Phil Starr

[quote name='stevie' post='828509' date='May 5 2010, 03:11 PM']I’m not really a great believer in optimum cab sizes. Ported cabs for bass guitar are quite flexible in terms of what works. For example, all the speakers I listed will work quite nicely in a 35-litre cab although, as you mention, the Fane is more comfortable in a smaller cab than the pressed steel Celestions. In response to your question, I haven’t got a lot of personal experience of the Chinese Celestions. I’ve tried a couple (not the bass guitar ones), and they were better than I expected - certainly better than the older Celestion PA speakers I have tried. Other people I know have been impressed with them. Whoever is designing their drivers is very capable. I’m impressed, for example, with the way the top end is very controlled – unlike many drivers which go into uncontrollable spasms before they roll off. I understand what you mean about the high resonant frequencies. 73Hz does sound too high, although this is largely a factor of the suspension stiffness. Also, the Qts of this driver is relatively high, which compensates. You could drop the resonant frequency by fitting a softer suspension, but then Qts would drop, VAS would rise and you’d end up with exactly the same performance. I modelled the two pressed steel chassi Celestions, one with 73Hz and the other with 64Hz resonant frequency and their low frequency performance was identical. If I were choosing from the three pressed steel drivers based on their parameters, I’d go for the Fane as you did because the heavier cone helps it produce more bottom end. Oddly enough, the parameters of the Celestion NTR driver are very close to those of the Fane. Although the NTR is a very expensive option, it is probably in the same class as B&C, 18Sound and Beyma. 4mm coil overhang is quite acceptable for a 10 - even the JBL 2226 only has 5.5mm of physical overhang. If it were a B&C or an Eminence, the spec sheet would say 8mm xmax. What do you think the problem is with the top end of the Fane, Phil? Have you measured it?[/quote] Hi Stevie, I lost track of this thread over the Summer what with gigs and holidays. Yeah I also modelled the two Celestions. I haven't got round to measuring the Fane yet. In the end I couldn't make my mind up between the Fane 10-275 and the 10-125 so I bought two of each to experiment with and built them into a temporary 4x10 but with a partitioned cab and wired as two 2x10's. The Fane data shows a more extended top end for the lighter coned 10-125 with a smoother break up pattern and this is the speaker Fane recommend for bass guitar but because I have come from a hi fi direction I was attracted to the cleaner bass promised by the low Q and bigger magnet of the 10-275. So, I effectively have two 2x10's with the 10-125's in undersized cabs tuned to 55Hz and the 10-275's in optimum cabs (SBB4). the only testing I've done so far is to play bass through them. Firstly I'd confirm what you say about optimum cab size. The modelling on the undersized cab shows a real hump of just under 3dB (from memory) but the bass sound when playing isn't dramatically different from the 10-275's. Certainly much less than that caused by tweaking the eq or changing strings The 10-275's do give a more clean and controlled bass, but again it isn't dramatic. I doubt that it would be noticeable once the band get playing around me. They also roll off at about 3000Hz and their is no dramatic resonance peak unlike the Celestions or equivalent Eminence speakers so they don't sound particularly lively and I play with my 15" Peavey driven cab on top to pick myself out of the mix the 10-275's are very bassy and the Peavey gives a lot more mids. Finally they weigh a ton and a 4x10 with these in will be a hell of a lift. They do make for a nice small box though. I'm not the worlds greatest bassist so the speakers haven't had much of a workout yet. I'm going to do some measurements and try out an optimum sized 2x10 with the 10-125's which sound better than I expected in the undersized cabs. I'm also intending trying the 10-275's in a 2x10 on their own to see if they are up to the job as a compact cab. My wife is going to kill me.

[quote name='gilmour' post='942368' date='Sep 1 2010, 05:10 PM']Sadly no - the insurance company are really dragging their heels, it looks like the whole thing will have to be replaced as not only is the screen damaged but the CD drive is knackered and the hard drive corrupt So I only have intermittent internet access.[/quote] Bad luck

Interesting, I've got the same sort of problem with my Cort. I spent a lot of time fiddling with pup heights and eq settings but could only mask the problem. I mainly use Rotosound 66's and when these are new the problem isn't so pronounced although I am still aware of it whatever the strings. I've even thought about upgrading the pups but without the promise of a cure it seems a lot to spend on what is basically a cheap bass. Is this a common problem with P-bass pickups?

Got that laptop fixed yet? Hope so, I can't be the only one looking forward to the next post.

