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About Balcro

  • Birthday 08/12/47
  1. 12" Drivers for custom enclosure..

    Hi there, As Stevie says, either Celestion speaker will work OK in that box. By the way, my calculations are that it's 167 litres gross volume. Just one other observation. It's a square box 27 x 27". Having an exact square dimension might well cause some unwanted resonances, so it's best to pad out one side of the box with hard polystyrene blocks if you can get hold of some. They take up volume without adding any real weight. Two to three inches should be enough. For every inch in depth of poly blocks you'll lose about 5.9 litres in internal volume, but in this case it's all to the good. No significant difference to the frequency response.
  2. After re-running the figures with the revised port length and a volume of 17 litres, etc., I agree with your general conclusion on the differences in response curves of the two drive units. The Eminence has the peakier / exaggerated response centred on about 135Hz while the Celestion is a flatter response by 2dB and centred @ about 115Hz. Marginally I would favour the Celestion. It might sound a bit less "one-note". Power handling for both units is well in excess of the original, especially in the low bass. The Celestion takes the full 250w rated power down to about 68Hz, the Eminence is similar except it has a dip to only 200 watts just around the area (125Hz) where it's output peaks. Balcro.
  3. Hello paulbuzz, Can you please check the dimensions of the cabinet in your possession. Your written dimensions in the first post do not tally with the dimensions in the diagram. Balcro.
  4. Thanks for the excellent diagram. I agree with your observations about changes to tuning & the frequency response. Yes, I am thinking of extending that lower shelf & reducing the 100mm gap. I shall re-calculate and give you the options. Will get back to you later. Balcro
  5. Hi paulbuzz, The Eminence spec sheet is really very broad. When you put the Deltalite II specs into winISD, the automatic calculation produces a very flat frequency response at a volume of 60 litres. Reducing the volume to 30litres still gives a reasonable response curve, however when you check the "Maximum Power" chevron the result is a disappointing dip to 80w down at 80Hz. Reducing the volume to about 17litres tips the response sharply upwards in the low-mid bass, throwing the system tuning out. The Celestion still falls foul of the fixed slot port, with a tilted up frequency response, but not quite so much. To restore some sense to the situation you could retune the port quite easily. In other words reduce the 100mm gap at the back. Let me know the length of the slot port roof by measuring it's front-to-back internal length and I will recalculate. Balcro
  6. I've had a look at this in winISD and it looks like the Celestion is definitely the one to go for. My rough calculation is that you have an internal volume (ignoring the slot port) of about 17.20 litres. This rules out the Eminence which would prefer at least double that volume. The Celestion handles 150+ watts all the way down to about 48Hz, while the original Elder Audio driver you have quoted (with a 50w input), dies at about 190Hz, bottoming out at 35watts on 90Hz! The Celestion goes louder for a given input and with it's larger xmax has much greater "headroom" at low bass frequencies. If anyone would like to cross check my findings I'm more than happy.
  7. Nothing bad to say about them. Some of their prices can be surprising. I bought my Cort Bass from them 5 years ago. Prompt delivery in about 5 days as I recall. The credit card company made a call to me as the location flagged up as an unexpected usage location. That's was fine by me. Balcro.
  8. Acoustic 360/361 Vintage

    It's best to start here:- [url="https://www.tapatalk.com/groups/unofficialacousticcontrolcorpmessageboard"]https://www.tapatalk...orpmessageboard[/url] There are lots of people on this forum who give you all sorts of information & answers about "Acoustic". This other link also looks interesting:- [url="https://acousticamplification.com/history-of-acoustic-amplification/"]https://acousticampl...-amplification/[/url] Then get over to youtube and see all the videos about the amp and the 360/361's. Then wikipedia. If you wan't to know the tone, see this - [url="https://www.youtube.com/watch?v=EGuEagHDL9M"]https://www.youtube....h?v=EGuEagHDL9M[/url] - he saves the best 'till last- play it loud! Balcro
  9. Cabinet Port Sizes.

    There's a further complication to do with wiring and it bears on my comment about power handling. Do think about this before you decide to go ahead and bi-amp the 2 x10 cabinet with the 15" cab. See Phil Starr's post #22. Check the label on the side of the Deltalites and the 15"unit. It may make the mating of the 1x15 and the 2x10 even more impracticable. See search term "Power handling of a 2 x 10 speaker wired in series". Lots of answers, but as far as I can see you can only wire (in the case of the 2x10) 2 drive units in series or parallel but not in series/parallel. If you have any doubts, come back to the forum and double check with an Ohm wizard.
  10. Cabinet Port Sizes.

