JTUK Posted October 26, 2015 Share Posted October 26, 2015 For me, it goes deeper than that. My basic set-up is pretty neutral on the amp... I'm not much bothered about what that actual means frequency-wise as I know which ones are helpful and which ones aren't... But I've also put an awful lot of time into my playing so solo parts sound nice..to my ears. so my sound doesn't need a lot of EQ'ing...and certainly not fighting it. It doesn't need compression and it doesn't need much set-up. I can go from home set-up to gig and all that changes is the master. I don't get problems from the room..can't recall the last time that happened and I don't get directions from sound men...so it is not extreme for them and they don't need a lot of work on it....if they have balanced their P.A and know what they are doing. I'd say the end sound is the same as the acoustic sound or ball park..but louder and with one or two bits that are peakier.. I'd start from a clean position in regards to the initial signal and dull it down to suit. You can't do it the other way round without running into all sorts of unwanted fights and I'd suggest the latter is why a a lot of guys have never-ending problems with sound. Quote Link to comment Share on other sites More sharing options...
paulnb57 Posted October 26, 2015 Share Posted October 26, 2015 Looking forward to seeing construction details of the 12 and the 15......great stuff chaps! Quote Link to comment Share on other sites More sharing options...
Thunderpaws Posted October 26, 2015 Share Posted October 26, 2015 Well done for getting these finished and having photographic proof. You must be very pleased with yourself. Looking forward to getting stuck in to mine. It's inspiring to see the finished product and to hear it too. Quote Link to comment Share on other sites More sharing options...
stevie Posted October 28, 2015 Share Posted October 28, 2015 (edited) I would have posted this a lot earlier but I hit a snag. When I started measuring one of the cabs I have here, it didn’t measure the same as the one I had had here a few weeks ago. I spent hours trying to figure out what was going on. I even started recalibrating all my measuring gear. Eventually, I pulled out a speaker that I know measures flat and tried it: it was flat. The penny dropped and I put the second cab on the bench and measured it. There was a problem with one of the Beymas. This makes a bit of a mockery of our comparison test at the Bash. This is how they measured. I’d say one of those was definitely not to spec. The red one is the good one, by the way. More to follow shortly. Edited December 15, 2018 by stevie Quote Link to comment Share on other sites More sharing options...
Beer of the Bass Posted October 28, 2015 Share Posted October 28, 2015 Just to help square things up with what we're hearing on the recordings, can you remember which cab had the healthy one? Quote Link to comment Share on other sites More sharing options...
Chienmortbb Posted October 28, 2015 Share Posted October 28, 2015 (edited) That exaggerated peak at 2.1KHz and is in the "presences" area making that driver a contender for a guitar speaker. The 3KHz peak added to the 2.1 KHz peak may explain the exaggerated mids. Edited October 28, 2015 by Chienmortbb Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted October 29, 2015 Author Share Posted October 29, 2015 Hi Stevie, before we get carried away these traces aren't so different. The troughs at 1.1and 3kHz and peaks at 2.1,3,0,3.3 and 4.5khz pretty much align and aren't that big. only the peak at 700hz is above +/- 1dB. Did you try swapping the speakers between cabs? Is it possible the cabs are contributing to the differences in the plots? do we know it is solely down to the drive units? I'm assuming this is the small signal response measured at about 1m? I'm quite willing to believe that either of the drive units does not meet it's spec. or has been damaged during the build process but I'm not completely convinced about this either. What do you think? Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 [quote name='Beer of the Bass' timestamp='1446056120' post='2896579'] Just to help square things up with what we're hearing on the recordings, can you remember which cab had the healthy one? [/quote] Yes, the cabinet (on the left, for those who were there) made up in 1/2" ply had the good driver in. Most people (including me) seem to prefer this one from the recordings. On the other hand, there was near unanimous agreement at the Bash that the other one sounded better. The only explanation I have for this (and I wouldn't bet my life on it) is that we were all listening well off axis at the Bash, i.e. we were all quite close to the cabs. So the peaks would have been much lower in level than in the recordings, which were made directly in front of the cabs. There was also a substantial amount of "panel talk" coming from the 1/2" cab that the close micing would not necessarliy have picked up. Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 Phil, a peak like that followed by a dip is invariably a resonance. Located just under 1kHz as it is, I'm pretty sure it is a surround resonance. Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 (edited) This is the anechoic frequency response of the cab - in other words, the response of the cabinet excluding the room reflections. Because of the size of my measuring space, it's only valid down to 300Hz. To measure lower than that, I need to go outside, measure the LF response, and then stitch that to my 300Hz+ measurement. Unless you have an anchoic chamber, everyone uses this method, or a variant of it, to get a full range curve. With the weather as it is, this is not going to happen today. However, I did carry out an RTA measurement with the cab on the floor (how it will actually be used), which tells us what we need to know. Edited December 15, 2018 by stevie Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 (edited) Here's the impedance curve of the slotted port version. The cab is tuned to about 46Hz, a bit lower than the first tube-ported version. Edited December 15, 2018 by stevie Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 (edited) Although this is only at a few watts, the distortion measurement is still very impressive. Edited December 15, 2018 by stevie Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 (edited) Just a final note. I've modelled what you'll get with a variety of other popular bass guitar drivers in this cabinet: These are: Red: Beyma SM212 Orange: Kappalite 30120HO Yellow: Faital PR300 Blue: Celestion BN12 300X Green Eminence Beta 12a Apart from the Eminence, which exhibits mild peaking at 100Hz, the others are very close below 200Hz in this cabinet. Naturally, there will be differences in the midrange and in matters such as power handling. As I have an Eminence Beta 12a here, I measured its response in this very same cab. I have to say, it looks rather good. Edited October 29, 2015 by stevie Quote Link to comment Share on other sites More sharing options...
