paulbuzz

Since I have posted above criticising the common soundman's habit of "DI box first thing after the bass", here's my defence of the practice, just for balance: Modern amps/pedals etc tend to have very powerful EQ and effects which can easily produce a deeply unmusical or even unusable tone unless used judiciously and appropriately. There are plenty of bass players (as well as guitarists etc!) who have very little idea of what constitutes a good or appropriate tone in the context of the whole band. (People on this forum are probably an unrepresentative sample as simply by being here, we're self-selecting as the ones who care enough about such matters to want to discuss them with each other and hopefully get better informed!) Additionally, the sound coming out of the (most likely very coloured) bass cab may be completely unlike the DI signal from the amp/pedals which we are proposing to feed into the soundman's (hopefully quite flat & full range) PA system. So, for the busy soundman, the "DI box straight after the bass" strategy is an insurance policy against being fed an unusable sound from further down the bass-players signal chain; there's only so much that gormless bassplayers can do to screw it up with the controls on the bass itself! This is still really annoying though if, as a bassplayer, you have spent time and effort making sure that your DI signal does actually have a carefully considered and sensibly-sculpted tone!

Sounds like you need to head over to the 'Amps for sale' section to score a better amp! 😉 Alternatively, what on earth are you doing to them??!! 😮 The only time I've ever had an amp pack up mid-gig is when one of the new breed of supa-lite class D amps vibrated itself off the the top of the cab and crashed to the floor, snapping the input socket. When my old-skool Trace preamp did the same thing, it just kept on working (though admittedly it dented the floor pretty badly!)

I think the argument that "doing it this way it'll keep working even if the bass amp packs in" is a spurious one used by soundmen as an excuse to justify the way they wanted to do it anyway. There are loads of things on the stage that could potentially stop working and thereby screw up the show: the guitar amp, the keyboards, the drumkit (or drummer) might fall over, a mic lead might come unplugged - the list is endless - why worry about the bass amp in particular?

Firstly, apologies for resurrecting this old thread of mine a year later! 😬 As a brief recap, I was looking to upgrade the driver in my Harley Benton combo, which is identical to the Red Sub branded version and similar to the original Ibanez Promethean. My goals were a reduction in weight, extended headroom and ideally some extension of the bass response. The tricky part is that the cab is very small - it has an internal volume of about 17.5 litres (after allowing for driver displacement) and a port with dimensions of 25mm x 360mm which is 125mm long, leading to a cab tuning of about 85Hz. In the thread I got some great advice and options to consider, but in the end, a combination of inertia, penury and the 'leave it alone' suggestions meant that I didn't get a new driver. However, I'm now readdressing the issue, and so am back asking for further advice. I'm still considering the drivers I was looking at before: Eminence Deltalite II ( http://www.loudspeakerdatabase.com/Eminence/DELTALITE_II_2510 ) Celestion NTR10-2520D ( http://www.loudspeakerdatabase.com/Celestion/NTR10-2520D ) ... but the reason I'm asking for advice again is that my attention has now been drawn to this driver: Eighteen Sound 10NW50 ( http://www.loudspeakerdatabase.com/18Sound/10NW650 ) ...which is about the same price as my other options ( £129.95 from Lean ) but has a considerably higher Xmax (7mm) , and judging by its frequency plot, a significantly better bass response. I've tried having a fiddle in WinISD with this stuff, but my very sketchy grasp on these matters makes me very wary of any conclusions I might reach! So, my questions are: - would this Eighteen Sound driver be suitable for my purpose, or am I missing some significant feature that would make it unsuitable? - am I right in thinking that it would give me a more extended bass response than either of my previously favoured options? - any other suggestions for better driver options? In an attempt to make answering my questions less of an effort, I've attached WinISD profiles for the three drivers I've been looking at. Thanks in advance to any of the local speaker experts who might care to chip in! 🙂 18Sound 10NW650.wdr Celestion NTR10-2520D.wdr Eminence DELTALITE_II_2510.wdr

I have the humbucking version, which I imagine has much the same measurements. Have just measured the distance between the fitting screws as 78mm, if that helps. Personally I wouldn't recommend single-coil magnetic pickups for acoustic guitars; I've had far too many experiences of them picking up too much interference to be useable.

Extremely interesting! Thanks for pointing that out!

These exist (as an alternative to resistor-based dummy loads) : https://www.tedweber.com/gadgets/attenuators/speaker-motor-models As Bill and Bass Bunny said though, this doesn't come any closer to acheiving what the OP was asking.

Fair point! I was just trying to envisage a setup that came as close as possible to fulfilling the OP's original scenario. Not that I'm proposing to create a driver with switchable alternative voice coils!

