Adding additional cab

[Craigster]

Hi all, any advice please.

 

I have a 700w black star amp head and a Hartke 1000w 4 x 10 8 ohm cabinet.

 

I'd like to add an additional 1 x 15 or 1 x 12 ( 250 or 500w ) cabinet for increased low end.

 

Anyone know of a way to do the safely without affecting the impedance? 

Is there a gadget available to split the wattage across both cabs without blowing up the amp head?

 

Any advice would be amazing, thank you all.

 

 

[BigRedX]

Your amp should go down to 4Ω so another cab identical to the one you already have would be the best.

 

For modern cabs - anything made in the last 25 years driver cone size is about the least important factor when it comes to tone (it will affect volume which is why another 4 x 12 cab may be better than a 1 x 15 or 1 x 12). If the bass goes through the PA your choice of cabs has practically no influence on what the audience hears. If your rig is required to project into the audience mixing different driver sizes without using a crossover to separate the frequencies being fed to each cab will lead to an inconsistent sound in the venue - whilst it might sound great to you standing next to it, it will sound completely different out in the audience which is where it really matters.

[fretmeister]

Get another Hartke of the same model.

 

Bigger cone size = more bass just hasn't been true for decades.

But mixing cones (make and size) always leads to EQ compromises that you just don't need. The perfect EQ for the 4x10 will be different for any other cab.

 

So just get another of the same. It's almost always the best choice.

 

Then if you want more bass, approach it from the other way. Cut the treble / mids and work on the low end only, then add back the mids and treble.

 

 

[BassmanPaul]

The pairing of a 4x10 and a 1x15 is poor at best. Often it leads to the demise of the 15.

 

Thinking that a larger cone equates to more bass is antiquated thinking. The 4x10 is more than capable of putting out more lows than a single 12 or a 15.

[Downunderwonder]

Ditch the Hartke and grab the BF BigTwin in the classifieds.

[Chienmortbb]

You need to re-evaluate what you are trying to achieve. Make sure the sound you are after is one that will sit in the mix well. Lots of high-end does not.

[Lozz196]

Adding in the same cab again and keeping all eq the same in most cases sounds like a big addition on low end in my experience, as quite simply it’s doubling the sound. It makes it twice as big so it seems that there’s more low end.

[Downunderwonder]

If we use some typical figures your 410 should be around 101dB sensitivity and a 115 might be 97dB on a really good day.

 

Let's say they have similar rolloff in the lowest frequencies of interest.

 

Your amp might output 500W into the 410 and be on the edge of farting if you push it for lows.

 

Let's say you can find a 97dB 115 that can handle 350w similarly, ulikely though.

 

You are trading 150W less @ 101dB for 350w @ 97dB which is roughly a wash.

 

But now your 115 is maxed while your 410 is having an easier time of it. Tends to break the 15 because you don't hear it complaining over the racket of the 410 in your ear hole.

 

That racket sounds a hell of lot louder to you on stage but when push comes to shove it won't have more low end in it.

 

At less than max output it will sound like you have a lot more headroom than you actually have. This is even more of a problem when you are basing this on the loud knob position.

 

[Dan Dare]

A lot of good advice above. You aren't driving your 4x10 to anything like its potential with your current amp. A decent 4x10 can produce plenty of low end weight. A single 12 or 15 will likely struggle if you add it, as well as causing issues others refer to above. I'd be investigating a more powerful head to get the most out of the 4x10. 

[Downunderwonder]

3 hours ago, Dan Dare said:

I'd be investigating a more powerful head to get the most out of the 4x10. 

I wouldn't. Too many fudgy numbers flying around which means more power is almost never the answer....

 

1000w is a pipe dream cab rating, and OP is looking at the low end response where the rubber hits the road.

 

Class D amps usually get a notable bit over half of the rated output when pushing 8 ohms.

 

700w could easily be pumping out 500w thumps. I reckon he's pretty darn good for power.

 

To make an appreciable difference the cab would need an actual thousand watts up it, and that would break it.

[Bill Fitzmaurice]

2 hours ago, Downunderwonder said:

1000w is a pipe dream cab rating

Agreed. It may very well handle 1000w thermal, but probably can't take more than half that mechanical. If the OP can't get enough volume with that cab it's not a matter of having more power, it's a matter of having higher sensitivity. A second cab will give that, but anything other than an identical second cab is a crapshoot at best.

[Dan Dare]

20 hours ago, Downunderwonder said:

I wouldn't. Too many fudgy numbers flying around which means more power is almost never the answer....

 

1000w is a pipe dream cab rating, and OP is looking at the low end response where the rubber hits the road.

 

Class D amps usually get a notable bit over half of the rated output when pushing 8 ohms.

 

700w could easily be pumping out 500w thumps. I reckon he's pretty darn good for power.

 

To make an appreciable difference the cab would need an actual thousand watts up it, and that would break it.

 

Perhaps, but as has been discussed extensively on here previously, wattage is a crude and not particularly accurate measure of what an amp can deliver. A 700w rated amp may deliver that in a one millisecond burst when connected to a test meter, but not into a reactive load like a speaker cab. That applies especially to some class D amps, which can be optimistically rated (no names, no pack drill, but the letters T&C spring to mind).

