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Fingers McGee

Help needed to understand Ohms with split bass cab

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Hi all

This is my first time posting but I need some help and advice

im looking to upgrade my current set up from a combi bass amp to a 2 cab and amp head set up. This is largely due to the gigs I now do mean I play straight from the amp, whilst guitars and vocals go over the PA

ive been looking at what to get and I’ve decided to get a 4x10 cab with a 1x15 cab and a 900w amp head. My current amp is 450w and the issue I have is that the volume is lost when I play at most venues, pass the first few people. I believe this is due to the amp wattage and that it sits on the floor

looking at the split cabs I don’t fully understand the ohms part. The new 4x10 has 650w output and the 1x15 has a 300w output. The head is 900w and supports a minimum of 4ohms

i thought that more watts equals more volume. How does that translate to the ohms part. Can anyone help?

btw, the cabs state they’re 8ohms

thanks

Dave

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Posted (edited)

 

If you want 900 watts you don't need big gear any more, but you need the flexibility. Adding more cabs will get you much louder than increasing the number of watts. .

Big amps are fine but more flexible if they go to 2.67 ohm. That means you can run 3 8 ohm cabs or 1 4 ohm and 1 8 ohm cab.

 

Edited by chris_b

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Posted (edited)

In terms of your gear @Fingers McGee, a 900 watt head at 4 ohms will put 450 watts into each 8ohm cab. So in theory the 410 will be fine, the 115 less so. But in practice if you`re running that rig to the point where the 115 blows, your ear-drums will more than likely have bled dry by that point, so you should be fine with it.

That said I`d be more likely to get two of the 410s, or a 410 and 210. If they`re from the same brand & range they`ll more than likely be voiced similarly, whereas a 115 will probably be voiced differently, meaning your sound will be made of two different sounding cabs, so you`ll always need the two to get it. The benefit of 2 x 410 or a 410 & 210 is that for smaller gigs/practices you can use just the 410 and only bring out the other cab for the bigger gigs.

And, moving on from that, I have a 600 watt amp with 410 & 210 cabs and have never actually needed the 210. You may well find that the 900 watt head into the 650 watt 410 will be plenty enough.

Edited by Lozz196

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41 minutes ago, Fingers McGee said:

 I’ve decided to get a 4x10 cab with a 1x15 cab
 

That's not a good idea. 1x15s don't necessarily go lower than 4x10s, 4x10s don't necessarily go higher than 1x15s. Even if they did power handing requirements go up as frequency goes down, so in this scenario the 115 is the weak link in the chain.

Quote

the issue I have is that the volume is lost when I play at most venues, pass the first few people. I believe this is due to the amp wattage and that it sits on the floor

Not true, on both counts.

Quote

The new 4x10 has 650w output and the 1x15 has a 300w output.

Cabs don't output watts, they output sound pressure, measured in decibels. There's no direct correlation between the electrical power handling capacity of a speaker and its decibel output.

Quote

thought that more watts equals more volume

True, but that's not how you want to get more volume. For twice the volume it takes ten times the power. For that reason alone you need to get past watts, and learn about what really matters.  The technical information on the Barefaced site is a good starting place.

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Cheers for the comments guys. Really appreciated. This is my first foray into the realm of separate cabs so this is all new to me and my knowledge is pretty limited, at best!

so it sounds like the 1x15 isn’t the best way to go (the 4x10 and 1x15 was the set up recommended to me in the music store). So I’ll have a look at a 2x10 instead (maybe even another 4x10 if I’m feeling flush!)

any other recommendations or considerations I need? Would a 600w head be better, if I went for the 1x15. Reason I ask is our PA is 800w (I think) so would having these 2 cabs and a smaller 600w head be enough?

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Which heads and cabs are you looking at?  I.e. the make & model.  Because things vary a lot between brands. For example, a brand new Harley Benton BB115T and five-year-old Barefaced Compact are both "1x15 cabs", but the Barefaced would completely destroy the other (and weigh half as much).

Similarly, what was the make & model of your previous combo, so we know where you're coming from?  The more information we have, the specific and better the advice can become.  (The advice has been good so far btw!)  Budget, musical style, and type of venue are also useful to know.

Can the bass be put through the PA; and if not currently, can the PA be upgraded?  Because then things might sound better to the audience, and you could use a smaller amp on stage.  Some bands using good PAs might not even have a bass amp at all.
 

