Bill Fitzmaurice

Most recordings since the late 60s were direct to the board, because the speakers of the day were so poor. To the extent that amps were used in the studio it was as monitors. James Jamerson was known for using an Ampeg B15, but he almost always went direct, using the same Motown DI direct box now sold by Acme Audio. https://reverb.com/item/4394324-acme-audio-motown-d-i-wb-3-direct-input-box?bk=eyJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJmZDdmYTI4OC1lODRkLTRkOTktYTI4NS1kZmU3ZmRkODA1ZjYiLCJpYXQiOjE2NzY4OTk1ODAsInVzZXJfaWQiOiIiLCJzZXNzaW9uX2lkIjoiOWYzOTNiMWMtOGM3ZS00NmI4LTg4ZjgtMjgyMjBkZDQ4MDJiIiwiY29va2llX2lkIjoiZDI5ZDI5N2QtYjIzNS00NWQ3LWE4NDAtMDA2NTFmYjdiMjc0IiwicHJvZHVjdF9pZCI6IjQzOTQzMjQiLCJzb3VyY2UiOiJOT05FIn0.7kZRDnlmhcQeqDRlfrndRM4mKyYWa2Gu9Wg-jhwje7A

1 hour ago, Marcus Cornall said:

1. I am considering an amp containing a tube.I have never had one before. Try not to laugh! 

I didn't have the income for a proper amp before either.

I am considering it because I would like a more 'vintage ' sound,which at the moment is what comes out of my Cort-essentially a rw P

Vintage sound doesn't come from a pre-amp tube. It comes from a power tube output section, which between the natural compression imparted by them and the output transformer imparts response that can only be more or less duplicated with amp emulation DSP.

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Question 2  is ...what size of wattage of amp would you use with a BB II in those circs?

Between 1/2 and 2x the speaker thermal rating. Knowing that low price amp specs can't be trusted I'd avoid those.

2 hours ago, Marcus Cornall said:

  But you can hear those freqs.i can anyway.

No, you can't. What you can hear when playing tones below roughly 30Hz is their harmonics. Even if the source is a tone generator that only produces sine wave fundamentals harmonics are still there, created by the speaker. If it's a square wave generator harmonics are there in spades, as what makes a square wave square is harmonics.

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my Reggae bass taste personally is to sound as purely 'fundamental only' as possible

You may think that's the case, but electric bass produces mainly harmonics, especially below 100Hz. Classic reggae tone is primarily 2nd and 3rd harmonics. This is an RTA of a PBass playing an open A string. Most of the energy is in the harmonics. With lower notes there's even less fundamental and more harmonic content, and this is with the pure signal from the bass. The coloration imparted by the speaker results in less fundamental content.

Figuring out what's going on with just ones ears is daunting, even if you know the physics. That's where measurements come in. That used to be an expensive proposition, but not today. Download this to your phone: https://play.google.com/store/apps/details?id=com.dom.audioanalyzer

Set it to Sound Analyzer, 1/3 octave bands, C weighting, Slow weighting. Ideally you want to input a pink noise source into your amp. You can download a pink noise loop to your PC. With that you can see in real time the effect of moving the cab. The phone needs to be placed where your ears would normally be with respect to the speaker, and not moved during the testing. That's critical, as even a slight change in the mic placement will alter the result. http://ethanwiner.com/believe.html

2 hours ago, jrixn1 said:

 

 

Hi @Bill Fitzmaurice

My understanding is that subs are omnidirectional.

All speakers are below the frequency where the baffle is one wavelength across. Above that they shift to directional. As you keep going higher the radiation angle keeps shrinking. Since a wavelength at 100Hz is 3.4 meters it takes a large cluster of subs to be directional.

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In that case, is there any point in any speaker on stage (backline or monitors) reproducing frequencies below 100Hz?

