@ Keriwena:
It just isn't that simple, go look at the impedance plot a few posts back, it tells you everything you need to know. This is essentially a 5 ohm speaker based on IEC criteria..
Bi-wiring simply separates the two halves of the X-O through some number of feet of wire where they rejoin at the amplifier output. In any event these speakers could have a 4 ohm woofer, and a 4 or even 8 ohm tweeter... The sum of the two X-O sections will be more or less identical (ignoring the small dcr of the speaker cables) regardless of whether they are bi-wired or not.
What is probably most important is the speaker impedance at frequencies where the amplifier needs to deliver real power and that would typically be below 300Hz ~..
Too True.
The links are there to join the HF and LF sections of the speaker together.
OK, each half may have its own unique impedance, but the two halves joined together will exibit the 4-8 Ohm load that the amp is looking for.
If you were to measure the HF impedance you would probably get nonsensically high values, depending on the design of the speaker.
These are used for Bi-Amping or Bi-Wiring.
Some DISCO speakers on the other hand do have dual voice coils - I'm sure that is outside of this topic of conversation.
In the case of Bi-Wiring the connections are connected together, but at the amplifier end not the speaker end.
In the case of Bi-Amping - the LF section is not normally a problem, however advice should be sought with the HF amp as Valve amps don't like High Impedance loads .Well they love High Impedance Loads but not using standard Output Transformers.
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But that line of reasoning doesn't explain the 'Ohms: 4-8' designation, does it?
Y'all seem to be assuming some engineer created that spec, but I think it was some guy in marketing, or the doofus that laid out the graphics. I think it's wrong, hence the rationale behind it is wrong.
Highly likely that marketing was responsible for this, and one can imagine that it arose because of the habit of marking cheap receiver outputs the same way. Someone probably figured it would just reduce consumer confusion. (Based on my experience in consumer electronics this is not at all unlikely.)
Sure, the only problem is that this way of specifiying only helps consumers with no idea at all. Anyway, it's 99,99% of the target, so imho, it's fully ok.😉
It seems that with guys with no idea enough ( or with guys who know too much... ) it sadly increases confusion....
But we all should admit that this is a quite marginal issue.😛Now that the impedance issue should be clear enough, maybe we might have a nice talk about the power specs of these speakers... 😀
The line of reasoning that explains how the speaker is labelled is simply that speakers impedance varies with frequency. They have actually labelled the speaker correctly indicating the range that the impedance moves around, rather than saying "6 ohm nominal"
Eltax are being idiots here. It's 4 ohms. Sorry. 😀
4-8 ohms doesn't usefully describe that speaker at all! FWIW, it's obviously a bass reflex 4 ohm woofer from the double hump in the bass, with an 8 ohm tweeter and a crossover around 2 kHz. Bass reflex is also a difficult reactive load for an amp, since it exaggerates currents flowing at given voltage.
My Rotel RA-931 will comfortably drive speakers with a minimum impedance of 4 Ohms. Or you can even have 2 pairs of loudspeakers as long as they are each 8 ohms minimum.
The limitation is in keeping the output transistors in their safe operating area, and avoid second breakdown due to high current at high voltage. The setup is designed to pop a typically 4A fuse before any harm is done from overdriving on typically 35V rails. If I connected two pairs of these Eltax to my Amp and turned up the volume, it would probably go pop, perhaps catastrophically because fuses take a while to blow. Which is what you need to know here, and why Eltax should call them 4 ohms. 😎
4-8 ohms doesn't usefully describe that speaker at all! FWIW, it's obviously a bass reflex 4 ohm woofer from the double hump in the bass, with an 8 ohm tweeter and a crossover around 2 kHz. Bass reflex is also a difficult reactive load for an amp, since it exaggerates currents flowing at given voltage.
An externally hosted image should be here but it was not working when we last tested it.
My Rotel RA-931 will comfortably drive speakers with a minimum impedance of 4 Ohms. Or you can even have 2 pairs of loudspeakers as long as they are each 8 ohms minimum.
