stevie

I had a TC Electronics bass preamp a while back - basically a four-band parametric eq - which I sold when I decided that dinky lightweight amps were a good idea. After that excursion, I tried to get hold of another one but they are difficult to find - so I bought a Behringer four-band mono parametric which, to my ears, is just as transparent. I'm using it with a Rauch or QSC power amp depending on how much power I need. The unbalanced input is perfect for bass and I have real control over my sound, and more importantly, the room I'm in. It's a bit more messing about, but setting it up with a RTA (on a laptop) gets me the fattest, cleanest, punchiest sound I could wish for. It's not for the faint hearted, however, and you really do need to know what you're doing to avoid messing up. Which is probably why it's a step too far for most people.

Some interesting stuff about Groove Tubes on there. Worth a dig.

All very sensible stuff so far. If the tops are sounding a bit thin you could also try overlapping the crossover frequencies if you are able to do that. Say, 120Hz for the subs and 80 Hz for the tops. And of course, you should also try swapping the phase of the subs or the tops and listening to the difference it makes. Use whatever connection gives you a 'fuller' bass sound. Measuring equipment makes all of this a lot easier, it has to be said.

Sorry if I didn't explain myself properly. The normal way to connect subs up is to use an active crossover to cut the high frequencies from the subs and cut the low frequencies from the tops. When you put the two together you get a nice flat frequency response with no overlap. In theory. However, sometimes it can sound better if you do have some overlap, especially if the tops have a relatively high built-in (acoustical) rolloff anyway. So, what I meant was, connect the subs in the normal way but try running the tops flat (full range) without allowing the crossover to cut the low end.

[quote name='chris_b' timestamp='1367318152' post='2064029'] Ooops. Were you awake when you typed that? [/quote] Now why would you think that, Chris? I've been up and hard at work for several hours.

[quote name='wateroftyne' timestamp='1367315050' post='2063965'] You can tell that from the photos? [/quote] Not from the photos, but it's a fair deduction from the technical specs. I'd be happy to be proved wrong though.

Looks like a Deltalight and a cheap bullet in a thinwall cab. I must be missing something here as I don't see anything to get excited about.

You'll eventually have to spend a little time figuring out where the optimum crossover point is. I agree 120Hz is a good place to start. A lot will depend on how low your top boxes go. Don't forget the option of running the tops full range and just rolling off the subs. That can sometimes work.

[quote name='Mr. Foxen' timestamp='1366205817' post='2049579'] Correct, it is an article about speakers, and how damping factor is irrelevant, so being a valve amplifier is thus irrelevant. That is the whole point. [/quote] At the risk of stating the obvious, you can't prove a point about valve amps by quoting an article that has nothing to do with valve amps.

[quote name='Mr. Foxen' timestamp='1366157081' post='2049162'] Modern speakers are plenty damped all on their own. Modern like not 1930s. If damping factor was an issue, cabs would sound significantly different depending on if they are wired in series or parallel. [url="http://www.cartchunk.org/audiotopics/SeriesSpeaker.pdf"]http://www.cartchunk...riesSpeaker.pdf[/url] [/quote] That article was published in 2000, forty years after valve technology went the way of the dodo for most people. He wasn't talking about valve amps.

Valve bounce, eh? It's a term used in vehicle mechanics. From Wikipedia: "[b]Valve bounce[/b] is a related condition where the valve does not stay seated due to the combined effects of the valve's inertia and resonance of metallic valve springs that reduce the closing force, and allow the valve to re-open partially."

Chris bought a pickup from me. Payment came through quickly and as agreed and everything went swimmingly. Good bloke! Stevie

Yes, it’s quite clear what you mean, hamfist. I can’t give you a definitive answer on this but I can tell you how to find out. All of the bass cabs with tweeters I've examined so far have crossover components on the tweeter but nothing on the bass. The bass unit is normally wired directly to the input and in theory rolls off naturally where the tweeter rolls in. So the chances are that what you are hearing from the bass units is what they actually sound like full range: you’re unlikely to get any more treble out of them. I can’t be 100% sure because I’ve never looked inside your cab. If you want to take a look inside, trace the wires from the input to the bass units. If there is an inductor (coiled enameled copper wire) at some point in the circuit you should simple bridge it with a piece of wire to take it out of circuit (solder for a permanent job). That will make the bass units brighter. Make sure the inductor is connected in series with the bass units though. There is likely to be an inductor across the tweeter: bridge that and you could be in trouble. In the extremely unlikely event that there is a coil *and* a cap on the bass units you will need to disconnect the cap as well. I’m just covering all eventualities – I don’t think you’ll find one.

I (and I assume others who have participated in this thread) was asked yesterday evening by a mod not to participate any further in this thread. That is their privilege and I will respect that. I would just like to point out that, if you read the thread from the beginning, you will see that I have not criticized anyone personally nor have I insulted anyone. My remark to Bill pointed out by BluRay and BassTractor was over the top, however, and I apologize for that.

