Hi again guys i have noticed that allthough the amps you guys are making seem very high quality there seems to be a lack of errrm power lol
am i totaly wrong here or do you guys just preffer superior sound quality over overall power
ive always had powerfull systems and have never realy heard a hi end system in action i had a wharfdale system for a few years and i thaught that that was as good as it gets < that probably makes you laugh i have no idea of the status of any brand name
there is a point to this thread somewhere but it seems to have escaped me
ok is a low wattage hi spec system ie below 200 better than having a room full of speakers that make your chest hurt :/and can i eventually make a system that has the best of both worlds
am i totaly wrong here or do you guys just preffer superior sound quality over overall power
ive always had powerfull systems and have never realy heard a hi end system in action i had a wharfdale system for a few years and i thaught that that was as good as it gets < that probably makes you laugh i have no idea of the status of any brand name
there is a point to this thread somewhere but it seems to have escaped me
ok is a low wattage hi spec system ie below 200 better than having a room full of speakers that make your chest hurt :/and can i eventually make a system that has the best of both worlds
lock of power? how much power are you looking for? 100watts R.M.S per channel is a lot and if you combine it with high SPL speakers you will blow your brains out for sure 😱 if you do not care about "Quality watts" and shoot just for very high power, in that case you should look for amp like Crown, Behringer, QSC etc that are Dj's amps that are used in discos, concerts, stadiums, churches etc.They will provide a lot of power but they will sacrifice sound quality. Have you ever heard "True R.M.S power" from old Marantz receivers like 22XXB series? Long time ago I had the 2238B receiver that was "just" 38watts R.M.S per channel and it played really loud using speakers over 92db spl.😉. Right now I have a diy integrated amp that it is around 90 watts R.M.S per channel and I almost never go over 12 o'clock. I also had a Bryston B60 that it is 60 watts per channel and I found it enough power for me, but again there are some people that like or need more power because they have inefficient speakers or big rooms to feel with sound etc. some people say it is good to have the "extra" power...sure it is as long as it is "Quality watts" I would agree too. But in my case I do not feel the need for more power than 100 watts R.M.S per channel. and do not mix R.M.S power with PEAK power😱
If you read through the threads that are here in their hundreds you will find a common thread.
Most systems with reasonably sensitive speakers are quite loud enough when they are operating at really quite low power.
Take for example a good valve amplifier. In Class A most of them were less than 10W and most of them were quite capable of getting the neighbors annoyed.
As long as you appreciate the 3dB rule; twice the volume will require ten times the power; you will understand the relationship between volume and sheer power.
A lot of High Street vendors lie about the amount of TRUE RMS power of their products. I've seen a 3W RMS Chip Amp quoted at 220W PMPO - What utter crap.
A well designed 50W RMS amplifier will normally be more than sufficient for most NORMAL listening.
Most systems with reasonably sensitive speakers are quite loud enough when they are operating at really quite low power.
Take for example a good valve amplifier. In Class A most of them were less than 10W and most of them were quite capable of getting the neighbors annoyed.
As long as you appreciate the 3dB rule; twice the volume will require ten times the power; you will understand the relationship between volume and sheer power.
A lot of High Street vendors lie about the amount of TRUE RMS power of their products. I've seen a 3W RMS Chip Amp quoted at 220W PMPO - What utter crap.
A well designed 50W RMS amplifier will normally be more than sufficient for most NORMAL listening.
IMO, it's easy to buy good inexpensive semiconductors that will give you a high quality amp using a simple and straightforward architecture. Think something like a 50W Self-type blameless. As you get up to the higher supply rails needed for 200+ watts, the choices are reduced and you may have to alter the architecture to accommodate lower voltage front end components. More devices are needed, raising the cost and complicating the mechanics. Protection becomes a huge issue. Obviously it's done all the time, but from a DIY standpoint, 50-100 watt very high quality amps are an easy build. Also, transformers are less expensive and easy to get.
Higher efficiency speakers are better at reproducing a lifelike quality than throwing power at 80dB to 85dB speakers.
200W into 85dB/W will not sound as nice as 50W into 91dB/W.
Now if you were to use the same 50W+50W amps into 96dB speakers, then you would hear clarity. And 1000W into 85dB amplifiers/speakers could never match that performance.
200W into 85dB/W will not sound as nice as 50W into 91dB/W.
Now if you were to use the same 50W+50W amps into 96dB speakers, then you would hear clarity. And 1000W into 85dB amplifiers/speakers could never match that performance.
i would realy recommend the OP to read up what is sound pressure level, and what i the relation of a speaker's SPL and the sensitivity and the input power.