I used to build custom cabs. Materials costs for a cab would be £30-£50 for a basic finish + about 6 hours labour for a one off cab. All very approximate as it depends upon the cab design and to a lesser extent how much expensive gear you have to speed up the build. The box is going to cost £100+ to build. A cheap Celestion or Fane driver will be £30-40ish up to £100 for a Precision Devices driver of someting else a bit better for a 10" unit. Add in the time it takes to market, talk to the customer, deliver,test, provide after-sales support etc. Also allow for the costs of renting and equipping a workshop and it is pretty difficult to produce a speaker for under £200. Add in the costs of shipping and the profit margins of the retailers/wholesalers and/or importers and you get a retail price of £400. Mass production in China can cut the costs to half of these prices but such speakers are usually engineered to keep costs low with a compromise in performance. Having said that the engineering is usually well thought out and great value for money. Sadly very few people in this business from the musicians upwards make good money, we all do it for love first and sometimes manage to scratch out a living.

I don't think this is what you should be looking at for this function unless you think you will want to use it with a full band at some future date. Something like this [url="http://www.amazon.co.uk/Yamaha-Stagepas-300-P-A-System/dp/B000RW037G"]http://www.amazon.co.uk/Yamaha-Stagepas-30...m/dp/B000RW037G[/url] is much better suited. It sounds great with vocals and acoustic instruments and is amazingly light and portable offers you all the mixing you need and reverb on vocals if you want it and is really simple to use. The only minuses are that it won't go to rock band levels and the stand mount points (you'll need stands too) are non standard so you'll have to buy adaptors. We have one which we use for a full band in rehearsal and as our monitors at gigs. You'll have some quality kit and can then spend whats left on decent mic's

I'm following this with interest mainly because I want to see what you all think of the piezo arrays. I love the simplicity of piezos and they sound ok to me except that the sound output is ultimately limited as is their power handling. The array gets around this but I've always suspected that with the spacing of the drivers corresponding to the wavelengths of sound they are reproducing there will be serious interference problems. It's a problem with all line source arrays. I guess in the end I will have to try it out myself but with Gilmour building these ... Another solution I've tried is these [url="http://www.bluearan.co.uk/index.php?id=SKT902490&browsemode=category"]http://www.bluearan.co.uk/index.php?id=SKT...semode=category[/url] Which screw in to a standard horn flare [url="http://www.bluearan.co.uk/index.php?id=SKT902384&browsemode=category"]http://www.bluearan.co.uk/index.php?id=SKT...semode=category[/url] I've tried these with some PA speakers I built and for the price (£10ish) they are remarkable. They claim 105dB/W though I measured them (very roughly) at 103. I used series caps to reduce the voltage across them to use them with a 500W amp and to match them with the bass drivers and of course tried them with my bass. Bloody fantastic if you like a DI'd sound.

You mention pokey and hi-fi. If you mean a flat sound then why not use a PA speaker. They usually handle bass pretty well and often go lower than a bass cab and being produced in large numbers they work out pretty good value for money. I use a 12+horn PA speaker for smaller gigs and if I'm honest it sounds much nicer than my 4x10 + 15. If you go for an active version then the drive units have built in protection so you won't need to worry about blowing anything. Most bands have some sort of PA so its pretty easy to try this out without spending anything up front.

[quote name='Dom in Somerset' post='898088' date='Jul 18 2010, 02:50 PM']I'm about to order the electrics for my latest project, I know nothing about the subject, happy to follow a wiring diagram. CH guitars do wiring kits for certain basses and guitars, they do two for Jazz bass, one with a ceramic capacitor one with poly- what difference does it make (if any?)[/quote] going back to the original question I really don't think it will make an audible difference. In high end hi fi you wouldn't use a ceramic but you really aren't going to hear a difference through a bass amp/speaker. I recommended poly because I've found them more reliable. [quote name='stevie' post='910572' date='Jul 30 2010, 07:36 PM']Despite thousands of unsubstantiated claims to the contrary all over the internet, yes. The driver itself changes quite a lot, but its real-life performance in a box doesn't.[/quote] Actually this isn't true. The sound does change and you can hear the changes, they can be subtle or quite dramatic depending upon the speaker in question. Its not all down to Thiele/Small small signal changes either. Stevie is right about changes to Vas and Q being to an extent self cancelling and this is discussed in Bullock on Boxes (ISBN 0-9624191-5-X). These changes affect the bass response a little. More important i suspect is the changes in the cone itself which will soften with time becoming less rigid. It will flex more and resonances will change which will change the upper frequencies. Having said that we are all discussing angels dancing on the heads of pins. In reality we all use speakers for more than a few hours so they all get 'broken in' eventually and one person's dramatic change is another's subtle difference. Our hearing also makes fools of us all at times. I think where Stevie got us all so excited was by giving us actual data, a rare commodity on the internet. When I get time I'm going to have another look but for now I really ought to get some practice done. Great debate guys, I dread to think what it says about bass players.

