Phil Starr

Hi Stew, I put this on the wrong thread. I'll try again in an hour or so and get back to you then.

posted in the wrong thread

Try the Peavey IPR 1600 it's light as any lightweight bass amp and has combi sockets on the inputs. Mine have been 100% reliable and from memory its about 400W RMS into 8ohms 1600 bridged.

Off to the gym now Baggy T shirt next time...

Now you know where my waistline in the video came from

Sorry I can't resist and it's probably not what you want to hear. Why Class AB? you probably think there is a 'digital' sound? Honestly you won't be able to hear a difference, all else being equal. Your bass amp is made of three parts, a pre amp that shapes the sound, the power amp stage that makes the watts and a power supply that... supplies the power for the amp. The two things that primarilydetermine the sound of the amp at high power are the pre amp shaping and whether the power supply is adequate for the job. I'm not telling you all amps are equal, just that the class of the power amp isn't the critical factor. You specify a compact, and I'm assuming lightweight amp. They only achieve this if they have a switch mode power supply. Anything with a big and heavy old style copper wire transformer is going to be big and heavy by definition. If you have a lightweight switch mode power supply then you might as well have an efficient switch mode amplifier. If there was a difference in heft (there I said it) between the old heavy amps and the new switch mode amps a lot of that is down to poorer power supplies than the more mature designs of the old class AB amps. There are later models of class D with decent supplies. I don't know of anything with an old heavy power supply and a class AB power amp but maybe someone else will come along with a suggestion. It doesn't matter, audition a range of amps, if the only ones that sound the way you want are heavyweights you'll have to suck up the job of carrying them but I think you should give the newer amps an audition. Just think, if you play a big venue your amp is just a stage monitor, the bass you hear at big concerts comes from the PA and that will certainly be Class D. You'll never get that big a sound with your bass stack. Actually I've just noticed you wanted to bypass the pre amp, why not just buy a PA amp, run it straight off whatever you are already using, your sound but louder. Cheaper than a bass amp with a pre amp you don't want to use anyway.

Many thanks to Mike and his family and friends who did all the hard work. I hope they enjoyed it because for the rest of us it was so much fun.

There are lots of plus points about going lightweight though. The HA3500 weighs more than my cabs and it's getting long in the tooth so needs the odd repair every now and then, it is very noisy with the graphic switched in and the fan is so noisy when you are playing at low levels. I still love it but it's not reliable enough for me to trust it at paying gigs. I did contemplate buying one new when they were on offer a while ago but the MB Tube is fine and 100% reliable.

Thanks guys, see you tomorrow.

I moved from the HA 3500 to the MB Tube. Whisper it quietly (if you can hear a whisper over the Harke fan) the Hartke sounds better.

Thanks Mike sorry about the late notice, some of you will have seen me promise this on another thread over in Amps and Speakers. The problem was we got booked for a gig and I didn't think I could make the bash, then our guitarist had a medical problem so we cancelled the gig at the last minute. I'm going to attempt a basic build of a 1x12 cab up to initial testing as a demo of how easy it is to construct your own speaker. What I'm after is a continuous video of the whole build. I can bring a tripod so the camera can just be set up to run or someone keen would be welcome to be more artistic if they prefer. I'm hoping to do the whole build inside an hour but I've never done this in front of anybody before so it'll be interesting to see how quickly it can be put together, I'll try and answer any questions as I go. I'd be really grateful if someone could help out for an hour. Phil

Hi, I have one of these, It was on a special offer when I bought it a few years back and I think I paid only about £30 more than the LM III was at the time, otherwise I'd have gone for the LM III. The valve preamp is very subtle in it's effect, you aren't going to get valvey overdrive but it does add warmth. In practice I have the valve up full and solid state turned right down so I guess it must be useful. I didn't realise it had phantom power ha ha, I just plug it in and go but I have used a mic to get some percussion through the cab and that works OK. I'm probably not the one to comment on tone, I just use it flat most of the time and only eq for room acoustics. For me the amp does what it says on the tin. I can go as loud as the drums without overload with a couple of 12's and it is completely reliable. The VPF filter is useful at home and you can dial in some nice tones fairly simply but in a live situation I just turn it off usually to get a bit more penetration for the bass. I can only say you should try it out and see if you like the way it sounds with your own gear.

