Balcro

[quote name='Bill Fitzmaurice' timestamp='1395509842' post='2403254'] On the outside, so that the air volume within the duct contributes to that of the enclosure. BTW Balcro, move up to the W7 version of WinISD, there are a lot more options, including max power, max SPL, and port velocity. [/quote] Hi Bill, I understand the option, but I advised on an inside mounting as the volume taken up by the port has already been accounted for in the enclosure net volume calculation of 123.6 litres and Eminence's recommendation is for 119 litres. Still, it's only a gain of 1.2 litres, so won't make a great difference. Putting it on the outside may well be practically & cosmetically easier with no chance of damaging the port tube. Thanks for the tip about the Windows 7 version. I'll look it up. It's a couple of months since visiting Linearteam, being an XP luddite. Regards, Balcro.

Hi Geoff, That's correct. Just cover the end of the port on the inside. Balcro.

Good morning Geoff, Ah! The effect of using 4 ports - There's a very small boost, maybe 0.2 of a decibel, to that flattened frequency response curve between 100 - 200Hz. Minimum power handling dips by about 0.4 watts, cone excursion is unchanged, and Port air velocity (assuming a 150watt input) drops from an already low 13.5 to about 10.5 (not sure of the unit in this case). These changes are clearly of little importance. However, using 4 ports puts up the required port length to maintain the same tuning; it rises to 24.4cm, which means you would have to lengthen all 4 ports. It's easier to just cap off one port. Putting in 150 watts as a test input, winISD calculates that the output at 100Hz will be about 123dB!! Extremely loud. You're also within the 4.8mm xmax limit @ 73Hz (see the red horizontal line). It's surprising how little input you need to make a big noise. The middle picture shows the power handling with the revised internal volume. The 3rd pic below shows the cone excursion. Xmax is exceeded at about 41Hz, but unless you're going to play at deafening sound levels with a full-on octaver, you'll probably never reach it. I've re-checked the volume figures overnight and have now calculated the internal volume to be 123.6 litres. See the l/h picture. This has had a negligible effect on the curves. Enjoy the noise. Balcro.

Hello Geoff, These graphs show the frequency response for your existing set-up with the Deltalite. I've only used 3 of the ports. Using 4 sent the port length to over 24cm.

[quote name='geoffbyrne' timestamp='1395435188' post='2402567'] The 4 ports are 100mm diameter and the tubes are 165mm. You're doing a great job, mate. G. [/quote] Your welcome. Gotta Dash, back after 11.30

Hi bubinga, From the days before music videos were a fact of life. Put together with very little practice and with very basic recording techniques, so by todays standards it lacks polish. It's just makin' music! Harvey Brooks on bass. http://www.youtube.com/watch?v=CdMf-86Evro http://www.youtube.com/watch?v=YSqlUYkx8d0 This last one , because it was of the moment and with all the passion. What a drummer. did they ever play it better http://www.youtube.com/watch?v=pNslkIdyprw Balcro.

Hi Geoff, I've just re-run winISD with the Deltalite parameters. Looks like a nice fit at 120 litres. If you can give me the exact internal diameter of the port(s) I'll check it again. Balcro.

Hi Geoff, Well spotted Bill. It looks like you need to double check the exact description of the drive unit. Are there any other labels or codes apart from "2515" attached to or printed on the chassis. Let us know. Balcro.

Hello Geoff, I ran the parameters of the C2515 (2014) through winISD and quite closely matched Eminence's own "Cabinet design" for a large vented cab - (3.9 cu.ft). See here: - http://www.eminence.com/pdf/Basslite_C2515_cab.pdf To my mind the mix of large cab and this Basslite is not a marriage made in heaven, but the Basslite is flexible in it's volume requirements. Power handling dips to just over 100 watts at 70Hz but at the same time the driver is very efficient. At that frequency with a 100 watt input it is putting out around 119dB!! Loud! If the internal volume is reduced to 91 litres, power handling rises to a minimum of 120 watts. Output still exceeded 119dB @ approx 78Hz. In either case I set the tuning @ 46Hz but there was no visible difference in overall frequency response - big boost in the low bass - 80 - 160Hz. By my calculations your potential cab has an internal volume of about 121 litres. It'll work fine in nearly all situations, but the indications are that it has it's technical limitations. I'll post some graph pictures later this evening. Balcro

Hi Geoff, I presume you want to check the tuning and the installed driver or the driver to be fitted, is an Eminence Basslite 2515. Is that correct? Are those ports really 200 mm deep? Balcro.

Thanks for the tip. Now securely recorded. Balcro.