    Here's one I prepared earlier.......... an old winISD file. 2013 to be precise. I can't remember why I did it, but it saved a bit of time. Back then I was working with an internal volume of 29.5 litres. Fortunately the T/S parameters for the Eminence Deltalite 2510 II have not changed over time. All I've done is change the volume and the program re-calculates the ports etc. Assumptions for the calculation: 1. The panel through which you're going to cut the hole for the port is 18mm thick. 2. The internal diameter of the plastic port is 110mm (11cm) and the external diameter is 120mm (12cm). Gross Internal volume 33 litres. Minus the volume of the Deltalite - 0.74 litres and minus the net area occupied by the port - 2.16 litres. This leaves a net volume of 30.1 litres. This gives an overall port length (from the exterior opening to the end of the port on the inside) of 20.96cm (8.25"). Port tuning works out at 57.06 Hz. With a 90w input, port velocity is about 14 metres per second. With a configuration of two 1 x 10's that input is a safe but conservative [u]estimate[/u] for general operation For a graph of how this looks, see the link on Phil Starr's post #10. It's very close to that. Not optimum but more than workable for a standalone 2 x 10 or more correctly 2x (1 x10) in this case. Good enough to dispense with the 1x15. For the best results, consider using the 2 x 10 on it's end i.e. one drive unit above the other. If that is not practicable for one reason or another, then ignore that last point & use it horizontally. Now decide where to place your ports. Don't place the port outlets on the bottom of the cabinet; 15mm is nowhere near enough to allow the ports to "breathe". There is a technical minimum for this; it's probably related to port diameter or something, but I can't remember which, so play safe and don't place any obstruction within 8" of the port opening.
  11. Single 12" bass Cab

    Downloaded that latest version of winISD from the facebook link and the home-page, but Norton Anti-Virus took umbrage with it on both occasions. Something called Heur.AdvML.C was identified and it was removed to the vault. ?
  12. New neighbours threaten venues future

    In my previous life as a sound-level meter carrying professional, I have sympathy with you and the venue. It looks like the new owner is manipulating 100 year old case-law to make more money from his investment. Rushing around with a sound level meter and making a big hullabaloo looks like deliberate scare tactics, and any sound level reading he has taken will not be repeatable in court. Only the judgement of an independent professional from the Local Authority would carry any weight. There's a lot more to "Noise Nuisance" than a simple uncalibrated sound-level reading from an untrained whinger. Presumably the building is an obvious music venue with advert boards or posters outside that are clearly visible to the general public and has a Public Entertainment Licence. The venue owners need to stand firm and not be intimidated. The venue owners/manager could consider contacting the local authority and enquire if they have received any complaints.
  13. Selenium speaker for a Sealed Cab

    Hello hrnn1234, I've just checked this speaker out on winISD and it comes as no surprise that it is totally unsuitable for bass guitar use. It's a Bass-Mid P.A unit and only handles the nominal power down to about 200Hz !! xMax is feeble at 1.29mm. Below approx 200Hz, xMax was exceeded with a 50watt input! Others may may come along later to give you advice on similarly priced alternatives that are suitable for a closed box. Balcro.
  14. Replacement speaker for GK MBE212

    Hi lagartortazo, Having checked out all the choices on your list with winISD, I can't find any that produce a good response in 39litres (half the cabinet net volume). As Phil Starr has said, the Beyma 212 works well enough to be usable. Without touching the existing second port it will have a tuning frequency of about 51Hz. However, it will change the sound balance of the system because it probably has more low bass than the original GK unit but is probably less efficient (a fraction less loud) overall. See winISD graph of the Beyma in 39litres of air space. Double click on the attached thumbnail picture. Over here the Beyma is about €100. You'll have to wait for the reply e-mail to learn the cost of a GK original. Good luck. [b]PS. Don't forget to check that the speaker mounting holes of any replacement are the same diameter as the GK originals.[/b]
  15. Replacement speaker for GK MBE212

    [quote name='lagartortazo' timestamp='1489788265' post='3259960'] Around 125 litres, and port measurements are 12x24cm Thank you [/quote] Using your dimensions, I get a nominal internal volume of about 83 litres. Looking at the GK site for the MBE(ii) the internal dimensions appear to be about 115 litres. In both cases there needs to be an adjustment for the volume occupied by the speakers, bracing, port(one or two) and the drive units. Can you confirm that the dimensions you quoted are internal. Balcro.