stevie

[quote name='redstriper' post='222329' date='Jun 19 2008, 05:11 PM']The wire is not soldered to the speaker so no problem at that end and I can fit a jack plug to the cab and solder the speaker wire to it. Re: attaching the wire from the amp to the 2 jack sockets to give the possibity of an extension cab - Do I split the 2 wires and solder them to each socket identically and would this give 2 x 8 ohm outputs?[/quote] The wire should be marked positive and negative in some way - either by colour or by a stripe. You solder each of the two wires to the two connectors/tabs on the first jack socket, which should also be marked positive and negative (the positive one is the one furthest from the input). You then wire from the positive and negative of the the first socket to the positive and negative of the second socket. That's it. It might be worth checking if the holes aren't for XLR sockets rather than jacks - they could well be. If they are, the hole will be about 23mm in diameter. Let me know, because I could send you a pair of Speakons to fit. I''ve got some new ones I don't need. For your bits and pieces like handles and feet, you could also check out the Blue Arran website, which is pretty good. Your speaker looks like a Fane 15B, which is a very, very nice driver.

[quote name='chris_b' post='222231' date='Jun 19 2008, 03:31 PM']I upgraded my pickups to Bartolini and got a massive improvement in the tone. Later I thought I'd got the rest of the way and put a Jazz bridge pickup in and an active pre amp. The J pickup wasn't worth it as it made very little difference to the tone! Just my experience.[/quote] My experience, too. I've got a Yamaha BB1100S with a P/J setup and the Jazz does nothing for me at all. It sounds like a guitar and I hardly ever bother with it. It's certainly useless on its own.

Meant to strip the pictures out before replying - sorry 'bout that.

[quote name='redstriper' post='222269' date='Jun 19 2008, 04:17 PM']Thanks again Stevie - that's really encouraging although I'm a hopeless DIYer - I ended up in casualty last time I tried anything and am now banned from Stanley knives for life. But this doesn't look too difficult, it looks like you screwed the pre amp directly into the ply wood and I guess the power amp is screwed separately to the back and/or base. My amp needs a slot for air vents as you can see in the pic - Another problem is that the amp is hardwired to the speaker although there are holes for 2 1/4" jack output sockets that are not installed. I'm not sure how to wire these correctly from the 2 wires that now go to the speaker. [/quote] You're welcome, red. I think I glued a small piece of plywood at the front to double up the thickness to take the screws. At the back, I might have glued a small piece of softwood to take the screws. I just used the mounting holes provided. Not rocket science. The rear output was already connected - so I just unsoldered the cable to the speaker. You would have to unsolder the speaker wire at the speaker end, fit a couple of jack sockets and connect the wire to the jacks. I'm not sure if that would be a step too far for you, but it is a very easy soldering job. You would probably also have to duplicate any vent holes in your existing cab. Anyway, I'll take some pictures at the weekend so that you can see in detail what I did. But I can see you get the picture. Might be worth a try. You can always fit the amp back to the cab if it doesn't work out.

Here you go. You would need to buy the plywood, handle, feet and paint. You could of course use a different handle, or put the handle on the top if you like.

[quote name='redstriper' post='222178' date='Jun 19 2008, 02:28 PM']Thanks Stevie, I have considered replacing the speaker and it is an attractive option financially, but a bit risky not knowing how it will sound in the cab. It would also reduce the weight considerably if I could remove the amp and put it in a separate case, but this is not quite so simple because the pre and power amps are 2 separate parts, the pre amp is rack mountable while the power amp is screwed to the top and back of the combo. If I can overcome these technical problems, I will give it a go because I am happy with the sound if not the weight.[/quote] I had exactly the same problem with my Ohm combo, which is not too dissimilar to yours. I removed the head section - which also has a separate preamp and power amp - and made a sleeve for it out of 1/2 inch plywood. I fitted a nice leather handle to one end, some rubber feet, and painted it black. It really looks quite good and is a very easy one-handed carry. You don't need to be a carpenter to do it, but it will take you a weekend unless you're a DIY whiz. I'm actually using a different cab at the moment, but I've still got the Ohm one here. I'll try to post a pic later and could also post some detailed pictures at the weekend if that would help. Come to think of it, this could be something others might have been considering doing.

