Phil Starr

[quote name='Chienmortbb' timestamp='1491380414' post='3272501'] The think is there is no right or wrong, it is a personal thing. Phil's idea of a smaller cab creating a low mid peak is as valid as the "HiFi" cab. The choice is yours. [/quote] There's no disagreement between us all about this, before the Mk1 I had the Beyma's in a couple of PA cabs with some really meaty horns crossed over at 1600Hz. They gave me the best sound I've ever had with a bass and that's what inspired me to try them with the horns disconnected, and ultimately led to the design of the Mk1. The reason for wanting to do a small cab is really only because I can't stop fiddling with designs to see where they can be pushed. If it is successful we'll have the basis for a lightweight version giving home builders another option, if it isn't successful then you'll know not to go there.

[quote name='stevie' timestamp='1491339089' post='3272314'] With a first order cap you'll be somewhere in the ballpark and it will sort of work. Once you add a coil to the circuit, the results could be disastrous unless you know what you're doing. I really wouldn't. In fact, using a crossover calculator is doomed to failure because they work on the assumption that you have a flat impedance curve on all your drivers, that they have a flat and extended frequency response and are time aligned. None of which is ever the case. [/quote] We'll have to disagree here I think. First of all we are talking about an instrument speaker. Michael might not get a flat frequency response, if that is what he is aiming for, but it could still sound quite good, and be better than his single driver. By going for a 2-way crossover you are trading some anomalies which you mention for the genuine problem that with no roll off of the bass you will have two drivers that will be radiating the same frequencies at different levels and from different points creating all sorts of comb filtering and other reinforcement and phase problems. Most of my experience in designing crossovers has been in hi fi cabs, where if anything sound is more critical. I've never really been a fan of complex crossovers, adding components in the form of notch filters and so on never exactly match the frequency anomalies of the drivers and introduce problems of their own. My own preference in listening tests has always been for 2nd order crossovers with the minimum of components, though I only ever use drivers that are more or less flat in the octave on the far side of the crossover point. If Michael chooses the drivers wisely a 2 way crossover might work well. So might a single capacitor high pass filter. Passive crossovers are never perfect but I wouldn't want to put Michael off from trying, just as long as he understands he won't know what his design will sound like until it is built.

[quote name='Gottastopbuyinggear' timestamp='1491309555' post='3272002'] Not the sound you want - now he tells us! I'm still relatively inexperienced with all this (from a user point of view) so I'm quite keen to do a bit of experimentation to see how a different speaker would sound in the real world. I need to revisit the modelling to check but I did look at putting a Beta 12 in the Mk1 cab (partly to free up a Beyma for a Mk 2 build, and partly just for curiosity) which I think predicted a similar bump of 2 or 3dB around 110 Hz or so. Of course the Beta 12 does have a pretty big hump in the high mids, so overall I guess the sound would be substantially different. [/quote] Sorry It's a long time ago now but the design was specced by people on here, who wanted a neutral/flat response and lots of lovely bass in a compact cab, it wouldn't have been my choice but it does mean you can eq in the response you want, as I have been doing. I've had some mild teasing because what I've ended up with is pretty much the response of a Beta 12 in a small box drawn permanently onto my graphic. I'm not a sophisticated bass player Stevie is taking the next logical step, adding the horn and driver and tweaking the crossover means the response is flat all the way up as far as a bass is concerned and you can pretty much dial in what you want, all with less distortion and more controlled dispersion of the sound

[quote name='The Shrek' timestamp='1491233409' post='3271426'] Thanks Stevie. Guys I hope I am not being forward in asking this question. I would gladly pay upfront for the service if there are any of you basschat guys who would be prepared to build a proper crossover for my project. Just advise me on what speakers to buy to match the appropriate crossover build. I am in Northern Ireland so I will gladly pay for any excessive post and packing and any other costs. Michael [/quote] Hi Michael, though it won't be fully optimised for your particular drivers you can always use a bog standard crossover circuit instead of just a capacitor to protect the 5" unit from the bass (and most of the power). The simplest would be a 1st order crossover to gradually remove the higher frequencies from the bass unit but a better way would be a 2nd order design Which has a quicker cut off for both speakers at the crossover point. You can get the basic calculations done here https://www.diyaudioandvideo.com/Calculator/SpeakerCrossover/ Go for the Butterworth for 1st order or the Linkwitz-Riley for the 2nd order. It'll only work if your speakers are more or less the same sensitivity.