I designed something similar to that cab back in 1970, before the days when we used Thiele Small and computers had their own rooms and used punched cards. There were many such designs with effectively a conical horn built on the back of the cab with the expectation that the efficiency of the horn would enhance the bass and make the cab 'long throw'. In those days speakers were generally limited to around 50W for a 15" speaker and amps were really expensive so we were mainly looking for high efficiency rather than fidelity. There was a lot of trial and error involved! I suspect there wasn't a lot of calculation involved in the RH115 and Win ISD wouldn't be able to calculate the effect of horn loading on the cab. In my 'design' I got lucky. I was working late when someone needed some speakers and the only things to hand were my half finished prototypes. I hadn't finished making the rear horn so I bodged a simple unfolded horn and sent them out, they sounded so good compared to a lot of the **** available at the time that I quit when I was ahead and sold a few to disco's quite successfully. Looking back I don't suppose they probably only worked as bass reflex speakers but people liked the horn look of them. Just enjoy your cab, it might be worth something someday, people like the old school sound and most of the drivers were long ago replaced with something with a bit more power handling, they could become collectors items.

I'm just a little concerned here. If the original tweeter is a piezo it isn't likely that it has a crossover or that if it does it will match a 'proper' horn driver. People seem to be implying that early Markbass models used a piezo and later ones a coil driven unit, which would have had some sort of crossover. You really need to check before you start swapping things around. Without some sort of crossover the bass will go through the replacement tweeter and destroy it as soon as you play at volume. Piezos have high impedance at low frequencies and so filter out bass by their nature, this saves the cost of a crossover and is one reason why they are so cheap. If it is a coil/magnet based compression driver and horn in your speaker then any replacement would need to match the spec of the old unit fairly well in terms of sensitivity, impedance and power handling at least. It looks like others have used the HT30 successfully so I'd copy that mod in your position, but check first.

Coincidence, I went on to put up a thread about going naked, and here one is We gigged on Sunday with my occasional duo. Beer festival where we were on last, the previous guy was still playing when we arrived and the place was packed, Little time to set up and minimal soundcheck and we were stuck in an alcove next to the smokers escape route on one side and the gents on the other. Tight enough space that people kept knocking into my bass which didn't enhance my timing. On top of that the acoustics were awful and we couldn't really hear the backline. Three songs in the landlady had a complaint about noise and asked us to turn down so we lost whatever balance I'd achieved earlier. We survived and the audience seemed to enjoy themselves but grrr.... So Monday was spent setting up with no backline, I thought my mate would spit his dummy out about his guitar 'sound' but he'd found that gig as stressful as I did and was happy to give it a go. I like to keep things simple live, so we went for using the same monitor mix as the audience mix. To be honest it was total bliss. The bass sounded great through the monitors, acoustic guitar was the best sound ever and thanks to a G1XON so did the few electric guitar parts. BV's were so much easier to judge when you know what the audience are hearing too, I can sit in just under the lead vocal with confidence now. With the mixer sitting between the monitors we can fix everything immediately and turning volume up/down needs just one twist of a knob. So what gave the great bass sound? Bass straight into the mixer and two Behringer 1320D floor monitors.

I started out with one of these along with a matching 2x15. I don't think I've ever had a better sound but the 2x15 was a bit bulky Not actually that heavy though. The eq is as good as it gets. They are certainly very usable and plenty loud enough. I had to replace some of the power supply capacitors though. You'll often get problems with them on older amps whatever the brand and amps sitting around doesn't help. the good news is that if these do need repair they are an easy job to work on. They don't fetch much used, I'd be expecting around £100 in average condition, maybe £120.

Hi Bill looks like our posts crossed. there's no doubts about the effects you mention or that the Q of the cab is changed by filling the airspace but I've seen all sorts of claims for 'damping' from the use of high density materials to kill panel resonances through placement to kill standing waves within the cab and so on and so on. We'll both be aware of some of the claims and counter claims about damping materials. Without decent software and test gear it's not an easy thing to be able to say put x amount of stuffing in this part of your cab. Some of the treatments I've seen in commercial cabs leaves the impression that they've done it just so it looks right. Kevin, my advice is to find an old polyester filled duvet and experiment with the material in that, Dacron is just the brand name. using the material to hand lets you do a lot of experimenting at little or no cost.