 

1000w isn't necessarily a pipe-dream cab rating. Barefaced rate their 2x12 cabs at up to 1200w and their 4x10 at 1000w and they are not known for exaggeration. It isn't at all unfeasible that a good quality 4x10 could safely handle 1000w.

 

The OP isn't asking for more absolute volume, but more low end weight. It's well-established that a more powerful amp will give a fatter sound, even at lower volumes.

[Downunderwonder]

Two things.

 

Hartke are not nearly in the same league as Barefaced.

 

A burst of low end is what busts up woofers.

[xgsjx]

You could always add a sub if you’re after the really low frequencies.

Also worth looking at the bass’ pickups, EQ & strings to see what could provide more lows too. 

[BassmanPaul]

18 hours ago, xgsjx said:

You could always add a sub if you’re after the really low frequencies.

Also worth looking at the bass’ pickups, EQ & strings to see what could provide more lows too. 

just for interest, what will a sub do for bass guitar.  The lowest note on a bass would be around 30Hz. That's above where a sub will typically operate.

[Bill Fitzmaurice]

The lowest fundamental on a low B bass is 31Hz, but there's very little content at 31Hz. It's mainly 2nd and 3rd harmonics. The fundamental content doesn't equal the loudness of the harmonics until you get up around the open D string. Most of what we perceive as low bass is actually midbass, from 60 to 100Hz. One reason why bass can sound really bad through large PA is when a cretin at the FOH desk boosts the content below 60Hz. IME the best FOH mixers tend to be adept studio mixdown engineers and/or bass players. They'll usually high pass the bass channel strip at 60Hz, to account for the difference in how the bass sounds through bass speakers as opposed to giant PA subs.

On the range of subs they're usually run from 30 to between 80 and 100Hz.

[xgsjx]

3 hours ago, BassmanPaul said:

just for interest, what will a sub do for bass guitar.  The lowest note on a bass would be around 30Hz. That's above where a sub will typically operate.

What BFM said. I considered building a BFM sub a while back to add to my 2x10, but life got in the way. 
I use a virtual rig & just DI to the PA. My plan is to get an RCF 915 to put my bass & synth through & the drummer has one too, so could use them for the full band & still add a BFM sub with an amp. 

[Dan Dare]

22 hours ago, Downunderwonder said:

Two things.

 

Hartke are not nearly in the same league as Barefaced.

 

A burst of low end is what busts up woofers.

 

Two more things.

 

Hartke is a reputable manufacturer. Perhaps not quite as sophisticated in its cabinet designs as BF, but better than many. Their drivers - hybrid and aluminium coned, for example - are quite innovative. They don't simply play the me-too game that so many do.

 

What really "busts up woofers" is feeding them a dirty, clipped signal from an amplifier that is struggling to deliver enough power because its power supply is inadequate. Reputable drivers can deal with short term transients of up to twice their rated constant power as long as the signal is clean and the cabinet they are mounted in is properly designed.

 

 

[Downunderwonder]

BFM will be along to correct you far more concisely than I could.

[Bill Fitzmaurice]

10 minutes ago, Dan Dare said:

 

What really "busts up woofers" is feeding them a dirty, clipped signal from an amplifier that is struggling to deliver enough power because its power supply is inadequate.

 

 

That's the Myth of Underpowering. Key word: Myth. Clipped signals can hurt tweeters by overpowering them. Woofers, never.

[Downunderwonder]

Barefaced unwittingly play into that myth.

 

You are told you can use X000 watts amp but you must be using a clean tone. That's so you can avert destruction by hearing it start to complain before you go too far. If it's distorting with a clean tone the woofer is being made to travel beyond where it is happy.

[Bill Fitzmaurice]

That's true, but...we run into that with horn loaded subs, which are so clean that they filter out harmonic distortion that warns of over-excursion. The cure is using a limiter, so that no matter how hot the amp input signal is it won't produce more voltage than the speaker can handle, either thermally or mechanically. Guitar amps routinely run with very high THD, and they use very short xmax woofers as well, so that clipping is produced by the speaker as well as the electronics. It bothers them as much as water does a duck. But they don't use tweeters, which wouldn't handle the high THD and would sound really bad as well. On that point if you've wondered why bass cab tweeters have an attrition rate that dwarfs that of woofers it's this, abnormal high frequency content that results from clipping anywhere in the signal chain, including pedals.

[Dan Dare]

2 hours ago, Downunderwonder said:

BFM will be along to correct you far more concisely than I could.

 

I always respect Bill's opinions. He knows his onions. Just as well for you, eh?

 

Now, about my other point, re Hartke and 1000w not being a "pipedream" rating. Let's hear your wisdom.

[Downunderwonder]

5 minutes ago, Dan Dare said:

Now, about my other point, re Hartke and 1000w not being a "pipedream" rating. Let's hear your wisdom.

Afaik no mainstream manufacturer uses 10" woofers with the kind of excursion capacity required to make good use of 250w each. They all do the thing of quoting thermal power handling per BFM's post.

 

If Hartke were the exception they would be selling like hotcakes and BF wouldn't get a look in.

[Downunderwonder]

On 11/05/2023 at 13:56, Bill Fitzmaurice said:

On 11/05/2023 at 11:01, Downunderwonder said:

1000w is a pipe dream cab rating

Agreed. It may very well handle 1000w thermal, but probably can't take more than half that mechanical

Exhibit B.