Just to add to the many good suggestions - replacing the speaker in your Trace with a neodymium model would cut the weight of your combo by about ten pounds. I don't know if that would be enough. You might even consider it as an interim measure, as it would be a lot cheaper than the alternatives.

[quote name='lowhand_mike' post='221559' date='Jun 18 2008, 05:20 PM']give it a rest guys. stevie if you can provide a link to prove your point then please do so as it would be informative reading (i'm a geeking it up tonight ) i'm sure if you could actually prove this information then it would be of great benifit to bill where as bill info has always been well backed up. otherwise can it. :ph34r:[/quote] Here you go ,mike. [url="http://www.htguide.com/forum/showthread.php4?t=29184"]http://www.htguide.com/forum/showthread.php4?t=29184[/url] Have a look at the post from Kal Rubinson, a well respected audio journalist who writes for Stereophile. He says: "Yes. 1/2 wavelength is the generally accepted spacing maximum. Dunno about d'Appolito's standard but ANY two drivers spaced more than 1/2 wavelength apart and reproducing the same signals will show destructive (and constructive) interference in the plane OF their displacement." There's plenty more if you look for it. I'm bowing out of this discussion now, as it is getting nowhere and I've had enough of the insults.

I notice you are still perusing the board, Bill. I thought you had better things to do.

[quote name='Bill Fitzmaurice' post='221538' date='Jun 18 2008, 04:58 PM']Stevie, the one compliment I will pay to you is that you remind me very much of the Honorable President of the United States, George W. Bush. Like he, everytime you open your mouth you somehow manage to stick your foot further down your throat than the time before. Your above statement is complete and utter gibberish. I'll let Alex point out why if he cares to, I have far more important things to attend to. Cutting my toenails is first on the list.[/quote] That really is not a very convincing reply, but I must accept that it's the best you can do.

[quote name='Bill Fitzmaurice' post='220890' date='Jun 17 2008, 07:43 PM']Stevie, you'd have a lot more success arguing the fine points of loudspeaker design if you understood any of them. If you did you'd know that drivers may be placed on the horizontal plane if they are crossed over below the frequency that is 1 wavelength at their CTC spacing. Debating the laws of acoustics is a waste of my time, as being laws they are not subject to debate. I'm usually quite patient at explaining said laws and how they affect gear choices to those who have an interest in furthering their education. OTOH you strike me as one who clearly has already acquired all the knowledge he ever cares to, and that being the case please refrain from wasting any more of my time.[/quote] 1 wavelength is way too much for interdriver spacing. Anyone who familiar with the laws of acoustics would know that where the time displacement between two low frequency drivers corresponds to one-half of one wavelength, the outputs of the two low frequency drivers will null. 180 degrees and all that. Spacing needs to be less than half a wavelength. Back to the Loudspeaker Cookbook for you. It's interesting that you use the term 'debate' here, because I have not seen you debating on any of the threads you have been involved in on this forum - merely pronouncing, and belittling others.

[quote name='alexclaber' post='221428' date='Jun 18 2008, 03:06 PM']Aha! "This entire thing goes back to the Eleanor Powell "double tap" incident at MGM studios in the early 1930s. When monitoring playback of Powell tapdancing an echo was noticed on the taps. John Hilliard, subsequently the greatest of all horn designers, was a young sound engineer at MGM and traced the problem to the 8 foot difference in the path lengths of the horns in the 2-way Western Electric monitor speaker. Hilliard did experiments that showed that the effect was time and frequency dependent and that a delay of less than 3 milleseconds (about 3 feet) was inaudible using crossvers between 350 to 800hz. A result of this incident and WE's refusal to market their improved Fletcher loudspeaker was the decision of MGM sound honcho Douglas Shearer for MGM to design their own improved system which would among other things minmize time delay. Hilliard was put in charge of the project which then developed the famous Shearer Horn. An entire galaxy of talent worked on this system including Hilliard, James Lansing, Bob Stephens and even RCA's Harry Olson. Note that though the folded basshorn of the Shearer cut time delay compared to the WE snail horns it didn't eliminate it totally but Hilliard's later Altec Voice of the Theatre did. So it seems that even though Hilliard thought some delay was inaudible the existence of any at all still nagged at him." Alex[/quote] So, would it be fair to say that Youngatheart is OK to stick a 1x15 on top of his 2x10 if Eleanor Powell's tapdancing sounds OK through the rig? Or not?