These problems are caused mainly by resonances. Different rooms and structures will have resonances that emphasize different notes that will in turn be picked up by a mic. These resonances will be dependant upon the wavelength of the sound and simply moving the drums, bass stack or mic may well sort out the problem. Obviously a bouncy stage will also resonate. If you get this problem again then try setting it up so that the resonance is just starting and then try moving things around a little. You should be able to shift the 'hot spot' so it doesn't coincide with the mic in question. You could also try using the tone controls to tune the problem out. If you use a combo then try using a stand to point it at your ears. You get better monitoring and the stand will help decouple the amp from the stage.

[quote name='stevie' post='909493' date='Jul 29 2010, 05:55 PM']Here is some data on an Eminence Kappalite 3012LF, with measurements before and after running in. There are a few minor discrepancies, but this was not designed as a scientific exercise: I was simply checking the parameters against the manufacturer's figures. The parameters on the left are for the new driver; the ones on the right are the same driver, but run in. The interesting information is on the right - a simulation of how they perform in an identical box. I can't say this is conclusive and absolute, but it's certainly repeatable by anyone who wants to do so.[/quote] Love the thread and this is interesting data. The figures show the sort of increase in compliance you would expect after a breaking in period though why Qes would change beats me. The cone and surround of high power speakers are usually made of plant fibres (in turn made of lignin and hemicelluloses) and this is normally treated with some sort of latex or plastic. The spider is usually some sort of treated woven cloth. The fibres vary in their strength and some will break when subjected to repeated vibrations. The weaker ones will break early on and the process will continue throughout the life of the speaker until the surround (usually) fails. In addition you would expect there to be gradual chemical changes in the polymers used. All this means that there will be gradual changes in the mechanical characteristics of both the suspension and cone of the speaker throughout its life. This will be most rapid early in the life of the speaker which is what causes the breaking in period. I've noticed that the impedance/frequency curve of a speaker changes over time to the extent that I won't tune a reflex port until a speaker has had a period of use and you can definitely hear the changes in response.

Love my Peavey micro bass. look for one secondhand.

[quote name='gilmour' post='902509' date='Jul 22 2010, 11:08 PM']Found time to glue the arrays today. I'm pleased they look pretty smart. They still feel a little brittle but hopefully once the glues had a coupe of days to go off this will change, otherwise I'm not sure what to do. Anyone got any suggestions? Peace'n'hair grease R[/quote] You've left the flanges on the sides so run a batten along the back and fix the horns to the battens which will stiffen them up

You might find this useful [url="http://www.ultimate-guitar.com/columns/gear_maintenance/a_guide_to_fixing_intermittent_faults.html"]http://www.ultimate-guitar.com/columns/gea...ent_faults.html[/url]

[quote name='algmusic' post='899855' date='Jul 20 2010, 11:48 AM']I love this kind of bravery.. I just can't afford the risk of blowing my amp.. I've only done this once at rehearsal an played very quietly, but I always have the rule of getting a cab that can handle at least about 20% more than the amp, then you can drive the beast how you want... I'm sure you get a better sound.. well IMHP[/quote] I'm not that brave. I make my own speakers so the cost of a replacement drive unit is a lot less, plus I use meters on the output of amps and sound level meters to monitor whilst testing. In the end though the physics is pretty reliable. I suppose the point I am making is that you don't need to do anything other than take a lot of ratings with a pinch of salt. A 250W amp shouldn't be capable of blowing a 200W speaker in a month of Sundays unless there is tremendous abuse. The only exception to this is tweeters. When driven into distortion the bulk of the extra power will go into the speaker as high frequency energy and blow the tweeter if fitted. I haven't blown a speaker in nearly 40 years. [quote name='Mr. Foxen' post='899903' date='Jul 20 2010, 12:37 PM']Depends on what you mean by 'handle', and at what rating. Plenty of cabs won't handle 80% of their rated RMS power due to excursion limit at the frequency where cone excursion is at maximum. Exceeding the excursion limit is the bit that will break most bass guitar speakers, because you don't need to do it for a length of time, push the speaker past that limit and its gone.[/quote] Exceeding the excursion limit is a theoretical cause of failure but one that doesn't occur in properly designed musical instrument drivers. Remember that at high levels the coil moves out of the gap to the fringes of the magnetic field so the force moving the cone is reduced (causing distortion and loss of power.) At the same time the suspension will exert a much greater restoring force to the cone holding it in place. I can't think of a single example of a designer failing to allow for this and have never seen a speaker fail in this way. However reflex/sealed and open cabs require different levels of protection against this so I would avoid using a speaker in the wrong cab. you are qute right about speakers not handling their RMS power due to excursion limits though There are very few if any bass speakers that are not excursion limited at low frequencies and full power.