It depends on how far the backline is from the subs. But by and large if you're getting a lot of output from the subs on the stage it's mostly below the frequencies that your backline cab is producing, the fault of a sound man who doesn't know what he's doing. IME the #1 fault in concert sound today is sound men pushing the bass at lower frequencies and higher levels than they should. I had the pleasure of seeing 'Tower of Power' tonight and the sound man actually got it right. It's a good thing, if he'd turned fabulous funk bass into a boomy unintelligible mess I'd have had no choice but to hogtie him and hijack the board.

Looking at a picture the port is so close to the rear of the cab that if that's happening it's minimal. As for the Hybrid Resonator, I don't know what it is. Possibly a dual chamber reflex, which would explain the port placement, and the description of what it does. Nonetheless for the space between the cab bottom and floor to act as an effective extension of the port it would have to be placed in the middle of the bottom.

1 hour ago, Obrienp said:

Well, I’ve given the Markbass Tilt Stand a couple of tries and I have decided it’s not working for me and the BF One10. It put the cab in a great wedge monitor style position but all coupling between the cab and the floor was lost. This seemed to get rid of a large chunk of bass and make the mids very prominent.

In order to lose the coupling between the floor and cab the cab would have to be lifted at least 60cm off the floor. No bass was lost, it just seems that way because you're hearing mids and highs that you weren't before.

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I think this would be less of a problem with a front ported cab but the One10 has the port on the bottom in portrait mode, so it just vented into the air rather than deflecting off the floor.

That doesn't make any difference either. The port frequencies are lower than those from the cone, making the wavelengths longer, so the port would have to be even further from the floor to lose coupling, at least 150cm. If you're running with the same EQ on the stand as you did before that explains the mid content being more than what you want.

1 hour ago, Marcus Cornall said:

But it would also seem from what you say,that running ,say a 500w amp actually giving  say 350 into the single BB 12  wouldn't be enough to drive the driver properly then?

There's no such thing as enough power to drive it properly. There's only enough power to go as loud as you need to. That could be 100 watts, it could be one. How much is enough? The Ampeg B15 is 30 watts. Horses for courses.

The more watts the louder, yes, but running either an amp or speakers to their limit isn't a good idea, for their longevity or that of your ears.

Compare this to a car. Let's say the speedometer goes to 240 KPH and the tach goes to 7,000 RPM. That doesn't mean you should be driving 240 KPH at 7,000 RPM. You can, but probably not for long. The car has that capability so that it will run for ten years or more at 120 KPH at 2500 RPM. 

How many watts is enough? Between one half and twice the speaker thermal rating. One half is usually enough to drive a speaker to its mechanical limit. Twice gives you more amp headroom, which gives cleaner tone.

If your amp can only deliver half the speaker's mechanical limit that's at best -3dB from the speaker's maximum output. -3dB is audible, but just. As for linearity of power versus loudness, it isn't. It's a logarithmic relationship. That's why I said the first 100 watts are the most significant. That gets the average speaker output to the vicinity of 115dB at one meter. 115dB for extended periods will cause hearing loss. (Just ask Pete Townshend. You'll have to speak loudly.) Luckily we tend not to stand 1 meter from our cabs, but still, it's louder than we usually play at. A more reasonable 109dB takes only 25 watts. Where the next 75 watts come in is headroom, again so you're not running the amp at it's limit.

Going beyond 100 watts, if for some silly reason you want it twice as loud 200 watts won't do it. That only gets you to 118dB. Twice as loud as 115dB is 125dB. That requires 1,000 watts. Not that it matters, at that level you'll go deaf in short order. The only advantage to having 1,000 watts over 100 watts is that it gives you 10dB additional amp headroom, so that you won't clip it on hard transients. But with a realistic 25 watt average draw you only need 250 watts for 10dB of headroom. 