Hi Kevin, as a second opinion I'd say that stuffing an enclosure is a complex subject, I still haven't seen a complete mathematical model for this and adding damping materials is done in differing ways in different cabs to achieve a variety of outcomes. Dacron is a very light material and when thin nearly acoustically transparent. There's no doubt that it affects the response of the cab and generally flattens the response by damping resonances but the effects aren't huge unless you achieve reasonably high densities, you'd probably want at least a kilo of stuffing in your cab, keep it away from the ports. As to whether it will improve the sound of your cab I suggest you try it and stick with whatever treatment gives the sound you prefer. The bracing does look a bit haphazard though.

If you look at Bill's graphs it's fairly easy to see what is happening. Stuffing the ports to block their output cuts the deep bass by 3dB roughly. Cutting the bass makes everything else clearer, just as rolling off the treble makes your bass 'bassier' on top of that deep bass often sets off room resonances which can muddy the sound. We don't hear those very low frequencies that well anyway so don't miss them that much, in our studio recordings recently I cut everything below 50Hz form the bass, you could barely hear the difference on the isolated bass (sadly the filter added no talent) but it cleaned up the overall mix nicely especially on the sort of small speakers potential bookers are likely to listen to. You'd think that the more bass the better, but it ain't always so. Part of the 'sound' of the speaker, I'd argue easily the most important part is how it portrays the bits we can hear well, the mids. It may well be the Berg does mids similarly to the Trace, so happy days. Equally it may be that the lack of deep bass is an advantage in terms of clarity and punch, as I've explained above. Bill's response curves are of the same driver in sealed v's ported cabs, it's quite possible to choose a driver and design a ported cab which will have a bottom end that rolls off in a very similar way to the sealed cab in his example. The bass handling of a speaker is the combination of both the nature of the driver and the design of the cab The final part of the puzzle is that what we hear depends upon how our ears and brains work together to interpret sound. What we hear as bass is often sounds above 100Hz. Just turning up the mids and treble makes us think there is less bass. Our ears are so insensitive to 30Hz for instance that even if the speaker is good in that area we won't notice a 30Hz filter because all the other sounds in music drown it out anyway. It may well sound deeper if you port it and how it sounds to you and anyone else is what matters, not the output at one particular frequency. In this case however I kind of see what Ashdown are saying but I don't think it's helpful. If you go back to Bill's graphs then that is what they are predicting will happen with your cab. The speaker won't be any different above 200Hz as Bill says so it won't be louder. In his first graph you'll see just a touch more bass around 80Hz which you will notice (the exact frequencies boosted will be different in the Ashdown) but you'll get better power handling in the bottom octave which Bill shows in the bottom graph, so when you turn it up you'll be able to make more bass noise before it distorts with the ports. I'd say it will sound bassier to you.

PS a midrange driver is also called a squawker.

I don't think the hosepipe analogy works when you bring frequency into play. A speaker isn't a 'pure' resistor, as the coil moves inside the magnetic field it generates an electric current which is out of phase with the driving current which makes the impedance rise. So yes the impedance rises with frequency and bringing in a second driver at high frequencies shouldn't stress the amp. There are problems of just introducing a midrange driver with only a simple HPF. both speakers will be producing sound around the crossover point and because they are physically separated you'll get interference between them and response irregularities. That will depend upon the exact drivers, some drivers roll off naturally at fairly low frequencies and this approach will work OK, others will have a big midrange peak (like the Eminence Beta 12)and you'll get potential problems. The Beyma has a fairly flat response in the midrange. The truth is though that both speakers are producing equal volumes at the crossover point and you always get some crossover artefacts with passive crossovers. In the case of a simple HPF they are worse but lot's of commercial designs use them, rather than Stevie's 'proper' crossover. In a way it's only one step up from using an old school mix of drivers, but these are intended as instrument speakers and some people like a bit of character/response irregularity. I'm not aiming at FRFR with a design like this, just a DIY tweak that people can do cheaply and simply. As to the enclosure for a midrange it needs to be pretty much as small as you can make it usually. I go for a 'critically damped' sealed enclosure with a Q of about 0.5. More about that later.

