Jump to content
bass_ferret

Impedance etc

Recommended Posts

[quote name='StraightSix' timestamp='1342811224' post='1741463']
Maximum of 750 watts RMS running at 4 ohms.
[/quote]

So the sum of both cabs wattage then?
That's the same as my current 412 cab, will they feel as loud by being two cabs?

Share this post


Link to post
Share on other sites

I would suggest you should exercise caution with those cabs - most cab wattage ratings are based on thermal limits of the speaker voice coils.

This means that they will overheat at approximately the RMS rating but many bass speakers will hit their excursion (movement) limits well before that and be damaged.

As to similar volume levels to your 412, you will have to compare them to know for sure.

Share this post


Link to post
Share on other sites

[quote name='BigAlonBass' timestamp='1342736930' post='1740384']
Here's a (probably) silly question:- I have a Peavey Max 700 Amp with 2 speaker outputs. I have 2 x 8 ohm cabs and 1 x 4 ohm cab. If I 'daisy chain' the two 8 ohm cabs to one output, and the 4 ohm cab to the other output, is it delivering 4 ohms through each output?
[/quote]

The two outputs are probably connected in parallel, so you'll actually finish up with a load of 2 ohms.

Share this post


Link to post
Share on other sites

[quote name='PauBass' timestamp='1342811347' post='1741466']
So the sum of both cabs wattage then?
That's the same as my current 412 cab, will they feel as loud by being two cabs?
[/quote]

No, not the sum of the two cabs wattage. The two cabs will have a total impedance of 4 ohms, the DB750 will output 750W into 4 ohms, 375W into each cab. However, unless you make a habit of running the amp flat out constantly, the fact that it can nominally output 25W more than the rated power into one of the cabs should be irrelevant.

Share this post


Link to post
Share on other sites

Tauzero, StraightSix, thanks a lot for your help guys!

Not sure if changing my 412 cab rated at 750 watt is going to be a good idea, with the new rig I'll be losing one speaker as I'll have a 115 and a 210 cab...will I
lose volume?

Edited by PauBass

Share this post


Link to post
Share on other sites

[quote name='PauBass' timestamp='1342818991' post='1741620']
Not sure if changing my 412 cab rated at 750 watt is going to be a good idea, with the new rig I'll be losing one speaker as I'll have a 115 and a 210 cab...will I
lose volume?
[/quote]

Hmmm, how long is the piece of string that you use to tie up your apples and oranges?

Speakers differ in efficiency as well as in impedance and power handling. Total speaker cone area will be smaller but if the speakers move further (higher Xmax) then the volume of air moved might be the same or more.

How often do you actually run it flat out?

Share this post


Link to post
Share on other sites

[quote name='tauzero' timestamp='1342819786' post='1741633']


....Speakers differ in efficiency as well as in impedance and power handling. Total speaker cone area will be smaller but if the speakers move further (higher Xmax) then the volume of air moved might be the same or more.

How often do you actually run it flat out?
[/quote]

Well I do play in a very loud rock band and I need the power/volume for this gig.
The cab I'm thinking of replacing is a Bergantino NV412, just because I want to make the rig a bit more portable for smaller venues.

Share this post


Link to post
Share on other sites

[quote name='PauBass' timestamp='1342865400' post='1741971']
Well I do play in a very loud rock band and I need the power/volume for this gig.
The cab I'm thinking of replacing is a Bergantino NV412, just because I want to make the rig a bit more portable for smaller venues.
[/quote]

The Berg outputs a sound level of 103dB at 1W at an ear located 1m from the speaker (if Berg's figures are to be believed). What you need to do is find the SPL for the other two speakers. Things start getting rather convoluted due to the logarithmic nature of sound levels, but, taking a simplistic approach, if they're both around the 103dB 1W/1m level, the volume will be around the same. A 3dB difference in sound level means a doubling in power, so if they were both around the 100dB level, you would need to turn the amp up a bit. How much is another of those piece of string questions, volume/output level controls are nominally logarithmic so on a scale of 1 to 10 you might turn it from 5 to 6, or you might have one of the more biassed controls that have most of the power increase over the first half of their travel which would mean you had to go from (say) 4 to 8.

There may well be someone a bit more knowledgeable than me along in a bit to correct any mistakes I've made.

Share this post


Link to post
Share on other sites

[quote name='tauzero' timestamp='1342880138' post='1742311']
The Berg outputs a sound level of 103dB at 1W at an ear located 1m from the speaker (if Berg's figures are to be believed). What you need to do is find the SPL for the other two speakers. Things start getting rather convoluted due to the logarithmic nature of sound levels, but, taking a simplistic approach, if they're both around the 103dB 1W/1m level, the volume will be around the same. A 3dB difference in sound level means a doubling in power, so if they were both around the 100dB level, you would need to turn the amp up a bit. How much is another of those piece of string questions, volume/output level controls are nominally logarithmic so on a scale of 1 to 10 you might turn it from 5 to 6, or you might have one of the more biassed controls that have most of the power increase over the first half of their travel which would mean you had to go from (say) 4 to 8.