Sorry to hear about your predicament, but I'll echo what bubinga5 said. Put the guitar down now!! That sounds like you've done a lot of damage (probably work as well as play). I would use whatever pain killers the doctor advises and as a minimum, support your fore-arms and wrists with something like an elastic bandage. At least they keep the arms warm and remind you that you arms/hands aren't 100%. When she has a flare-up, Mrs Balcro occasionally uses those semi-rigid wrist supports with the velcro fastening for her arthritis related condition. Good luck with the op and take time to recover afterwards. Then I suggest you go see a local tutor and get your posture / technique / guitar position / strap etc., checked out Balcro.

Further to what Horizontalste said, looking at the numbered Page 8 of the Behringer "Quick Start Guide" for the 502 mixer, it shows what they call a typical "hook-up". Once magnified, you can see that they've included a DI100 D.I box between the bass guitar and the Line-In socket. Is that necessary or can "Evil Undead" just go direct to the line-in socket? Alternatively, I've long been thinking about the Behringer "Guitar Link" UCG-102. This looks even simpler but still offers a USB connection from a PC, mp3 player or tablet. as well as guitar-in and headphone socket. Does the mixer offer any small level of amplification compared with the UCG-102? Question for Evil Undead. Do you keep your music tracks on a PC / laptop or just the iPad? Opinions anyone? Balcro

In theory it's the latter - 250 watts into 6 cones. However it's not the watts that count, it's the sensitivity of the speaker boxes or speakers in the combo. The Minimark 2x6 combo has a [u]claimed[/u] sensitivity of 101dB per 1 watt input. If you add that to the 604 cab which has a claimed sensitivity of 100dB then IN THEORY you should get 103+. (I've forgotten how to do the fiddly maths to give an exact theoretical result - it could be 103.1 or 103 .2, something like that ). Meanwhile the LMK into the 604 is set at the 100dB sensitivity of the 604. The extra 50watts won't make up the 3dB difference. Balcro.

Well, here are the results of the Luxembourg jury! I've put the 3 drivers on your list and a later incarnation of the Celestion BL10-200 called the 200X into winISD. All the drivers - paired - appear to be comfortable in a ported enclosure off 55 litres, which is roughly what you have there. That was standardised and the system resonance adjusted in all cases to be at or just above the "Fs" of the driver. The Eminence OEM driver is shown as the cherry red line. The BL10 200 is shown in white. The BL10 200 X is shown in green, and The Eminence Delta 10 A is shown in blue. The first 3 have an overall similar shape of bass response and have an efficiency to produce about 94dB for an input of 1 watt. The Delta 10 A although it appears below the others is a little more efficient, (it's graph / curve is overlaying the datum line set by one of the other drivers) perhaps 2dB and has a stepped or shelved response in the low bass. The Delta B although not shown has a similar drop off in response to the "A" without the flat shelf section. Neither Delta has a low bass response like the OEM unit. Remember this is only a guide to the response of pairs of the said drive units. If you find one of the drivers is faulty, then it seems to make sense in this case to replace a faulty Eminence with a new Celestion BL10-200X as the general behaviour and response and efficiency is very similar to the other BL10 200 (no X). If the Celestion is faulty, it's very difficult as you will not be able to get a matching Eminence OEM driver unless you can find one second hand.

Hi grayn, Isn't that a GB94 and not a GB4? Balcro.

[quote name='tm486' timestamp='1391538582' post='2358345'] Hi, I've got responses back from both Celestion and Eminence. I've been sent the data sheet for the BL10-200 and the OEM driver in the Yamaha BBT210s. Eminence said that their most similar stock item is the Delta-10A. Having checked the specs on the OEM driver sheet against those of the BL-200 and the Delta-10A, the BL10-200 looks very similar to the Delta-10A, but neither of them seem to be very similar to the OEM driver. I've made a little table of most of the 10" drivers from Eminence and the BL10-200. I can see that a few of them have some values similar to the OEM driver, but I don't really know which values are the most important to pay attention to. Can anyone tell me which values are the most important when choosing a replacement driver? Thanks, Tom [/quote] Hi Tom, Hi tm486, Good to see that you have the info. The OEM unit appears to be set to give a little more low bass than the standard unit. If you can give me a guide to the following factors, then I can do a rough winISD calculation to find out the bass response of the driver in the cabinet. 1. The basic internal dimensions of the cabinet. 2. The combined frontal area of the slotted port openings. 3. The depth of the slot - how far back the slotted opening extends. Balcro.