[quote name='alexclaber' post='221271' date='Jun 18 2008, 11:48 AM']How many bass cabs do you see with midrange drivers? It's a very short list... A 4x12" is a side-by-side design. 2x12" guitar amps, whether open-backed or not, consistently work better if you turn them on their side - it gets the speakers closer to ear level and significantly improves off-axis response. If you can persuade your guitarist to do this it can do wonders for the sound of your band, I know my guitarist is a total convert. Personally I don't have a problem with people doing whatever they like to get the sound they want - but surprisingly often their decisions are based on faux science and witchcraft rather than the claim of just using their ears! If you are going to use science to aid your decisions, use good science! Alex[/quote] Indeed it is a short list - more's the pity. I certainly think a midrange driver is of more value than a tweeter for bass. I suppose a 4 x 12" could be considered a side-by-side design. Limiting vertical dispersion to control unwanted reflections is common practice but a 4 x setup limits dispersion by lobing both vertically and horizontally. So, to be fair, it's not strictly side-by-side. I'm not arguing against positioning a 2 x 12 or a 2 x 10 vertically, by the way. On the contrary, your experience is perfectly valid and there are sound technical reasons why it should be so. What I don't agree with is the blanket statement that the only, or best, way of arranging the speakers in a bass rig is in a column. But there has already been some backtracking on that assertion. Use good science, of course. The problem is knowing what is good and what is bogus. Or perhaps more aptly, what is important and what isn't.

[quote name='lowhand_mike' post='220785' date='Jun 17 2008, 05:39 PM']basically stevie take a look at this, it should explain everything. [url="http://basschat.co.uk/index.php?showtopic=21267"]http://basschat.co.uk/index.php?showtopic=21267[/url][/quote] Oh dear me, it gets worse!!

[quote name='Bill Fitzmaurice' post='220794' date='Jun 17 2008, 05:56 PM']Foremost, placing drivers horizontally.[/quote] Shouldn't that be placing drivers horizontally without crossing over to a midrange unit? Leo Fender and Jim Marshall didn't make sde-by-side bass cabs in the 1950s. Marshall bass cabs were 4 x 12, 1 x 15 and 1 x 18 and Fender had the Bassman, which was a 1 x 15. The side-by-side 2 x 12s these companies built were guitar amps. The Fender Twin and the Marshall Bluesbreaker (and the Vox AC30 before it) used open back cabinets based on a perfectly valid dipole design that still enjoys popularity today.

Studio monitors from ATC, Quested and Dynaudio, by the way. And when these guys need four drivers, guess what?

[quote name='Bill Fitzmaurice' post='220794' date='Jun 17 2008, 05:56 PM']Foremost, placing drivers horizontally. For an example of how drivers should be placed investigate the circa 1950 PA installation in St. Paul's Cathedral in London, which was only recently upgraded because it worked so well for a half century plus despite being in the most difficult of environments. Assumption is Jim Marshall was not a parishoner.[/quote] You think a bass rig should be designed on the principles of a public address system? The mind boggles. Of course, if you are going to build column speakers, placing drivers horizontally is a no-no. Similarly for hi-fi, where slim cabinets are fashionable. By 'placing drivers horizontally', I assume you mean like this:[attachment=9729:SCM200ASL_Pro.JPG]

