarre assortments of mods, rockers, punks and new romantics ... these were people you never saw in one place unless something was kicking off between them. Will had the self-preservation instincts of a lemming and flagged down a passing skinhead to ask what was going on. "It's a great new band called Madness" he shouted. Will and I looked at each other, said "nope, me neither", and we went off to find our dealer." H J.

I hope I'm as involved as guys from that generation. Once a week I volunteer to teach general computing / internet etc., to old folks. There's one guy there, 94 & very deaf, who last year was trying Audacity and has now switched to learning Excel despite macular degeneration.

Your task in evaluating what's needed vis a vis 10 or 12, (reference to BFM's post on Wednesday 19.20) is made all the more difficult by the really poor "specifications" listed on theTrickfish web-site. The TF112 is quoted as handling 300w peak. Does that mean it's only 150w RMS or even as low as 75w RMS!! Confusing frequency response shown as 35Hz - 16K listed alongside mention of a 12" neo custom speaker from Eminence; that range is for a combined 12" bass & compression driver. Plus or minus how much? It doesn't say. Probably + or -12 or greater and the compression driver is quoted as extending to 20K!! There's no statement of general efficiency so you have no clue as to how loud it will go! There are some good things built-in such as Peak Protection, HF attenuation, and a sophisticated EQ, but overall the specification hides more than it reveals. A specification written by the marketing side of the business. The half size 0.5 Bullhead amp is differently described as having "continuous power" while your 1K Bullhead has "peak power". These descriptions are again deceptive and in Europe they are misleading. I would advise you to e-mail Trickfish and ask for the output power rating for the 1K Bullhead in wattage units AES (Audio Engineering Society based in New York) or the wattage units RMS at the lowest level of distortion. Likewise, for the power handling of the TF112 - AES or RMS. Additionally, request a statement of efficiency such as 96dB @ 1W @ 1m. If weight is more an issue than bass volume, then you need to get a sack barrow / trolley preferably with pneumatic tyres. The models with 3 rotating sets wheels for going up & down stairs could be beneficial.

Did the 2x8 section stop working abruptly or did you hear any rough noises before it stopped for good? If it just quietly failed, then you need to check the wiring from the input socket and on via the crossover (probably on the reverse side of the rear connection panel) through to the 2x8 section. Loose wires or broken connections/solder joints. Possibly a component failure on the crossover. If you heard rough noises and or there is a scraping roughness when you push the 8" cones in & out, then you may have more damage then dodgy connections. I'm sure there'll be more contributors later with more expertise than me, but as a start it's "get your screwdrivers out time". PS. CHANGE YOUR FORUM NAME PRONTO. YOU'RE IN THE PUBLIC OPEN SPACE BEYOND BASSCHAT SO YOUR E-MAIL IS VISIBLE IN ANY SEARCH FOR "PEAVEY". MODS.

Jakester, For the benefit of the community, let us know the name of the seller and category of goods you initially bought. Then we can all avoid them in future.

Hi acidbass, If you haven't already bought the Eminence then I think you ought to look at this 10" from Beyma. It looks to be a bargain. https://www.bluearan.co.uk/index.php?product=Beyma_10WRS300_10_inch_300W_8_Ohm_Loudspeaker_Driver&id=BMA10WRS300

Help is at Hand !!! Go ahead and buy it / them ...... Then sell it on to me for a 90% discount. That way both sides of your brain will be back in equilibrium. You bought it but you didn't. I'll be happy, you'll be happy and the repetitive posting will cease. Light up a cigar and relax ......... your finances will be so much healthier. See; it feels better already, doesn't it!

Just get a damn good trolley with pneumatic tyres. The smile on your face when start to play will banish all sense of pain in the back. Enjoy.

Try here - https://celestion.com/speakerworld/dr-decibel/ CLICK HERE and ask the "doctor" a question. Just copy & paste your basschat post into the box.

First of all, consider the need for an entrance lobby, if possible with the gap between the sets of doors set as far apart as is practical. The walls to this lobby should be lined with a suitable sound absorbent plaster board that meets the Fire Officers recommendations for use in a "means of escape route". Is there another door to act as "means of escape"? As for the walls it's battens up, probably 2 x 2. Fill the wall gap between the battens with 12mm fibreboard. Across the battens you need sound absorbent plaster board such as this:- https://www.insulationsuperstore.co.uk/product/british-gypsum-gyproc-soundbloc-with-tapered-edge-24m-x-12m-x-15mm.html or this https://www.insulationsuperstore.co.uk/product/knauf-soundshield-plus-plasterboard-tapered-edge-24m-x-12m-x-15mm.html Then seal up the gaps at the edge of walls & ceilings with a sound absorbent sealant. Windows? Extract fans? If you want or need a design for a sound absorber to a fan, it's basically an acoustic labyrinth. A long wooden box with a fold inside and lined with acoustic absorbent foam. The longer the better. Good for middle & upper frequencies, less good for bass, but better than a hole in wall.