The last factor comes down to specsmanship, the fudging of data by marketing departments. The higher the stated power output the more likely the marketing department is writing cheques that the engineering department can't cover. Some companies are famed for doing this, TC and Bugera being two. Some have a well earned reputation for honesty, Ampeg being one. If only there was a comprehensive independent testing source to separate the wheat from the chaff, but there isn't. This is where cost versus claims comes in. If the price makes it seem to be too good to be true it probably isn't.

1 hour ago, Marcus Cornall said:

So you don't have to put the full 800 into the cab to get the best sound +/ loudest output from it then?

No, and for that matter chances are you may never put the full 800 watts into it. The first 100 watts are the most significant, and in most cases you won't put much more than that into it, other than as short transient peaks.

The 'ideal' size for the 3015 is 3 cu ft net tuned to 50Hz. 'Ideal', because you can go larger or smaller with the box size and the tuning, depending on what your priorities are. Commercial cabs tend to go smaller, sometimes a lot smaller, as their #1 priority is sales, and the current consumer trend is for smaller and lighter. My 3015 is in a 5.6 cu ft horn loaded enclosure, as my personal priority is maximum performance. I also have a ported design for the 3015 that's 'only' 2.5 cu ft, for those who's priority is more ease of transport. Every speaker makes compromises. What experience teaches you is where you can afford to compromise and where you should not.

Yep. Sealed cabs and older ported cabs have a natural roll off below roughly 80Hz. We compensated for that with the bass tone control, which started boosting around 200Hz, reaching maximum boost around 60Hz. When you do that with a modern ported cab that rolls off at 50Hz or lower it changes the character of the sound, from what we think of as vintage to what we think of as modern. All we have to do to get that vintage tone is to use EQ to roll off the low end below 80Hz, emulating sealed and higher tuned ported cabs. What's interesting is that if we'd had cabs that went flat to 50Hz or lower back in the day 'vintage' might have sounded quite different. Or not. Bass cabs didn't go very low, but neither did the speakers that most people listened to music with. The evolution of electric bass tone went hand in hand with the evolution of consumer speaker capabilities. One major complaint of younger drivers of BMW, and I'm sure other makes as well, is the audio  systems won't wake the dead two counties away with pounding bass. That's because the low frequency knee is around 60Hz with full bass EQ boost. I've got no complaint with the sound of my Bimmer, as the only music I listen to is Classic Rock. 😁

4 hours ago, Phil Starr said:

 

 Few meet the 100db/W even on the manufacturers spec

None do below 100Hz.

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Kappalite 15HO as the best all rounder

It's actually the Kappalite 3015. Xmax is 5.9mm, which is longer than average. It will take 450w mechanical through most of its range. The 3015LF goes lower, and will take 450w mechanical at every frequency, but lacks mids. That's OK if you use it with a midrange driver, or for a pure reggae all bottom no top tone. Otherwise it's not at all versatile. 

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Some specs I have in mind - 600 watt, 4 ohm, ported and able to deliver a 35Hz to 5khz range, at least 100db 1w @ 1m sensitivity.

To get that you'd need to use two twelves.

One thing to look for in an amp is an EQ section that allows you to boost at 100 Hz and cut at 50Hz. This will allow you to closely duplicate with a ported Barefaced the tone of the sealed SVT.

I use a lightweight 1x12. It's not small, though. I have a lightweight 1x15 as well, also not small. I hardly use it, for outdoor gigs only. Indoors the 1x12 is plenty.

Louder yes, but it's best to have the bass feed in the monitors high passed at 120 to 160 Hz. Side fills too. The backline provides all the low end either you or your band mates need on stage. It's only the directional frequencies, above 120 Hz, that need to be be spread around better. Part of the problem with spreading cabs and running full range into monitors and side fills is that it not only provides more mids and highs that you want but it also provides more lows that in most cases you don't. The case where you might need lows is on a huge stage outdoors. Feel free to run full range at Wembley. 😉 