[quote name='Bill Fitzmaurice' timestamp='1361904095' post='1992866'] No. This is normal. If there was a dip below 5 ohms in the region where 75% of the power demands lie for electic bass it would be an issue, but that region lies below 500Hz. [/quote] Why would you say that? Of course it's not normal. The impedance should remain above nominal across the entire passband of the speaker and the manufacturer quotes a usable frequency response of 40Hz to 9kHz. What if your keyboard player uses it? Is there anything in the manual saying they shouldn’t? I can see why you’re jittery though. Roger’s done the right thing and employed you to OK the technical performance of the speaker and you messed up. In theory you are now liable for the cost of recalling and modifying all the Baer speakers in the field to meet the published spec. Nice one!

There's not much energy at 3kHz unless you're slapping really hard - so you're quite likely to get away with it. It's difficult to quantify the risk really. But there shouldn't be any risk at all.

The acoustic measurements are perfectly consistent with the description of the box in the review (esp. the crossover to the mid unit at 1500Hz) and with the impedance curve shown. The impedance measurement is completely independent of whatever mic measuring technique is used and is certainly quite accurate.

[quote name='wateroftyne' timestamp='1361888713' post='1992491'] There's a place for tongue in cheek - not sure this is it? [/quote] I did say in the first line that it wasn't really a review.

Based on several decades of working with such things. The data is consistent.

[quote name='wateroftyne' timestamp='1361887521' post='1992454'] Stevie - it's a bit unfair calling it a review, don't you think? [/quote] A bit tongue in cheek. What would you prefer?

[quote name='Bill Fitzmaurice' timestamp='1361886741' post='1992443'] All of that assumes that the Bass Gear chart is accurate. It is not. Why has already been explained in great detail. And as they have always used the same flawed measuring technique every chart they've ever published is not accurate. I don't see that you've been breaking every other manufacturers balls over the disinformation published by Bass Gear, so why you're picking on Baer suggests a personal agenda. And it reminds me why I long ago put you on my ignore list, and why you're going back on it after this short hiatus. [/quote] It looks accurate enough to me. Just because they're not using ground plane doesn't make the measurements invalid. So why don't you argue the facts instead of attacking me personally?

We should now keep our eyes peeled for lots of £49.99 bargains!

[quote name='Dave Vader' timestamp='1361878177' post='1992209'] Probably no replies because it seems perfectly reasonable. [/quote] I think so too. It's a very intelligent solution to the problem.

Review of the Baer ML112 Well, not really a review as such, but I thought I’d flesh out my earlier remarks for those of you planning to audition the Baer cabs. Here are a few pointers gleaned from the measurements from the Bass Gear test that may be of help. I’ll try to keep it salient. The first thing you notice on the Bass Gear frequency response plot is the first thing you will hear when you listen to the product. There is a large (6dB or so) peak at around 1600Hz which is the main breakup mode of the bass driver. This peak comprises distortion and delayed resonances (‘ringing’) and is fairly typical of some Eminence LF drivers. Normal practice is to neutralize such peaks by putting them well out of the passband. These are resonances, not unlike cabinet resonances, and are normally undesirable. One of the benefits of using a midrange driver is that you get to take these “nasty" breakup frequencies out of the equation and replace them with a nice smooth, clean, uncoloured midrange. There are several other benefits of this arrangement, including directional consistency up to a much higher frequency than the bass driver can manage on its own. However, because the crossover frequency of the ML112 is at a very high 1500 – 1700 Hz (where you would expect to cross to a 1” compression driver like in Duke’s AudioKinesis system) this speaker gains few of the benefits of a bass/mid design where the transition normally takes place much lower (at around 600Hz). It’s almost as if the midrange driver in this system were being used as tweeter. The sharp cancellations in the off axis responses show that the crossover design is flawed (the off-axis curves should be smooth). This is also likely to have a negative effect on sound quality in this area. Finally, also as a result of the crossover design, the impedance curve of this 8-ohm-rated cab drops below nominal at around 1500Hz and drops further to around 4 ohms at 3kHz. This is quite a serious design fault and means that the product does not meet one of its most important specs. Whether you will damage your amplifier by using two of them is anyone's guess but if I were considering laying out money for one of these cabs, I would be happier if I knew the manufacturer had the technical expertise to avoid this kind of problem in the first place. There’s more, but I think that gives you a few pointers. The main thing I would listen for when auditioning these would be whether I could live with the large resonant peak built into the cab, because it will dominate anything you play through it (and because it’s a resonance, it will be there to some extent even if you try to dial it out). Anyway, I’m sure you’ll all make your own mind up and the final arbiter is your ears. If you like it, get your credit card out and buy one. It’s your money.