The short answer is an emphatic "no". Slightly longer answer: The device you're imagining does exist. It's generally referred to as a "dummy load", and is essentially a big chunky resistor. Attached in parallel with the existing speaker, it will reduce the impedance seen by the amplifier's output, and thereby cause the amp to produce its full rated output power, as you suggest. However, this won't produce your desired result (more volume from the speaker), as the additional output from the amp will simply be dissipated (as heat) by the dummy load itself. To get more volume from the existing speaker, you would need to reduce the impedance of the driver itself, which isn't feasible in any practical way.

Ok, not a bug, but a feature that's irritating me, and not sure where else to mention it: On any of the topic/post listings pages, the 'tag' graphics are unnecessarily prominent - their bright orange colour on pages that are otherwise largely monochrome makes them much more eye-catching than the topic titles. This seems kinda weird for what's really a relatively minor feature, no? I would prefer them to be a fairly inconspicuous grey colour, so I can read them if I want to, rather than having them burnt onto my retinas... Sorry to moan, I know you've got much bigger fish to fry...!

Interesting! Another gold star for John at Orchid! I assume he incorporated one of the transformers that he uses in the isolator box that he sells as a separate item: http://www.orchid-electronics.co.uk/trans.htm

Loads of top-notch art throughout history has been made by individuals who were/are despicable people. If we start ignoring all the art made by unpleasant individuals, it's going to leave some pretty major gaps in the canon of many art forms. So in theory, I'm fully in favour of keeping the art separate from the artist. In practice, I agree that it's not that easy - in fact there are quite a few bands/musicians whose work I used to love that I now find it much harder to enjoy, after having become aware of their personal flaws. Difficult one, innit?

The thing about DI boxes is that it depends on what you're trying to achieve: do you want to preserve the sound of your bass with maximum fidelity, or do you want to mess with it in some way that you hope to find subjectively pleasing? If you're trying to maintain fidelity, the answer is easy: you want an active DI box, because electronics that do this are cheap and reliable; nothing is really going to do this any better than the £35 Orchid DI box mentioned by various people above. If you want the sound to be altered in some way, then all bets are off, because who knows what changes you might deem acceptable or desirable? Any passive DI box, no matter how high quality, with a passive bass plugged directly into it, is going to alter the frequency response quite radically, because their input inpedance is always too low to match the bass's magnetic pickups properly. This doesn't apply with active basses, because the pickups are buffered by the electronics in the bass, so then you might well notice that the more expensive passive DIs have lower distortion and greater fidelity than cheaper ones. But then if high fidelity is what you're after, you should probably just get an active DI anyway. So at this point, it's really all going to be a bit hit-and-miss which passive DI, cheap or expensive, will do things to the sound that you happen to like. In which case you might as well try out some cheap ones (as long as they're sufficiently well-constructed to not fall apart, which most seem to be...) since they're probably just as likely to make the particular sound you want as a more expensive one is...

You want cheap? Here's cheap: [url="https://www.thomann.de/gb/millenium_die_dibox_passiv.htm"]https://www.thomann.de/gb/millenium_die_dibox_passiv.htm[/url] Give it a try - what's to lose? It might be perfect for your needs! Why do you particularly want a passive one? My own choice would be another vote for the Orchid Electronics ones recommended by sk8, but they are active, as you noted.

Hmm, a late surge in popularity for the 'leave it alone' option! It's great to get these differing opinions to weigh up!

Ah, interesting to have an alternative viewpoint Ghost, thanks for that! Didn't know that the original Promethean had a traditional driver while its extension cab had a neo - that seems quite strange! It's okay man, we're among friends here, we can use the 'h' word! Pretty certain from the manufacturer's part number that the driver in my H-B is the Elder Audio / Beta Three one...

Hi Balcro That's all extremely useful info - thanks very much indeed for your help with this! I'm leaning towards getting the Celestion driver - if this happens I'll let you know how the results pan out! Thanks again, Paul

Having now had another look at WinISD using the correct cab dimensions , the existing tuning of the cab seems a bit more sensible and less lumpy...? It also seems to emphasise the differences between the response curves of the Deltalite 2510 and the Celestion NTR10-2520D - the Deltalite seems to be a bit louder from ~110Hz to ~200Hz, while the Celestion seems to be a bit louder from ~110 Hz down to ~70Hz ...? This tends to make me think the Celestion might be the better bet - would you agree?