The Celestion should not be written off, it's a perfectly adequate driver and you're questions are not stupid. If you're happy to go ahead and build a box and cut some holes in the panels then Chienmortbb and I can give you the dimensions for the box and the ports. As has been said before elsewhere, designing a speaker is matter of endless compromise. For example, reduce the size/internal volume of the box will cause the sound response to increase in the low-mid bass, make the box too big and overall power handling suffers. Make the box too small and the optimum port size can change to something impractical, and on and on etc,. In this case I would advise you to make a box to Phil's basic dimensions but extend the top, bottom & side panels so that they are 25mm deeper, back to front. So the panel dimensions should be: Top & bottom: - 374 x 315mm Sides: - 450 x 315mm Front & back: - 450 x 350mm. That will give you a gross internal volume of 41.1 litres. One 4" / 100mm port should suffice. Chienmortbb will probably comment later.

Hello J Mac, The short answer is yes; it will work. Bear in mind that you will have to change the port sizes from Phil's original, as that was specifically designed to suit the Beyma driver. Don't worry about that. I & several others can do the calcs needed. In a 30 litre cab the Celestion will produce a slightly warm sounding bass, but with reduced bass output in the low bass below 100Hz. If your project is a get-you-going sort of idea and the special price is important then go for it. Phil has said elsewhere that the cab dimensions result in a volume over 30 litres, to account for the space taken up by the Beyma and it's ports. Going by his dimensions of 350 x 450 x 236mm internal, you get just over 37 litres. Once a 12" driver is installed and the ports fitted that will result in a net volume of about 33 litres. If the Celestion from a fellow Basschatter doesn't work out, then there is an alternative in the Fane Sovereign 12 300 @ £70 from bluearan.co.uk. Chienmortbb should be along later with some details.

Dave Grusin's 5 Original Albums box set. Bargain. Cost about £12.50 That classic STAX above looks interesting.

From your description it sounds like you have a Marshall 1553. A bit of a strange hybrid. It has even been asserted that the drive units are really for guitar and not bass. If you wish to persevere with it, contact Celestion and or Marshall, but the cost could be startling! Good luck.

Ross always comes out with hype like that. I wonder why? The cynic says there's also a chance Ross & his guests have the same management and he owns/controls the format of the show, so it's a circular benefit. Notice how many of his guests make repeat appearnces @ 12-18 month intervals.

The Celestion looks the best of those initial choices. That upper peak will not be audible as a full-on tone, but it might give a crisp edge / definition to the middle & upper bass notes. Don't concern yourself too much with the fundamentals down around 40 - 50Hz as what you hear is really the 1st harmonic at 82Hz. The Pulse 12 works comfortably in an enclosure of about 40 litres and the Basslite 10 likewise in a box as small as 28 litres. Bill's suggestion to try some more 12's is definitely worth a punt. For a 200 watt input, the Eminence Delta-Pro 12-450A will touch 123dB and the robust Beyma SM 112/N will exceed 121dB for a 200 watt input. The former costs £106 and the latter £110. With these latter two, they are so efficient you may not need to ever consider changing them. PS. The Beyma SM212 mentioned above will manage 121dB for £96. You pays your money and you makes your choice!

Hello adriansmith247, You have many variables in that question so it would help us if you could give some more information about your friend's existing set-up. What's the wattage output from the Polytone amp? What power handling is required for the Bass cab? What's the budget? The GK MB 150 1x12 combo you mention has a weight of 12 Kg or about 26lbs, so I guess you're looking for something less than that. Small major-brand bass cabs coming in under 12 Kgs are rare. The EDEN EX112 @gear4music comes close but still weighs 30lbs, so as you say, you're looking at brands like RedSub / SubZero. If your friend wants to continue to use his Polytone amp then there is sideways option open to him. That's to send the signal from the Polytone to the Effects Return socket on a combo. Only a few light & cheap combo's can do this but their speaker power handling is usually limited to about 30w input. For example: - https://www.gear4music.com/Guitar-and-Bass/RedSub-BA-30-30W-Bass-Amplifier/2KCW This weigh in at 11Kg. The SubZero GC 112, a guitar cab & looks adequate, can be daisy chained, but no weight is specified. The SubZero G 110 with a Celestion speaker is another guitar cab; is good for 30 watts & weighs 10Kg. Otherwise at a price there's the Gallien Krueger 112 MBX extension loudspeaker with aluminium chassis. Only 16 lbs, but £300!

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.