Yes if you really wanted a lighter Trace it might be better to mount the Trace Drivers in a lighter cab. MDF has great sonic properties (mass, youngs modulus, uniformity and self damping) but isn't great for a portable cab. It's heavy, goes soft and distorts if it gets wet, and isn't as tough as ply. With the same drivers in the same shaped cab it'd pretty much keep the original sound give or take a panel resonance.

Watts are only half the story (keeping the story simple) the other half is the efficiency of the the speakers. The sensitivity tell you how many dB's you'll get with one watt and then you can work out how many you'll get with one particular amp. Let's say you have a speaker that gives you 94dB for 1W, Doubling the power gives you an extra 3dB and ten times the power gives you 10dB extra. 100W will give you 114db through this speaker Now swap the speaker for something efficient, 100db for each watt, this will give you the same 20dB extra with a 100W amp or 120dB. To make the first speaker as loud you need two lots of 3db more power which means four times as much or 400W. Now 120dB happens to be about the sound level needed to work with an average drummer, and so long as your drummer is average that's the level to aim at, roughly. A bit more detail if you want https://www.ultimate-guitar.com/lessons/the_guide_to/making_it_loud.html

!4 kg is good, my originals came out at around that without the horn and crossover, though my bracing internally was a bit agricultural (rushed for the last bass bash) and I used Baltic birch rather than poplar. Yes I'm looking at doing a 40litre version, possibly even smaller as I might do some prototyping with a bit of spare ply. Basically I find I always end up dialling in a hump at 100Hz and rolling off below 40 anyway, the response you'd get in an over small cab. That's fine with my Harke amp with a graphic but is proving harder with my Mark Bass amp. I'm wondering why I'm carrying extra wood to not quite get the sound I want. I'm also getting more interested in the pschoacoustics side of things, what actually makes up perceived bassiness, punch and, dare I say it h**t. With Stevie currently chasing FRFR cabs I might look at voicing in cabs. If it goes to plan then I'm going to have a go at a lighter cab with better bracing first (Stevie did a much better job than I did of damping the panel resonances), I may even look at other drivers if I'm feeling flush.

[quote name='skidder652003' timestamp='1491237851' post='3271469'] Now Im confused, those 300 watts are tube watts and a hell of a lot louder than any solid state amp Ive had (up to 1400 watt power amp. 800 watt SWR etc) but thats another thread! [/quote] It's simple enough Steve, you'll be pushing those valves into distortion and loving the sound. Your old solid state amps would sound really horrible pushed so hard so you turned them down to stop the distortion. You're pushing the valve amp harder is all, so the average power may be higher even if the peaks are not as big. I've heard your band remember

using a line source like the HK's can be good in a church or any echoey building. The problem with announcements in stations for example is down to poor control of sound direction with lots of confusing echoes each with a different time delay. They radiate as a big flat fan getting wider as you get further back but it might be down to a matter of trial and error mounting them to get the most audience coverage with the least echo. The usual method is to take advantage of the fact that sound levels drop off as you get further back from the speaker. Mounting them high and angled down gives you better coverage, pointing them at the middle of the intended audience rather than the people at the front helps. The sound loss of not being directly in line at the front is compensated for by being so close to the speakers. Without seeing the building of course it's not possible to be specific. Remember the RCF's or any other horn based speaker is going to be directional too. You can probably find the dispersion angles for the horns for most PA speakers (the RCF is 90x70 which is quite wide). Often they may be described as long, short or medium throw. If you can sketch out a scale drawing of the building it should be possible to find out what the ideal pattern would be and find something to match. The other trick is to have two speakers, a short throw (wide dispersion) to cover the front seats and a long throw pointing at the rear seats, though this may be unnecessarily complex and expensive. I hope this is reasonably clear and helps to give you some things to think about when choosing.