There may well be someone a bit more knowledgeable than me along in a bit to correct any mistakes I've made.
[/quote]

Thanks again for your advice...I've found out they they output at and I assume there's going to be a bit of a drop in volume there:

[b]Sensitivity:[/b][color=#000000][font=Arial, Helvetica, sans-serif][size=3] 96 dB 1W 1M For the 115 cab[/size][/font][/color]
[b]Sensitivity:[/b][color=#000000][font=Arial, Helvetica, sans-serif][size=3] 98 dB 1W 1M for the 210 cab[/size][/font][/color]

Share this post


Link to post
Share on other sites

I think you may need to look for another alternative - EAD Foundation 212, Tech Soundsystems ND212 or ND410 perhaps.

Share this post


Link to post
Share on other sites

Hi I have just bought a Markkbass Little Mark Tube head rated at 300W RMS @ 8 ohm, 500W RMS @ 4 ohm and a Markbass Traveler 102P 4 ohm 2x10 does this mean I can not at a later stage add a second cab as if I add another 4 ohm cab that will make it 2 ohms which means I should have bought the 8 ohm cab. Please advise as I do not want to damage the head?

Edited by alan_01_uk

Share this post


Link to post
Share on other sites

[quote name='alan_01_uk' timestamp='1346584183' post='1790749']
does this mean I can not at a later stage add a second cab[/quote]

Yes - you can use two 8 ohm cabs or just one 4 ohm cab with that amp.

Edited by StraightSix

Share this post


Link to post
Share on other sites

[quote name='StraightSix' timestamp='1346584764' post='1790765']
Yes - you can use two 8 ohm cabs or just one 4 ohm cab with that amp.
[/quote]

Thanks for the reply but that is my point I would have to buy two more 8 ohm cabs as if I had bought the 2x10 8 ohm cab I would have just had to buy the 1x15 8 ohm cab so I can't use the 2x10 cab I have got and just add another cab I will have to buy another two 8 ohm cabs?

Share this post


Link to post
Share on other sites

[quote name='alan_01_uk' timestamp='1346585472' post='1790781']
Thanks for the reply but that is my point I would have to buy two more 8 ohm cabs as if I had bought the 2x10 8 ohm cab I would have just had to buy the 1x15 8 ohm cab so I can't use the 2x10 cab I have got and just add another cab I will have to buy another two 8 ohm cabs?
[/quote]

I'd sell (or take back to shop & exchange) the 4Ω cab & get the 8Ω 2x10 & then you can add another 8Ω 2x10 when needed (or any other 8Ω cab).
With your amp the most you can use is 1 4Ω cab or 2 8Ω cabs (or 4 16Ω cabs).

Share this post


Link to post
Share on other sites

[quote name='xgsjx' timestamp='1346588670' post='1790833']
I'd sell (or take back to shop & exchange) the 4Ω cab & get the 8Ω 2x10 & then you can add another 8Ω 2x10 when needed (or any other 8Ω cab).
With your amp the most you can use is 1 4Ω cab or 2 8Ω cabs (or 4 16Ω cabs).
[/quote]

That is what I thought thanks for your advise. Anyone out there would like to interested in swapping there markbass 102p 2x10 8 ohm for my 4 ohm pm me.Thanks Alan.

Share this post


Link to post
Share on other sites

How long have you had your cab? Might be worth having a word with where you bought it if recent.

Share this post


Link to post
Share on other sites

I have just bought it but the guy I got it from bought it about 10 months ago to learn to play never gigged but decided bass is not for him so only been used in his bedroom so can't exchange.

Share this post


Link to post
Share on other sites

You'd probably be as well to just hold on to it & sell or swap it if you get to a point where you need to.

Share this post


Link to post
Share on other sites

That is what I think I will do. I will only be doing duo gigs with this and I di through the pa. When I do a band gig I use my dynacord reference 3000 4x10 300 watt combo.

Share this post


Link to post
Share on other sites

You should give the MB rig a try in your full band. You might be well surprised.

Share this post


Link to post
Share on other sites

[quote name='xgsjx' timestamp='1346594215' post='1790930']
You should give the MB rig a try in your full band. You might be well surprised.
[/quote]

Ok thanks for the advise I am doing a small venue with the band next Saturday I will give it a try and let you know how it goes.

Share this post


Link to post
Share on other sites

[quote name='xgsjx' timestamp='1346594215' post='1790930']
You should give the MB rig a try in your full band. You might be well surprised.
[/quote]

Thanks for your advise I played in a medium sized pub last night with the band and I have only ever used the markbass for my duo gigs where I di through the pa and it really worked well and the band were well surprised and it means when I am playing a small to medium venue I will not have to break my back and take my Dynacord 4 x 10 300 watt combo.

Share this post


Link to post
Share on other sites

[quote name='alan_01_uk' timestamp='1347193357' post='1797840']
Thanks for your advise I played in a medium sized pub last night with the band and I have only ever used the markbass for my duo gigs where I di through the pa and it really worked well and the band were well surprised and it means when I am playing a small to medium venue I will not have to break my back and take my Dynacord 4 x 10 300 watt combo.
[/quote]

Might be worth considering selling the 2x10 & the combo & getting a couple of 8Ω 2x10s?
Did you stick the 2x10 vertical?

Share this post


Link to post
Share on other sites

[quote name='xgsjx' timestamp='1347195192' post='1797866']
Might be worth considering selling the 2x10 & the combo & getting a couple of 8Ω 2x10s?
Did you stick the 2x10 vertical?
[/quote]

Yes I did have it vertical so the speakers would be one on top off the other rather than next to one another is that a good or bad idea?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.



×
×
  • Create New...