speaker efficiency for 1x12 cab and multiple amps

[Robert Parker]

I need some perspective on speaker efficiency, particularly for an Eminence speaker. I'm sure what I'm proposing will sound ridiculous, but humor me. I want to use the same 1x12 cab for both a low watt tube amp head and a 100w hybrid amp head (Marshall valvestate). Not at the same time, just interchangeably as needed.

I understand a higher efficiency speaker will give more volume/projection/etc. than a low efficiency one. I understand that changes in efficiency and volume produce a non-linear change (10dB is only twice as loud as 1dB, not 10x's as loud). I've read some information about speaker efficiency, volume, etc., but I'm still really uneducated in this area . So, I want to ask three questions:

1) Can a low watt amp (for argument, 5-6 watts such as a VHT Special 6 or Marshall Class 5) effectively drive a speaker that will also handle 100w from a more powerful amp? Will it give good sound quality (I know, I know - that's subjective)?

2) What other specs (besides dB rating) do I look at to gauge efficiency?

2) If so, got any good recommendations? I'm leaning toward Eminence because of their reputation and relative affordability. Other suggestions?

 

[Rhust]

I need some perspective on speaker efficiency, particularly for an Eminence speaker. I'm sure what I'm proposing will sound ridiculous, but humor me. I want to use the same 1x12 cab for both a low watt tube amp head and a 100w hybrid amp head (Marshall valvestate). Not at the same time, just interchangeably as needed.

I understand a higher efficiency speaker will give more volume/projection/etc. than a low efficiency one. I understand that changes in efficiency and volume produce a non-linear change (10dB is only twice as loud as 1dB, not 10x's as loud). I've read some information about speaker efficiency, volume, etc., but I'm still really uneducated in this area . So, I want to ask three questions:

1) Can a low watt amp (for argument, 5-6 watts such as a VHT Special 6 or Marshall Class 5) effectively drive a speaker that will also handle 100w from a more powerful amp? Will it give good sound quality (I know, I know - that's subjective)?

yes, no problem... I have 2 200w peavey scorpions in my 2x12 cab... I use one of them for my HT5(8 ohm) or wire my cab for 4 ohm for my tremolux... but even a 1 watt amp could push them enough... wattage is a maximum... not a minimum... you do need to make sure that if say you build a cab as 8ohm, that both amps can use a single 8 ohm load...

2) What other specs (besides dB rating) do I look at to gauge efficiency?

look at a figure called "sensitivity" this is how loud the speaker is when pushed by 1 watt of power at 1 meter... >100 is pretty efficient. sometimes you go for less efficient on purpose, to lower the volume...

2) If so, got any good recommendations? I'm leaning toward Eminence because of their reputation and relative affordability. Other suggestions?

nothing wrong with eminence... they have a wide range, and they also demo their speakers well on their website... they aren't usually much cheaper than celestions, or weber, or WGS or scumback, really.. hit ebay, too... some people sell relatively low-usage celestion/eminence for cheap...

believe it or not, many peavey branded speakers are quite good... I've used my scorpions for a long time, they are a neutral, moderate speaker... they don't color the tone of the amp, making them good for multiple amps... idk who makes peavey's speakers before they slap a peavey sticker on them...

some speakers color the sound of the amp, maybe they have looser bass characteristics, or really tight highs... sometimes you have to play around with speakers to get what matches your amp... for that 'best' sound you hear in your head

 

[cybermgk]

I'll add the following. Speaker efficiency and power rating are seperate entities. Also, perhaps think about other than a 1x12. Reason you don;'t see a lot of 100w heads running through 1x12 CABs, is there are not a lot of speaker choices to handle 100w amps (quite a few other reasons, but this is a factor). If it is tube output, and thus subject to tube clipping, you really want your Speaker(s) rated for 200W. Limits the field for 1x12. Multiple speakers, its basically #speakers in cab x Watt Rating for lowest rated speaker. So to get 200w, a 2x12 can run two 100w apeakers, a 4x12, 4 50w speakers, or all speakers at 50w or above.

 

[Rhust]

true statement... amp wattage is usually RMS... constant power.... speakers usually list as peak wattage... so a 100w amp, actually has a peak that is quite a bit higher, especially on tube.... so you need a speaker that CAN hold more...

the valestate is a solid state power section IIRC, not hitting the speakers nearly as hard as 100w tube amp, but I think you would still want a cab that can hold at least 150-200w

 

[dspelman]

I need some perspective on speaker efficiency, particularly for an Eminence speaker. I'm sure what I'm proposing will sound ridiculous, but humor me. I want to use the same 1x12 cab for both a low watt tube amp head and a 100w hybrid amp head (Marshall valvestate). Not at the same time, just interchangeably as needed.

I understand a higher efficiency speaker will give more volume/projection/etc. than a low efficiency one. I understand that changes in efficiency and volume produce a non-linear change (10dB is only twice as loud as 1dB, not 10x's as loud). I've read some information about speaker efficiency, volume, etc., but I'm still really uneducated in this area . So, I want to ask three questions:

1) Can a low watt amp (for argument, 5-6 watts such as a VHT Special 6 or Marshall Class 5) effectively drive a speaker that will also handle 100w from a more powerful amp? Will it give good sound quality (I know, I know - that's subjective)?

2) What other specs (besides dB rating) do I look at to gauge efficiency?

2) If so, got any good recommendations? I'm leaning toward Eminence because of their reputation and relative affordability. Other suggestions?

The efficiency rating (say, 100 dB, 1W/1M) will tell you how much volume you're going to get for a given number of watts. What it's telling you is that if you put 1W into the speaker and then measure it at 1 Meter, you should get 100 dB. Multiply that 1W to 2W and you gain 3 dB. from 2W to 4W, another 3 dB. From 4W to 8W, another 3 dB, so an 8W amp should give you around 109 dB. Keep going to 16W, then 32W, then 64W and you'll add another 9 dB. 100W amps will often put out about 120 dB with a speaker and cabinet combination that will give you around 100 dB efficiency. One caveat, however. That measurement (for guitar speakers) is usually done at 1000Hz. Requirements (and efficiency) at other frequencies can be quite different.

If you get a speaker capable of handling 100W, it will also sound pretty much the same with 5W. Just...quieter. An Eminence Delta ProA, for example, will typically handle up to 400W but will maintain the same efficiency throughout its power handling range.