Beer of the Bass Posted October 29, 2015 Share Posted October 29, 2015 (edited) [quote name='stevie' timestamp='1446119264' post='2897011'] As I have an Eminence Beta 12a here, I measured its response in this very same cab. I have to say, it looks rather good. [/quote] Interesting that you should bring up the Beta 12a, as I picked one up recently that was going very cheaply used. When I get around to it I intend to try it in something close to the cab design being developed here and see it sounds. I have a GK MB200 at the moment and intend to mess around with low powered valve amps at some point in the future, so it may be that the Beta will do a decent job for my needs (and if not, I'm not out by much if I try the Beyma later). Certainly people seem to enjoy them in those TKS cabs, assuming that's what they use. Edited October 29, 2015 by Beer of the Bass Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 (edited) Sounds like a plan. I've often used the Beta 12 in PA cabs before because it handles voice very well, but I've no direct experience of it with bass guitar. I wouldn't really expect it to come close to the Beyma - but it is quite a bit cheaper. Edited October 29, 2015 by stevie Quote Link to comment Share on other sites More sharing options...
Jimrs2k2 Posted October 29, 2015 Share Posted October 29, 2015 Steve, ha I knew my ears weren't that bad at the bash, I tend not to get too hung up on the mids issue as some others maybe. As with the markbass shoot out as the southwest bash I found that the original one would be better for some home practice and solo work, but in a band context the one with the tweeter swap would be the one I would take, the more prominent mid and high end would sit better in the band mix and stop the bassist becoming a mime artist lol. I personally preferred the 1/2 " cab on the day, but if the 3/4 ply ones driver was playing up the it's a draw as far as I could tell. Jim. Quote Link to comment Share on other sites More sharing options...
stevie Posted October 29, 2015 Share Posted October 29, 2015 Indeed! You were in fact the one who made me write "near unanimous". It's so easy to be bamboozled by what you hear - measurements are more reliable most of the time. Except that I'm still hearing prominent mids from this cab, which the measurements are not showing. Pulling back around the 500Hz mark takes out the "boing" overtone that I've also heard with some other 12" cabs. I was going to calculate a filter to put a notch in the frequency response, but as nobody else seems particularly bothered, I'm going to leave it alone. Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted October 29, 2015 Share Posted October 29, 2015 [quote name='stevie' timestamp='1446144144' post='2897341'] Indeed! You were in fact the one who made me write "near unanimous". It's so easy to be bamboozled by what you hear - measurements are more reliable most of the time. Except that I'm still hearing prominent mids from this cab, which the measurements are not showing. Pulling back around the 500Hz mark takes out the "boing" overtone that I've also heard with some other 12" cabs. I was going to calculate a filter to put a notch in the frequency response, but as nobody else seems particularly bothered, I'm going to leave it alone. [/quote] have you got a commercial bass cab to hand that doesn't sound prominent mids? I wonder if you measured that and your cab side by side you would be able to see on the charts what the other cab was doing that made your build seem "middy" Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted October 30, 2015 Share Posted October 30, 2015 this might be interesting.... If you were making a well respected product that wanted to model a load of cabs with it you probably would get reasonably close to what they should sound like... so if someone then took the Zoom B3 (a nice sounding bit of kit) and measured the cab model responses... well they wouldn't be spot on but would possibly be a good comparison to what you've built! http://www.zinfanus.com/zoom_b3/cabinets/index.htm Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted October 30, 2015 Author Share Posted October 30, 2015 [quote name='Beer of the Bass' timestamp='1446123798' post='2897071'] Interesting that you should bring up the Beta 12a, as I picked one up recently that was going very cheaply used. When I get around to it I intend to try it in something close to the cab design being developed here and see it sounds. I have a GK MB200 at the moment and intend to mess around with low powered valve amps at some point in the future, so it may be that the Beta will do a decent job for my needs (and if not, I'm not out by much if I try the Beyma later). Certainly people seem to enjoy them in those TKS cabs, assuming that's what they use. [/quote] If you go back to the beginning of this very long thread you'll find that we modelled the Eminence Beta (and the Kappalite 3012HO) as alternatives to the Beyma. They both modelled very well, the only reason for choosing the Beyma over the Beta was the much better excursion of the Beyma meaning it would handle deep bass at high power better than the Beta. If you could put up with some limitations on the deep bass then the Beta would be an excellent drop in replacement for the cab with no mods needed. I haven't gigged this cab with the Beta The Kappalite HO would be a great speaker to put in but would cost a lot more than the Beyma with the main advantage being weight saving. In the 12mm cab this would give you a truly lightweight option around about 12kg. We haven't tried the HO as yet but I see no reason why it wouldn't work as a great cab. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted October 30, 2015 Author Share Posted October 30, 2015 [quote name='LukeFRC' timestamp='1446163191' post='2897493'] have you got a commercial bass cab to hand that doesn't sound prominent mids? I wonder if you measured that and your cab side by side you would be able to see on the charts what the other cab was doing that made your build seem "middy" [/quote] We are running this on a shoestring budget and this is something Stevie and I have privately talked about doing, but can't afford. It would need the goodwill of some of the Southwest bass players to lend us their cabs for measurement. My theory is that most of the commercial cabs I've heard have a 'smiley face' response but with little deep bass. This cab has a broadly neutral response so someone listening and expecting the smiley face will perceive the difference as a prominent mid, compared with the mid shy cabs they are more used to. Unless we run measurements though we are just guessing, though hopefully intelligently. Quote Link to comment Share on other sites More sharing options...