Hi Balcro The dimensions on the diagram are my own measurements, so I have to admit an error: the port height, marked as 37mm, is in fact 25mm. The other figures on the diagram are correct. Updated diagram attached! [attachment=256627:hb-cab.jpg] The dimensions in my original post were copied from a post on TalkBass - I have now realised that that post referred to the original Ibanez Promethean combo, which is very closely related to my HB/RedSub/Beta-Aivin combo but does have different cabinet dimensions. Apologies for my stupidity! Paul

Hi Balcro I did have a play with the cab tuning a bit in WinISD, without having much of a clue what I was doing! As far as I could see, the existing dimensions gave it a tuning of about 99 Hz, and a lump in the bass at about 130 Hz. The way the port and its shelf are arranged is a bit difficult to describe, so here's a quick 'n' dirty diagram: [attachment=256533:hb-cab.jpg] I noticed that lowering the tuning of the cab to about 65 Hz gave a smoother response and extended the bass range a bit. However, this would seem to involve lengthening the port to 415mm, which seems a bit tricky given the size/shape of the cab! I thought of maybe extending the port shelf to the back edge of the cab - this would make the port about 205mm long and, I think, reduce the tuning to about 85 Hz. Is this the kind of thing you're suggesting? It looks from the WinISD graphs as though either the Deltalite or the Celestion driver would be a big improvement over the stock driver - I'm really just trying to confirm that swapping the driver would be a worthwhile endeavour! Thanks again for spending your time on this! cheers, Paul

Thanks, Bill. I appreciate that such a tiny box is never going to produce ground-shaking bass, but this cheap little combo has been so good, I think it may be worth spending a bit of extra money to get the best performance I can from it.

Thanks very much for the replies! I took some measurements from my own box today, and calculated the internal volume as about 17.9 litres, after accounting for driver displacement and port volumes. I also had a play with WinISD (though I freely admit I don't really know what I'm doing with it), and it appeared to me that either the Eminence Deltalite II 2510 or the Celestion NTR10-2520D would be a huge improvement over the original driver in terms of maximum output before hitting the driver's excursion limit. Just trying to understand this stuff better: Balcro: what leads you to suggest that the Eminence 2510 wouldn't be happy in such a small box? The Eminence spec sheet seems to recommend vented boxes from 17 to 40 litres...? Bill: what's causing you to favour the 2510 over the Celestion? Also (veering far out of my comfort zone!) why does a Qes of 0.21 rule out the 3010MB as a bass driver? And do any other suitable alternative drivers spring to mind?!

I've got a Harley-Benton BA5110C - a 1x10" 250W/500W combo which was also available branded as Red Sub and Beta-Aivin, and is also (very!) closely related to the original version of the Ibanez Promethean, as extensively discussed [url="http://basschat.co.uk/topic/168416-another-promethean-clone/"]in this old thread[/url]. I'm interested in upgrading its [url="http://www.elderaudio.com/products/Loudspeakers/LowMiddle/2009/10LB075-U.html"]original driver[/url], with several possible goals in mind: 1) reducing weight by using a Neodymium speaker 2) extending headroom by using a driver with a higher maximum output 3) possibly improving the bass response of the combo (though I understand that this is limited by its tiny cabinet) In the original thread linked above, there was some discussion of such an upgrade, and [url="http://basschat.co.uk/user/21427-straightsix/"]StraightSix[/url] said he'd used a [url="https://celestion.com/product/72/ntr102520d/"]Celestion NTR10-2520D[/url] for this, with good results. The [url="http://www.eminence.com/speakers/speaker-detail/?model=DeltaliteII_2510"]Eminence DeltaLite II 2510[/url] was also mentioned as a possibility. This was way back in 2014 though, and things seem to move quite quickly in the world of drivers - price changes, new models etc. So what I'm looking for is some advice from any passing speaker experts as to whether this Celestion might still be a good choice ([url="https://goo.gl/a2fYYp"]currently £139 from Lean[/url]) , or whether there might now be better options - eg [url="http://www.eminence.com/speakers/speaker-detail/?model=Kappalite_3010MB"]Eminence Kappalite 3010MB[/url] ([url="http://www.lean-business.co.uk/eshop/eminence-kappalite-3010mb-10-400w-8-ohm-neo-loudspeaker-driver-p-2162.html"]a bit pricey at £170[/url]) ? If it's helpful, here's the dimensions of the cab section of the combo, copied from a [url="http://www.talkbass.com/forum/f15/ibanez-promethean-p5110-speaker-upgrade-874880/"]thread that StraightSix started at The Other Place[/url]... [indent=1] The internal cab dimensions are: 285mm high 302m wide 213mm deep There is a slot port at the front 302mm X 28mm and the port shelf runs from the front of the cab and leaves a 100mm air gap between the rear shelf edge and the rear cabinet panel.[/indent] Thanks in advance for any suggestions! Paul