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35 minutes ago, Fingers McGee said:

any other recommendations or considerations I need? Would a 600w head be better, if I went for the 1x15. Reason I ask is our PA is 800w (I think) so would having these 2 cabs and a smaller 600w head be enough?

I've never run more than 200w, and seldom more than one cab. Your amp's job is to carry the stage, carrying the room is the PA's job. That's where you should be considering an upgrade.

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I’m currently using an Ampeg BA210; 2x10 speakers and a tweeter

im looking at and Ashdown set comprised of:

- Ashdown ABM-115H Compact EVO IV

- Ashdown ABM 410H 4x10

- Ashdown ABM 900 EVO III

Im in 2 bands: 1 does original and the other does covers for weddings etc. It’s the covers band that usually gets more gigs (other band is usually at proper venues with a proper PA)

our current PA, for the covers band, doesn’t have any bass bins to push the bass through. This band plays small venues usually; maybe between 50 - 100 people, if that

 

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32 minutes ago, Fingers McGee said:

This band plays small venues usually; maybe between 50 - 100 people, if that

 

I'd have no problem with 200w and a 1x12 with no PA for that gig. You really need that much kit for a wedding band? Who are you covering? Sabbath?

  • Haha 2

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Posted (edited)

I played in a wedding band for many years and the the problem venues were those in marquees. Roughly half your sound energy disappears out through the canvas and you definitely miss the backwall reflection and room reverb. As is often said on here, doubling up on cabs is probably more important than absolute amp power, within reason (the Shuttle 6.2 claimed 600 Watts into 4 Ohms). I used Genz Benz gear and a couple of 12" cabs did the job (edit:) in a marquee , or GB’s 2 x 10" cab when I was stuck for space in the car. Most of the time one 12” cab was plenty. 

Edited by DBerriff

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6 hours ago, Fingers McGee said:

I’m currently using an Ampeg BA210; 2x10 speakers and a tweeter

im looking at and Ashdown set comprised of:

- Ashdown ABM-115H Compact EVO IV

- Ashdown ABM 410H 4x10

- Ashdown ABM 900 EVO III

Im in 2 bands: 1 does original and the other does covers for weddings etc. It’s the covers band that usually gets more gigs (other band is usually at proper venues with a proper PA)

our current PA, for the covers band, doesn’t have any bass bins to push the bass through. This band plays small venues usually; maybe between 50 - 100 people, if that

 

I use an Ashdown ABM 600, into an Ashdown ABM 410, so probably getting 350/375 watts. The majority of my gigs are on big stages with everything going through the PA, it`s plenty for those stages never had to push volume, but in pubs etc this set-up is more than enough on its own without PA assistance. For reference I play in a punk band, so we`re not quiet. That Ashdown 900 head and the 410 will be plenty for the gigs you describe and being Ashdown the gear itself is pretty indestructible, and they offer excellent customer service too - they`re on here.

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6 hours ago, Bill Fitzmaurice said:

I'd have no problem with 200w and a 1x12 with no PA for that gig. You really need that much kit for a wedding band? Who are you covering? Sabbath?

This.

 

I play in a 25 piece big band with a load of noisy brass players.

 

I often use a 300W Tecamp head and a single Barefaced One10.

 

I only take the second cab when the audience numbers get to about 200. And even then it's for a better spread rather than volume.

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So you're using a 450 watt 210 combo without extension cab. That's about 250 watts into 210's. The 210 extension cab will give you a serious boost in volume and tone, but I reckon you can do better.

How are you sourcing the gear you've mentioned? I see the amp is discontinued. You're looking at big, heavy stuff. Is that intentional? What is your budget? 

If it has to be Ashdown, then Lozz196's suggestions are pretty spot on.

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On ‎08‎/‎08‎/‎2018 at 15:16, Fingers McGee said:

Hi all

This is my first time posting but I need some help and advice

im looking to upgrade my current set up from a combi bass amp to a 2 cab and amp head set up. This is largely due to the gigs I now do mean I play straight from the amp, whilst guitars and vocals go over the PA

ive been looking at what to get and I’ve decided to get a 4x10 cab with a 1x15 cab and a 900w amp head. My current amp is 450w and the issue I have is that the volume is lost when I play at most venues, pass the first few people. I believe this is due to the amp wattage and that it sits on the floor

looking at the split cabs I don’t fully understand the ohms part. The new 4x10 has 650w output and the 1x15 has a 300w output. The head is 900w and supports a minimum of 4ohms

i thought that more watts equals more volume. How does that translate to the ohms part. Can anyone help?