stevie Posted October 30, 2015 Share Posted October 30, 2015 [quote name='LukeFRC' timestamp='1446163191' post='2897493'] have you got a commercial bass cab to hand that doesn't sound prominent mids? I wonder if you measured that and your cab side by side you would be able to see on the charts what the other cab was doing that made your build seem "middy" [/quote] I'm afraid not, Luke. I've only got my own 15" - but that also measures flat and doesn't have the bark of this 12. So I'm a bit flummoxed. Having a well-thought-of 12" cabinet for comparison purposes would have made life a lot easier. Those simulations you linked to mostly show speakers with a falling response towards the midrange. The Basschat 12 doesn't do that, but it's easy enough to produce that kind of sound balance with your preamp. When I pull the 500Hz area down with my amp, I get 'my' sound (not a Trace smiley-face sound - I like plenty of mids). So I don't want to over-emphasise this. Quote Link to comment Share on other sites More sharing options...
Guest bassman7755 Posted November 2, 2015 Share Posted November 2, 2015 [quote name='stevie' timestamp='1446200124' post='2897617'] I'm a bit flummoxed. [/quote] I notice there is a quite a sharp distortion peak around 500hz, maybe thats got something to do with it. Quote Link to comment Share on other sites More sharing options...
stevie Posted November 3, 2015 Share Posted November 3, 2015 Yes, well spotted, although 1% is not a lot and it is a very narrow peak. I wouldn't expect it to be audible. Having listened to some similar cabs on the web, I'm coming to the conclusion that a flat frequency response cab can benefit from some tonal adjustment to get the particular sound you're looking for. Also, quite a lot of cabs seem to 'bake in' a boost at 100Hz, which has the subjective effect of making the lower mids less prominent. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted November 3, 2015 Author Share Posted November 3, 2015 Without any measurements to back this up it is fairly obvious that a lot of commercial cabs have a 'smiley face' engineered in. A typical commercial 12" cab has an Eminence driver, often a 'special' built into a small cab. I'm talking mid-range price here. If you look at the Eminence Beta http://www.eminence.com/pdf/Beta_12A-2.pdf it has a marked (3dB) peak in on axis response between 1 and 3kHz . This is typical of a range of commercial drivers. Put it into a small box (typically 1.25-1.75 cu ft, sorry Eminence use imperial units) and you'll get a roughly 3dB peak between 100 and 200Hz. So the midrange gap between 200-1000Hz is 3dB down from the rest of the speakers response in a 'normal' speaker. If you aren't used to anything else then a speaker without the same midrange dropout will sound middle biased. Which is 'wrong'? Well neither of them, people like the sound of a midrange suckout and if it isn't inherently built into the cabs response dial it in with eq, or with their bridge/neck pickup settings. Other people want to start with a flat response that they are then in charge of. That's what people asked for when we started this project and I think we met the design brief you came up with. I'm not being defensive I hope. The problem with a self build is you don't know what it will sound like until you build it and most people can't 'hear' a speaker from a graph and a set of figures. I want people to have a good idea of what they'll get. I think it's fair to say this will be a very open, clean sounding speaker with a bit more deep bass than most speakers but without the artificial warmth of many commercial units. It'll go very loud without stressing, respond well to eq tweaks and yes, you'll notice some midrange that might not be there in your old speakers. At some stage I'd love to run some measurements on commercial speakers and I'm planning on coming up with an 'old school' speaker at some stage. Quote Link to comment Share on other sites More sharing options...
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