I had to listen to check. Love the rhythm though.

One of the advantages of a mid range driver is crossing down at a lower frequency, a 12" speaker is already beaming at 1kHz. the larger driver will usually handle more power than most compression drivers too. Years ago I bought a couple of 6" units to try with the Mk1 Basschat 12 but never got around to trying it. I had planned originally to build it into a separate sealed cab and try it with an active crossover to find out the sweet spot for the crossover, I was also going to try it with a 6dB/octave high pass filter built in to see if it could be offered as a design to owners of other cabs to use as a kind of 'bright box'. The downside is that even a 5" driver starts to beam at quite low frequencies and operates under cone break up above this so you won't get as clean a top end as with a horn tweeter. You kind of have to decide whether mids or the top end are your priority. There's an alternative to consider , which I wish I had built at the time to get bragging rights on Build something like the mini line source speakers that are described in the recently closed Markbass thread. Using a 2 or 3" driver would be ideal for bass. It'd go high enough to cover all you'd need in the way of top end but would let you have a lower crossover frequency so the mids would have an equally controlled dispersion. The downside is that a single driver that size wouldn't be loud enough. However a line of four would give you the increased power handling and efficiency you'd need and as a bonus a vertical array of drivers would give you a nice wide, flat, fan shaped radiation pattern. Someone beat me to it https://www.genzleramplification.com/shop/bass-array12-3/ I'm still looking to do this as my next project, if you want to go ahead then I'd be really interested in helping, and it may stimulate me to actually get into gear and build the one I've been planning for years.

I hope this hasn't been too confusing so far All of the information given so far is good but I'm not sure how easy it is to follow. I think you may have a mistake in your question, if you change it into ' if I have one cab A at 200 cubic cm and cab B at 450 cubic cm, is cab B louder? Is it moving more air' then it makes sense. Displacement is the volume of air displaced when the speaker cone moves through it's full undistorted range. In this case the answer would then be yes, it moves more air. As to how important this figure is, well it's one figure amongst many, it's important but not without all the other figures. Barefaced use it a lot in their adverts because their drive units are very good in this area and Alex Claber regularly posts in this forum so it has become a significant quality factor for many people. To be fair I don't think he has ever claimed it's the only important factor or made false claims but some of his fans have jumped upon it as being the key figure by which speakers should be judged. Over the last couple of years it has become a figure people on BC have fixated upon. I'm going to use the car analogy I'm afraid. The volume displacement of the speaker is like the capacity of the engine, it's the piston area times the stroke length. But , the cubic capacity of the engine won't tell you its power and the cubic capacity of a speaker won't tell you how loud it is. That also depends upon how efficient the speaker is, not all it's movement is converted into sound. A 2 litre engine is likely to be more powerful than a 1litre engine but you will know that isn't always true, I've just traded in my 1.6 litre VW for a more powerful 1.0 litre Vauxhall. If Vd is too low then your speaker isn't going to be able to make lot's of undistorted bass. If your goal is a small loud lightweight speaker then high excursion and therefore Vd becomes very important. If you can't displace enough air then you can't make sound above a certain volume and bass frequencies need a lot of air shifting. If I was designing a 10" high performance speaker I'd be proud if it had Vd Another factor though is efficiency. If you double the cone area and keep everything else the same then you'll get an extra 3dB for the same power. It's quite possible for example that if you took two 10" speakers with Vd of 200cm3 they might be louder at 300W than a single 10" speaker with Vd of 450 cm3.'t I couldn't tell you for sure without all of the figures. The physics of speakers isn't that hard, if you've got 'A' level science or maths you'll have no trouble, GCSE maths is enough if you are interested enough but plucking any single figure out of the air isn't going to explain much, you have to do the maths. I the end I don't think Vd is very helpful to the average bassist. Yes it's particularly important that small speakers have good excursion but in the end that won't tell you how they sound. You wouldn't buy a car without a test drive or choose the engine size without considering other factors first and I don't think you should choose a bass speaker like that either.

No, I'm incredibly old but never smoked, no health issues and I'm pretty fit, gym and cycling/walking. Any YT coaches you'd recommend, there are sooo many it's hard to know, and they contradict each other a bit.