[quote name='Chienmortbb' timestamp='1490004174' post='3261317'] I am not sure of the model but the Mackie Thump 16s we have been using for open mic recently were not good (post RCF?). These were replaced with a pair of Alto that were great for vocals. However at another open mic night we used a Blue Acoustic M2 system (think Bose broomsticks with proper speakers on top) Without doubt the best portable system I have ever played through. [url="http://blue-acoustic.com/wp-content/uploads/2017/02/M2-System-Data-2017.pdf"]http://blue-acoustic...m-Data-2017.pdf[/url] [/quote] Hi John, the Thumps are Mackie's cheap and cheerful versions of a PA speaker, my experience is that they don't sound any worse than other cheap and cheerful speakers and I've heard acoustic acts sounding OK through them but you can't turn them up too loud before the cheap bass drivers overload, I suspect they don't have great Xmax. Efficiency isn't great either so the temptation is to push them too hard. I do know of bands using them successfully as floor monitors where feedback limits the power you can use anyway.

[quote name='owen' timestamp='1491138537' post='3270742'] Sorry to derail the thread slightly, but while we have PA bods attention can I ask another question? I run the PA at church (qumix 32 + HK audio Elements system). The Elements system suits what we need just fine for downstairs but the balcony is raked seating and the elements have a super tight dispersion. When you are sitting in the line of fire then it is all good, but if you are higher up the tiers then the detail gets lost. I am thinking of putting in some standard plastic boxes for upstairs with a broader hf dispersion. They do not need to be beefy because the HK subs will do the heavy lifting and I presume that I can do an HPF and a slight delay on seperate outs on the qumix (cos it does everything else). Can anyone suggest a suitable cab? [/quote]You don't give details of the size of the space or a budget. EBS freak is probably more up to date than I am but the obvious solution is to get further E435 Elements tops and as you suggest run them off the appropriate delay. If not then just go for one the smaller plastic boxes the RCF 308 suggests itself [url="http://www.rcf.it/en_US/products/pro-speaker-systems/art-7-series/art-708-a-mk-ii"]http://www.rcf.it/en...art-708-a-mk-ii[/url]

Just right clicked on the blank space and it comes up with Movie not loaded about Adobe Flash player 22.0.0.209... I'm wondering if this is to do with Chrome no longer being supported in XP? If so anyone know of a simple fix?

No, doesn't display for me. Could it be something to do with my ancient XP computer?

Thanks Mike for all the hard work, really well organised and as someone has already said very civilised. The food was really excellent too, many thanks to your family and friends for doing that for us.

Tuff cab seems OK with water based finishes. However I guess any other finish will act as a barrier between it and the woodand might affect the way it bonds, meaning it may chip easier later. I've had no problems so far though.

I've noticed lot's of blank spaces where You tube should be displayed, The ordinary links work but not the ones where you can see the video on the post. Any ideas why this might be happening?

It's popped up a few times for me too, not for about ten days though.

The same thing still applies I'm afraid. It will sound like a Trace amp with a modern cab in all probability, on the plus side it will look like an all Trace stack.

I use a Hartke Kickback 10. The old 120W one, there's a new one out but you will have to pay too much for those. You can pick the model I have up for about £100. It's got a typical Harke tone but it's a proper grown up bass guitar sound and can be quite revealing which is what you need for practice. I also use it for rehearsals and open mic nights so it goes fairly loud and I have done small gigs with it but it struggles if the drums get really loud. A mate who heard mine went out and got a Kickback 12 which sounds fairly similar with a bit more bottom. Generally speaking I'd avoid the 50-70W jobbies, without having heard all of them (so there may be a gem in there) they seem to be engineered to match a price point rather than achieving a good sound. Too loud for home practice not enough for gigging and not enough spent on the speakers so they sound bad. If you have space then go for some of the older combo's or even a separate stack. The old heavy stuff is really cheap as we all turn to stuff we can actually lift. If your's is sitting in a corner weight won't matter and the big old heavy stuff sounds lovely. The old Peavey stuff with Black Widow speakers is well worth looking for if you get it for a decent price. Alternatively practice through headphones, studio quality sound without annoying the neighbours. Zoom B1ON will let you mix in with recorded music from your phone, has a tuner and drum machine and allows you to emulate a whole series of amps and speakers for around £50