The limitation is in keeping the output transistors in their safe operating area, and avoid second breakdown due to high current at high voltage. The setup is designed to pop a typically 4A fuse before any harm is done from overdriving on typically 35V rails. If I connected two pairs of these Eltax to my Amp and turned up the volume, it would probably go pop, perhaps catastrophically because fuses take a while to blow. Which is what you need to know here, and why Eltax should call them 4 ohms. 😎
Looks to me like the range is more like 4 - 15 ohms, so I have trouble with that explanation and the contention it is correctly indicating anything.
Maybe, Eltax considers them 6 ohm monitors, and maybe someone pointed out that output transformers only have 4 and 8 ohm taps.... but I don't see these speakers being marketed to, or purchased by, valve heads.
The review the impedance graph came from is here:
Eltax Monitor III Bookshelf Loudspeakers | Hi-Fi
and in it they mention Eltax claims a frequency response of +/- 4, not the usual +/-3, and the sensitivity spec is overly optimistic. Also, all Eltax speakers are marked '4 - 8' ohms, suggesting they use the same terminal cups on all of them, not that the markings reference a particular speaker.
(I just saw what system 7 posted while I was busy typoing, and '4 ohm woofer - 8 ohm tweeter' may indeed be what they mean. But I agree, it's dumb.)
For all our criticisms of the Eltax Monitor III on specifications, it looks like pretty decent loudspeaker for a good solid state amp!
I've never liked these overly small speaker boxes, because they mostly LACK the bass. But fitting a biggish 55Hz 5" unit with a bass reflex seems to work here. 😎
What do you think of them, JammyBStard? Happy? 🙂
I've never liked these overly small speaker boxes, because they mostly LACK the bass. But fitting a biggish 55Hz 5" unit with a bass reflex seems to work here. 😎
What do you think of them, JammyBStard? Happy? 🙂
I've had them for years, they were about £60 from Richer-Sounds ten years ago; they've been sitting doing nothing on the shelf; I was just using them to test the new T-Amp and was shocked by how good they sound together. I was going to build a pair of my own but I'm so happy with them; I think it could be a fixture.
I had a look inside too and the buid quality and X-Over parts quality are all very good for the price. I bet you'd find loads on uk ebay if you were after a cheap set of decent book-shelf speakers.
BTW; It's been an interesting thread; I've learnt a lot.
I had a look inside too and the buid quality and X-Over parts quality are all very good for the price. I bet you'd find loads on uk ebay if you were after a cheap set of decent book-shelf speakers.
BTW; It's been an interesting thread; I've learnt a lot.
I've managed to improve commercial budget loudspeakers a lot with a few tweaks. It's quite enjoyable to hard solder proper loudspeaker cabling inside a cabinet, because commercial products usually use thin cables and loose clip on connectors.
They also tend to use cheap non-polar electrolytics around 2.2 or 3.3 microFarad on tweeter crossovers. You get a lot less sibilance on female vocal using Maplin's Polypropylene Capacitors which are as good as it gets IMO:
Audio-Grade Polypropylene Axial Capacitors : Polypropylene : Maplin Electronics
I think any audiophile worth his salt buys a gas soldering iron, solder and some wire cutters and gets loose. 🙂
They also tend to use cheap non-polar electrolytics around 2.2 or 3.3 microFarad on tweeter crossovers. You get a lot less sibilance on female vocal using Maplin's Polypropylene Capacitors which are as good as it gets IMO:
Audio-Grade Polypropylene Axial Capacitors : Polypropylene : Maplin Electronics
I think any audiophile worth his salt buys a gas soldering iron, solder and some wire cutters and gets loose. 🙂
I believe Eltax are using 4 to 8 ohms to precisely describe what they are selling.
4ohms speaker over part of the frequency range and 8ohm speaker over the other part of the frequency range.
This Eltax is definitely not a 4ohms speaker nor can it be called a 6 ohms speaker.
It is a speaker using two different impedances and is correctly labeled 4 to 8 ohms.
I think you guys are overlooking the obvious and making things much too complicated:
I do agree with You Keriwena :
Usually it's written 4 ohm or 8 ohm on speakers but not 4-8 ohm.
Since impedance rules are :
- with the bridge on = (R1xR2)/(R1+R2) = 8x8/8+8 = 4 ohm
- Without the brigde = R1 = 8 ohm et R2 = 8 ohm
So it would explain with the manufacturer wrote 4-8 ohm on the label.
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