[quote name='redstriper' timestamp='1391554584' post='2358641'] Why does a cab have to be less sensitive to be more bassy? [/quote] In the simplest terms it's because of interactions between 2,3,or 4 of the Thiele / Small parameters. These determine everything that happens. The lower the fundamental resonance (Fs) the greater the ability of the drive unit to produce low bass, e.g 40-80Hz at the same sound level as it does at 100Hz. The slope down from say 100HZ can be gradual, steep or shelved, it depends upon the system tuning, but the result is not in doubt. You have a given strength in the magnet / motor-assembly. A powerful magnet will exert great [u]control[/u] over the movement of the voice coil and hence the back & fore movement of the speaker cone. If you make the cone heavier, the motor assembly still remains the same, likewise the front and rear suspension of the cone, but stopping & starting the cone (back and fore) is harder because of the increased moving mass of the cone. The result is a lower Fs. To move the increased mass of the cone as far and as quick as before, you have to increase the electrical signal coming in (more watts needed). The drive unit needs more power input to sound as loud as before. It's less efficient. This is analogous to taking a modern European car. Without changing anything else, stick 200Kgs more than normal over each suspension point and it will behave like a 50's American sedan. It'l bounce up and down. How do you make it go as fast as the European car; you put more power in with a bigger engine! Well it's something like that. Balcro

It sounds as if the 4x10 could have been tweaked as well. Check to see if the speakers in there are likely originals. If you contact Eminence or Celestion tell them the drive units are in a ported cabinet and the approximate internal volume. I don't know too much about rattles but check the obvious like the drive unit screws / T-bolts and loose wires vibrating on the chassis or loose wires at the jack plug end. Then there's the fastenings for the front grille. If you have access to the front of the drive units you can do a simple test for a misaligned coil by pressing evenly on the forward edge of the cone. If there are no special noises then it's probably OK but if you hear a rough scraping or rubbing sound it suggests all is not well. Compare the 2 drive units. Can't tell you the best clever way to check for driver distortion so hopefully someone else will have that knowledge. I don't think you have a big problem, it may just be one small weakness somewhere. Balcro

In respect of the unknown Eminence driver, why not send Eminence an e-mail via their "Contact Us" link & on to Customer Support. As the drivers are probably OEM they won't disclose the exact spec, but give them the full set of numbers and they will probably advise you on a suitable alternative as a replacement. From the look of it I guess that 2x10 cabinet has an internal volume of 55 - 60 litres. The Celestion may be marked up as a BL10-200, but the latest model is a 200X. Try the same with Celestion and ask them for info on your driver, quoting any similar marks on the chassis. Secondly, it seems you have a probable power handling imbalance. As each cab is 4 Ohms you are potentially sending the same power to each cab. Are both cabs rated @ 200 watts? Even the 4x10? Balcro.

Welcome to the club. Balcro.

Hello EU, After a quick surf and thinking of a reasonable price I would consider the MBE 210 II amongst these:- [url="http://www.gallien-krueger.com/products/combos/"]http://www.gallien-k...roducts/combos/[/url] They have the required sockets, the price is moderate (£470 @ gak) (you can find cheaper but not necessarily lighter), they're quite efficient (loud) they only weigh 35lbs and have an 8 Ohm extension-speaker socket on the rear panel. However, from what I remember they have a particular "eq" arrangement, so you have to be prepared to read the manual and persevere with getting the sound you want. Balcro

Must admit I've done a lot of tinkering on WinIsd with models ranging from single 6.5" to huge 4x12's. Everything from coffee-bar / sling'em over your shoulder boxes to stuff for upright/double basses. Finding good matches where mids-tweeters are needed is not easy and bringing it in under-budget can be just as tricky. I think the upright bass community are poorly served by current commercial offerings. So how about that for a later project. Good luck. Balcro.

http://www.gak.co.uk/en/korg-ga-1-guitar-bass-tuner/30612 Does the job.

In the interest of balance I think this poll should be repeated for every brand of Loudspeaker manufacturer. This carping on about relatively small issues on one brand is tiresome. Can you imagine the Americans carrying on like this about one of their own. My own Ashdown 5-15 has a lightweight handle that looks fragile and probably wouldn't last as long as the rest of the box. The carpet finish attracts the dust as well as the cat! It's shape, combined with the handle position makes it awkward to carry and very hard on the wrist, but it's adequate for my indoor needs. It doesn't have any internal damping panels. It's slightly honky and boomy all at the same time. Getting it to a bass-bash requires a lengthy drag from the upstairs bedroom and a sack-barrow/trolley to the car. It's a compromise. Barefaced cabs seem to have far fewer compromises and have a particular focus on light weight with a definite appliance of acoustic science and engineering. This R&D, choices of particular materials and small-scale manufacture costs money, but it achieves the design brief. Many other "big brands" out there don't seem to apply much acoustic science or engineering beyond the bare minimum. It's all about showroom appeal. Personally I'm equivocal. I've heard others play them at 2 bass-bashes. Not heard them anywhere else. They make a big sound. Couldn't find a question box that fits my overall opinion. Could have ticked boxes 2,3,4,9,12 and 13. I settled for one. Balcro.