PMT are great as they are one of the few places you can get to try out a range of cabs. I do this the same way I audition hi-fi speakers, by taking an iPod loaded with 2 or three recordings I know really well with well recorded vocals and a good range of instruments to cover the frequency range. Shops get a bit twitchy if you take in recordings of test tones Anyway after my last audition of 12's at PMT I decided the Yamaha DXR's, JBL EV were all good, and like others I'm a fan of the Yamaha reliability/build quality but that the RCF's are a class above all these in terms of sound quality, especially the ones with the bigger horn drivers. I found a faint but noticeable veiling of vocals in the DXR's, especially female vocals, which were the best of the rest. There was just so much more detail from the RCF 312's and the better one, now replaced by a new model was a really smooth performer. Out in the world of gigging bands the people who use QSC seem to get a really good sound, so I'd try and get to listen to them too if you can. All of these speakers are terrific BTW and the limiting factor is going to be more about how you use them but for sheer sound quality I think RCF are currently the ones to beat.

My wife generally comes to see the bands I'm in a couple of times a year. The sets don't evolve that quickly and she's not a live music fan generally so that's pretty supportive IMO. Generally she comes along when we have friends visiting, by the time I've set up knocked down and maybe chatted with a few of the audience and the promoter there isn't much time with her at a gig. She'll make a point of coming to a first gig with a new band though.

The thing is that it isn't the box that really gives the cab it's voicing, it's the speakers. So, you could replace the speakers and if you matched them carefully and were prepared to fiddle with the tuning of the cab then it could work, it might even sound quite nice. What it won't do is sound like a Trace. You'd have the cosmetics of a Trace only, but the sound of something different.

[quote name='Chienmortbb' timestamp='1490482633' post='3265492'] No pressure then Phil? I am building the MK2 as fast as I can but illl health has put me behind schedule. I might have to bring a Wet Paint sign on Sunday. [/quote] I sent the MK 1 to the last one with the paint still wet, Graham probably has the marks on the back of his car still

I'm going to try to get along for a couple of hours. Unfortunately our band are rehearsing in the afternoon from 1.00pm but it's just the other side of Taunton so I should be fine for the first couple of hours. I'll bring along the original Basschat 12 in case someone is interested in building one. It'd be interesting to compare it with the tweetered Mk 2 versions. I could probably leave it with someone if people want to go on playing with it. GrahamT you know who you are

[quote name='stevie' timestamp='1490352944' post='3264493'] Not really a purchase, as BC member Alyctes generously gave me a Behringer BX4500H head; I just needed to replace the internal fan to get it working properly. Anyway, I took it to a two-hour rehearsal recently and kept switching over from my normal Tonehammer 500 to the Behringer - both set flat into a very transparent cab. I listened very carefully. There was *[i]no discernable difference[/i]*. How is that possible when the TH500 is considered to be the cream of the current amplifier crop and costs about £800 while the Behringer originally cost about £180 and can now be picked up for peanuts? This was a bit of a reality check. Definitely recommended for anyone on a budget. [/quote] Hi Stevie, if 'set flat' genuinely is flat then all amps should sound the almost the same unless you are running them at their limits. The distortion created by most amps nowadays is pretty minimal, you might be able to detect differences in an A to B test under ideal circumstances but even that is getting difficult. With a band playing around you any difference in sound with a bass ought to be down to how the preamp is voiced. Most bass amps don't sound very good with recorded music played in through the guitar jack so I assume for a lot of them there isn't a flat frequency response with all the controls at 12 o'clock. It would be interesting to see if these two do sound good with music and the controls set flat, and perhaps to compare them to a DI'd sound through the PA. Makes you think though, if the only difference is down to the tone controls then why spend so much on an amp.