FWIW don't split cabs. When you do it creates hot and cold zones in the lows, AKA 'Power Alley'. If you want to be heard on the other side of the stage aim one cab at yourself, the other across the stage. That aims directional mids and highs so they can be heard, without creating a power alley. This explains. It references PA subs, but applies to bass cabs as well: https://www.prosoundweb.com/the-power-alley-discussion-solutions-to-the-troubling-interaction-of-subwoofers/

Where tone is concerned reggae isn't low end strong in the 40-60Hz range, it's midbass strong in the 60-90Hz range. That's because the benchmark reggae cab, the SVT 810, isn't low end strong, it's midbass strong. It's also loud. The reason it's loud is the eight drivers, which have a combined cone displacement of 1300cc. If you want to get SVT volume without the SVT size and weight the way to do it is with high displacement drivers. The highest displacement drivers available in commercial cabs are those used by Barefaced. Four Barefaced tens or two Barefaced twelves will go almost as loud as an SVT 810. 

5 hours ago, DGBass said:

 It worked out at a cabinet tuning of approx 52-53 Hz. Sounds about right for a 15?

That's where the driver specs come in. The ideal tuning for contemporary high quality fifteens will be closer to 45 Hz, but as the saying goes they don't make them like they used to, so 53 Hz may be best for that driver. 

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you can measure the specs of a driver if you have a a small amount of test gear and patience.

This and five minutes is all you need. https://www.parts-express.com/Dayton-Audio-DATS-V3-Computer-Based-Audio-Component-Test-System-390-807?quantity=1

3 hours ago, DGBass said:

I'll assume Trace Elliot knew what they were doing at the time as the cab and speaker came as a package🙂 

Having seen some real nightmares I never assume that anyone knew what they were doing without checking it for myself. 😉

By and large most fifteens work best with cab tuning of 45-50Hz. That can be confirmed from the cab dimensions alone.

A hole is a port. A hole with a tube or extension behind it is a ducted port. Over the decades the 'ducted' part of the name has been dropped from common usage. A hole is still technically a ducted port, with the duct length being the thickness of the panel it goes through. The longer the duct the smaller the port will be and the smaller the cab may be for a given tuning frequency. The smaller the port the higher the velocity of the air vibrating within it. With sufficient velocity you can hear that air mass vibrating, so there is a point where it can be too small. Your cab may be fine, it may not, which can be determined with the exact cab dimensions and the driver specs.

58 minutes ago, greentext said:

 From memory built to revival the Ampeg's when Canada was no longer importing them?

They were actually Canada's Fender. They were fairly popular as a less expensive alternative to Fender back in the 60s-70s, especially in the states that bordered Ontario and Quebec. I bet thousands made the trip across the bridge that connects Windsor, Ontario with Detroit. Back in the day crossing the border entailed not much more than a wave at the agents, and no one paid much attention to what was in your car.

1 hour ago, BigRedX said:

It's a fact that identical cabs should give you a more consistent sound throughout the venue.

Far more often than not that's true. You can combine just about any two cabs and they'll sound better than either one on its own. That's because the two will be louder than one at the same amp setting, and louder is subjectively better. However, the only way one can know if X+Y works better than, or even as well as, X+X or Y+Y, is to try all three combinations side by side. In some twenty-five years of seeing these discussions I can't recall a single instance where someone actually did so.

Horizontal 210s, or horizontal any ten or twelve configuration, were originally created because valve amps were wide. It's not like the audio community didn't know that vertical was better. St. Paul's Cathedral in London was equipped with vertical arrays in 1949.  They were only recently upgraded, with new vertical arrays. http://www.pamphonic.co.uk/029_wireless_world_1952_St_Pauls.PDF

Now that amps are much narrower speaker manufacturers are finally making available what they should have in the first place.

I haven't come across the tweeter option at BF. I recommend the Eminence BGH25-8, in part because it rolls off above 10kHz, where there's no useful content. The other part is because with 4th order filtering it can be run down to 2kHz, where it gives much wider dispersion than a woofer can.