[quote name='Bill Fitzmaurice' post='220024' date='Jun 16 2008, 04:55 PM']+1. The engineering used by the vast majority of musical instrument cabs has not changed significantly since the mid 1970s, and it was 30 years obsolete even then. If either Leo Fender or Jim Marshall had possessed beyond a rudimentary knowledge of audio theory in general and loudspeaker design in particular the vast majority of musical instrument speaker topologies introduced since 1955 would never have appeared in the first place. Fender was a machinest who didn't even play guitar or bass, and Marshall was a drummer. Their method of speaker design was 'stick some drivers in a box'. Unfortunately they set a flawed standard that still dominates the marketplace today.[/quote] I think you'll find that Leo Fender was an accountant by profession. I must say, I've never heard a guitar of bass player who has ever expressed anything but the utmost admiration for both Leo Fender and Jim Marshall. In fact, whenever anyone mentions that Leo Fender wasn't a guitar player, it's always to draw attention to the enormity of his achievement in producing the designs he did. What exactly is this "flawed standard"? Can you be more specific?

[quote name='Bill Fitzmaurice' post='219597' date='Jun 16 2008, 02:39 AM']'No trouble' is a matter of opinion. Mine is that of a bass player who also happens to be an audio engineer. As for specific examples, that would be the simultaneous using of any two cabs that don't have identical phase response. Since no two cabs that don't use identical drivers in identical alignments can have identical phase response that makes every use of non-identical cabs a specific example. I'm not saying they can't sound acceptable, but they would sound better properly matched. Amongst other things. Just the instrument cab industry. The hi-fi, theater and PA guys got it right a half century ago, the instrument market segment is a wee bit slow on the uptake. [/quote] So, in your audio engineer's opinion 2 x 15s or 8 x 10s will always sound better than a 1 x 15 and a 4 x 10 because they are "properly matched". Is that right? And bass players, unlike the hi-fi, theatre or PA guys, have failed to realize this because they are "a wee bit slow on the uptake". Bill, have you heard of a book called "How to win friends and influence people"?

[quote name='Bill Fitzmaurice' post='219554' date='Jun 15 2008, 11:35 PM']I'm assuming he is not using a crossover. Tens will naturally have a wider midrange dispersion angle and a higher frequency response than fifteens, so the caveat applies with or without being crossed. Because no manufacturer had, or has for that matter, any incentive to do better when they sell all the mediocre high profit margin junk they can crank out. And bassplayers are artists, not engineers, so by and large they just don't know any better.[/quote] Correct me if I'm wrong, but isn't midrange dispersion a function of total radiating area? In other words, a single ten will have a wider midrange dispersion than a single 15, but two tens won't. Are you seriously saying that no manufacturer of bass gear has any incentive to produce anything but mediocre, high profit margin junk because their target market is too ignorant to appreciate it? That's a bit arrogant, don't you think?

[quote name='bass player spinn' post='209187' date='May 29 2008, 09:32 PM']cool so i prob need to look at the vintage one? thats a tip i got from someone else to.. thanks much..[/quote] You *never* see any of the vintage SPB-1s for sale secondhand (because players hang on to them). Hot pickups for bass are just a marketing ploy. What you want from your pickup is *tone*, not output. Increasing the output of a pickup normally results in higher inductance, which cuts the higher frequencies and gives you a muddier sound. The same principle applies to guitar, of course, although there are times when fitting hotter pickups to a guitar can be worthwhile (the bridge position on a Strat, for example).

I've tried all the Duncans for P-Bass apart from the Antiquity (which sounds like a total rip-off to me). The SPB-2 was a bit muddy. The Quarter Pounder was punchy but lost quite a lot of the bass's tone. The Vintage SPB-1 was superb. Very close to the SPB-1, but with a slightly deeper bottom end and the same kind of punch as the Quarter Pounder, was the active APB-1. I bought the APB-1, although I'd be interested to revisit the SPB-1 sometime. Just one man's experience.

The original Bass Pod seems to be selling for quite an affordable price now on eBay. I want one mainly for the compressor and the eq, and perhaps for some of the amp models (I'm not interested in the effects). Would I be better off spending more and getting the XT version?