btw, the cabs state they’re 8ohms

thanks

Dave

Hi Dave, welcome to BC,

I'm pleased to see common sense is prevailing, you really don't need a 4x10, 1x15 combination. That sort of set up is very much old tech from the days when amps were costly and speakers of limited ability. The only reason to choose that sort of set up now is if you love the old school sounds or for the look a huge rig brings. All you really need to be able to do is match the drummer for volume. After all if the drums aren't going through the PA then you being much louder than that isn't going to give you a good sound anyway. If you are playing to 50-100 people then you will be more than loud enough. A modern 2x10 or even 1x12 will just about get you there in terms of matching the drums. I too use 1x12's, a single speaker for small venues and two for bigger or trickier venues like a marquee. My amps are both of the 300W into 8ohms 500 into 4ohms varieties.

If you are struggling to hear yourself then  it may be because of it's positioning. Being on the ground will reinforce the bass but it means the speaker isn't pointing at your ears so you miss a lot of the mid and high frequencies, if you can lean it back at an angle you will hear more. It may be your eq, at home most of us prefer a bass heavy mid scooped sound. Playing live you probably need to roll off the bass and boost the mids so you cut through to the audience, it sounds better that way with a live band too.

You don't say which combo you use or whether you like the way it sounds. Someone has already said it but if it is an 8ohm system then adding a matching 2x10 if that is possible will mean your amp will develop it's full power and the extra speakers will double the efficiency giving you an extra 6dB of sound, putting your combo on top of the extension speaker will raise the speakers nearer your ears. You'll be amazed at how much more authoritative that sounds. The sound you have now but bigger.

The ohms bit is simple enough, always use speakers of the same impedance, generally go for two 8ohm speakers, 16's won't draw full power from a solid state amp and two 4's are too low a load for most amps. Two 8's in parallel will nearly double the power the amp will give and that will be shared equally between speakers with the same ohms. As Lozz pointed out that's 450W per speaker with the amp you are wanting to use.. Matching amps and speakers isn't an exact science, their wattage ratings are done very differently, but using a 450W amp into a 300W speaker increases the possibility of damaging your speaker by pushing it too hard.

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At the cheapest end of the spectrum, I'd second the suggestion to have a play with your EQ in a band context - the mids is where you could have a look: a pleasantly scooped sound might be nice soloed at home, but might not work in a band context. Have a listen to some soloed bass tracks on YouTube to hear how different the big boys (Geddy Lee, tho he may not be your bag tone or music-wise, is a good example of this) sound without the band playing - it's always harsher on its own, but sits in the mix* much better.

On the power/speakers front, I'm in a similar position, playing in a busy function/covers band, and a Rawk band. We've gone in-ears/DI with the busier band (less humping and shifting backline down fire escapes at 1:30am), but even in the Old School Rawk band, I use a 300w head and an efficient 2x12, and I can more than compete with 2 100w Marshalls/4x12 playing at being Guitar Heroes, and the Gorilla from the Cadburys advert on drums. My criteria for backline is the unmiked kit: if I can compete/be heard with the unmiked kit (maybe some kick in the PA), then I have enough backline - if the kit starts to go through the PA, then I will, too. Guitars/keyboards should level to this, I should never get into a contest with them, because nobody ever thinks to attenuate, it's always 'turn up', and we'll be too loud for most venues and certainly my ears. I have the t-shirt (tinnitus) from years of doing this wrong. HTH... 🙂

 

* It might be just me, but this 'cutting through the mix' thing always confuses me - it's supposed to be a band sound, the mix is supposed to be that: a mix. I digress...

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Everything above is real common sense and very wise. A spec that you must know is the real sound pressure level of the cab you want to buy, because an increase of 3 dB's means doubling the output power. Try to find a second hand Schroeder cabinet rated at 4 Ohms to match the Ashdown head you wish to buy. Those cabs have a real high efficiency around 104 dB's when most of the other manufacturers are around 95 dB's... meaning at least 4 times less output power.

http://www.schroedercabinets.com/cabinets.html#cabmini8l

Why don't you run through the PA ?

We have a Bose L1 PA for years playing for weddings, restaurants, parties and it's just perfect (I simply add a small bass combo with a heavy mid sound for my personal comfort when needed).

https://www.thomann.de/gb/bose_column_systems.html

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Posted (edited)

Yep, and Schroeder cabs (especially the angled-speaker ones) are heavy in the mids and low-mids: it was this cab I was thinking of specifically when I mentioned boosting mids onstage...not  the prettiest-sounding cab soloed, but very useful in a band context...