[quote name='270degrees' post='897331' date='Jul 17 2010, 03:03 PM']You're more likely to blow a cone using an underpowered amp. Just use common sense when operating the volume control. Also note that the speaker can probably handle more power than stated and the figure quoted includes a safety buffer of some sort.[/quote] This is one of the old chestnuts and like most it has a grain of truth in it. Assuming we are talking RMS or EIA watts or something similar the amp is rated on the undistorted sine wave it can produce for a few hours continuously into a stated load. usually nowadays it is rated on sine waves in the form of filtered noise called pink noise which is meant to be like music in its energy content. When an amp distorts the sound waves rise to a peak much more quickly, clip at the amps full power and then drop quickly. This means that on every wave there is more time at full power and the amp has more energy to handle and so does the speaker. The absolute maximum is a Square wave which contains 1.414 (root 2) times the power of a sine wave with the same voltage peak. So a 100W amp with total distortion will give 14oW in the speaker. It won't outpower a 200Wamp though. Speakers are rated differently. What destroys speakers is heat, 100W through a speaker means the coil gets as hot as an old fashioned light bulb. in the old days this melted the glue and the coil unwound, sometimes you even saw charring and smoke from a paper former. The EIA rating of a speaker is the heat it can dissipate for a few hours. It even assumes that the air can circulate freely in the test room and is at 20degrees. There is usually a peak or music figure 2-4 times the EIA rating, if this is done properly this should be the figure where the distortion reaches 10% and becomes audible. If you are playing normally then you have loud bits and quiet bits. The quiet bits let the coil cool down so the speaker can handle a lot more than its rating so long as it isn't distorting. If you play with a 40dB range (no compression) your 500w amp is only putting an average of 5W into the speakers. If you use lots of compression and bass boost/distortion you probably still have a 20dB dynamic range and are only putting an average 50W into the speakers so don't worry about a minor mismatch unless you get lots of distortion. The physics is on your side.

Ashdowns only give half there rated power through the internal 8ohm speaker so adding another 8 ohm cab will give you roughly an extra 6dB. If you buy a cab you want to keep then this could be the start of a new rig and in the meantime you have something gigable. If you buy a top quality cab then you can add a head when you can afford it. If the state of the Ashdown is troubling you then they can usually be cleaned up. Stick any loose covering back down (sometimes it can be ironed back down as the heat melts the adhesive) Clean carpet with carpet shampoo and a suede brush for stubborn stains. Any vinyl comes up a treat with a wipe with a clean cloth and WD40. Replace any damaged corners with a new set.

Go for the polyester or poly propylene, Don't use ceramics

You've probably got more than enough leads now but Mansons in Exeter is always a joy to visit if you are into guitar/bass ,and does a good job and there is a guitar tech at Westside music in Taunton (who actually showed me how to set my neck up)

Enjoying this thread, keep up the good work!

Its worth looking at something that runs off batteries if your like me and just want to set up anywhere to practice.

I do most of my practice with headphones. The most important thing is the quality of the headphones. Good over-ear headphones are needed, I use Sennheisers though my daughter's £30 Sony are nearly as good. Any cheap mixer will do the job as a headphone amp and a mixer gives you the possibility of playing along with backing tracks/drum machines. I use a very cheap 4 channel mixer designed for dubbing sound onto Video but have used a DJ mixer. Even my cheap mixer sounds much cleaner than any stage amp or even DI into the PA. The headphones go deeper than any currently available speaker (20Hz) and are clean all the way down, they also go up to 20,000Hz. The result is that you hear yourself very clearly and every little fault shows up. I think this is just what you want for a practice but it takes a little while to get used to the sound. I can remember seeing an amp modelling unit which had a built in drum machine and a headphone amp. I think it was a Boss. I didn't buy it because I didn't like the sound of the amp modelling but it would be ideal for headphone practice.

Why not get another Hartke if it suited you perfectly?

I'm not sure what you mean by depth of sound. If you mean more power then I'm not sure adding to your speakers in this way will help. You can't have a lower impedance and still match your amp and a higher impedance will lose power though it may increase efficiency, the best you can hope for is to stay the same as far as volume is concerned unless you change your speakers entirely. If it is the limitation of your 2x10 and you want deeper bass then the best way of doing it would be to convert your cab to 16 ohms (probably not difficult) and add another 16 ohm speaker. You could also take up the suggestion of an extra amp. It need only be a cheap PA power amp driven by your existing amp. Better still get the extra volume off stage and DI through the PA which avoids all the problems of the bass being pcked up by the vocal mics.

+1 for Ashdown being helpful. Have you tried another Speakon lead? It sounds like an intermittent connection and could be the socket but is more likely to be the lead. If you are my end of Dorset then Axe music in Axminster does repairs