Edited by Muzz

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Posted (edited)

I'm totally onboard with the above suggestions, a smaller, higher quality rig will undoubtedly be louder (when required), easier to move, etc etc.

 

But...

 

The Ampeg combo has an extension speaker out. If you really just want more volume, and a very swanky looking stand to get your combo up higher then why not look at an 8R extension cab to sit under the combo? You like the combo, it's familiar, and it works. It occurs to me that you could get an older, heavier extension cab now for very cheap and under your combo that would be a very formidable rig. Then, when and if you feel like it, you can get a discreet head and build a 'proper' rig piecemeal and as budget allows.

 

I'd go for an Ashdown 4x10" if I was you. It's perhaps not ideal to go under your combo this second (although it'll work just fine) but you seem to like Ashdown, and you can buy a matching head when you want to. They're also SUPER cheap.

Edited by Jack

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Thanks for the advice everyone. It seems that I might be focusing on the wrong area and need to consider using our PA more. My worry is that I could blow the speakers up as we only have 2 speakers on stands, we don’t have any bass bins on the floor (currently, the drums are not mic’d up either). This was based upon some advice a sound engineer gave me years ago - putting the bass through the speakers youbpce on stands could blow up the speaker. Is this correct?

 

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An additional 210 (8ohm) as already suggested seems like the way to go. I’m not familiar with your combo but sounds like it supports an 8 ohm extension cab and as mentioned your Output will roughly double. This is also likely to be the most cost effective way.

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31 minutes ago, Fingers McGee said:

Thanks for the advice everyone. It seems that I might be focusing on the wrong area and need to consider using our PA more. My worry is that I could blow the speakers up as we only have 2 speakers on stands, we don’t have any bass bins on the floor (currently, the drums are not mic’d up either). This was based upon some advice a sound engineer gave me years ago - putting the bass through the speakers youbpce on stands could blow up the speaker. Is this correct?

 

It's not going to blow them up, but they'll sound really bad. You, which means the band, need to invest in a good PA. The lack of it hurts all of you.

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There are still people labouring under the misapprehension that unless you run a 4x10 on top of a 1x15, you won't cover the whole frequency spectrum. It's really not necessary, but it does result in lots of cab sales!

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Just a though on the "cutting through the mix" point which has been touched on in a few posts. What EQ are you using on the bass and amp? there are plenty of threads on this topic but start with flat on both bass and amp. You might need to boost the mids to sit better in the mix. Also what EQ is your guitarist using? too much bass (and volume) will render the rest of the band inaudible!!

N

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You've already got solid advice, but I'll agree that if you like the sound of your combo then there's no reason to change it. Right now your output is 280W at 8 ohm. You can add another 8 ohm cabinet (a 4 ohm would not be safe with your amp, as it will bring the total impedence down to 2.67 ohm). Ideally you want the same wattage going to each speaker, so another 210 will bring the amp output to 450W and double the speaker area, giving you a good bump in volume, although a 410 should also work fine. But yeah, try boosting your mids first and consider the PA path too.

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Thanks everyone. Was a bit nervous with it being my first post, but I’m really great full for the sound advice and for everyone going easy on me :):)

So I’ll need to have a chat with the guys in the band as we joint own the PA, but I’m still thinking of updating my rig. I’ve had the Ampeg for around 10yrs, although I love the sound of the amp. I also really like the sound of Ashdowns And they’re in my price range. So, with that being said, what would be your recommendations on the following gear: 

- Ashdown ABM EVO IV 600 Watt Bass Amplifier Head 

- Ashdown ABM 900 Watt EVO III Bass Anplifier Head

both these heads are the same price, but the 600w is a newer spec

speakers:

- Ashdown ABM 410H 4x10 Bass Cab

- Ashdown ABM-210H 300w 2x10 Compact Bass Ca

- Ashdown ABM-115H Compact EVO IV Bass Cabinet 

so, for example, would the 600w head, combined with the 2x10 cab and 1x15 can be best, or would the 900w and 4x10 cab be the way to go? From what I understand of everyone’s comments, doing something like the 2x10, 1x15 and 900w would be a no go as I would be pushing too much through that set up

whats everyone’s thoughts, please?

 

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