Actualy one may find that 10-15 watts is way WAY too loud for home use, depending on what You drive with it. Speakers that are sensitive as a concrete block will do nothing with it.. And to be honest those space heater speaker designs lack every thing that an efficient speaker has.
Actualy one may find that 10-15 watts is way WAY too loud for home use, depending on what You drive with it. Speakers that are sensitive as a concrete block will do nothing with it.. And to be honest those space heater speaker designs lack every thing that an efficient speaker has.
I agree that higher SPL speakers sound better (to me). The lower sensitivity "hifi" speakers sound fine at lower power, but sound stressed when forcing a lot of watts into them.
I show off a tapped horn sub by connecting a small chip amp and 9 volt battery supply to it. The bass it makes puts some of those little cube "subs" to shame and the distortion is low.
I don't do live gigs, plus I like to retain my hearing, so it is low power and efficient speakers for me.
I show off a tapped horn sub by connecting a small chip amp and 9 volt battery supply to it. The bass it makes puts some of those little cube "subs" to shame and the distortion is low.
I don't do live gigs, plus I like to retain my hearing, so it is low power and efficient speakers for me.
Last edited:
There are two things you might want to look at.
Power (good watts or bad watts):
♦ Here we normally crank up the amp to 1% distortion and then measure watts (RMS1%) while the amp still plays with excellent quality.
♦ In retail, they normally crank up the amp to 10% distortion and then measure watts (RMS10%, aka Music Power).
♦ In the new digital amplifiers, sometimes they'll report as if the duty cycle could be 100% but that breaks switchmode (must pulse, not be jammed "on" near nonstop), so less than half of the figure is useful (for example a 300w switchmode supply burns up if used beyond 150w).
♦ In car audio and at Ebay, they crank up the amp until it explodes and then tell you the amount of watts it takes to explode--also called PMPO.
The moral of the story? Watts@%distortion is meaningful, but miscellaneous quality watts is not.
Efficiency (speakers are the output):
1w, 85db speaker efficiency
2w, 88db
4w, 91db
8w, 94db
16w, 97db
32w, 100db
64w, 103db
128w, 106db
256w, 109db
-or-
1w, 95db speaker efficiency
2w, 98db
4w, 101db
8w, 104db
16w, 107db
27w, 109db
The moral of the story is: Rocking down the house with the pretty little LM1875 is great fun. You just need an efficient speaker if you want powerful audio--because speakers are the output.
To add to this, since many listen with two channels and two speakers 6db should be added to the numbers (3db for the second channel of same power and 3db for the second speaker (twice the cone area)).
No, just 3dB.
The speakers in a stereo set up are too far apart to get any of the extra 3dB from doubled cone area.
The speakers in a stereo set up are too far apart to get any of the extra 3dB from doubled cone area.
ya, agree to that.
but none is stopping the clever speaker desgner to .. use 2 identical 8 ohm midbass drivers in paralell / box. That does indeed gives a good result (depening on a few things, needless to say.. but this is a way to get some SPL if needed 🙂 )
but none is stopping the clever speaker desgner to .. use 2 identical 8 ohm midbass drivers in paralell / box. That does indeed gives a good result (depening on a few things, needless to say.. but this is a way to get some SPL if needed 🙂 )
If you parallel the speakers, then to avoid wearing out the amplifier you'd need to build a parallel chip-amp to drive the 4 ohm load.
When you double the speakers and double the amp current, you've doubled the output. SO, +3db.
That is not without both advantages and problems.
P.S.
The Veritas project shows parallel 10" subwoofers matched up to a dome midrange. Although the option is valid for your choice of either higher crossover point or decreased crossover noise (you don't get both simultaneously) and doubled cone area, there are several considerations to examine more closely. Paralleling cheap woofers, cutting the LE figure in half (making cheap woofers look a lot better) is an alternative to buying a better quality efficient woofer that has a better quality voice coil area, and there is no cost savings with parallel woofers since the hidden cost ends up in the amplifier. Basically, the option of parallel woofers is effective, but you'll need a double-strength (transfo current, double-up output devices, double size heatsink and bigger vents) amplifier. SO, if you built the double-current sturdy parallel amplifier for this use, the prospect is excellent, except that it wasn't better than simply buying a better quality efficient 8 ohm woofer.
P.P.S.
Energy consumption might also affect some people's decisions. Neither class AB nor class D runs as efficiently with 4 ohm speakers. A class AB with a 4 ohm speaker can have obnoxious heat output, which is great if you wanted a heater, but otherwise, you might want 8 ohm or 16 ohm speakers for a cooler running amplifier and smaller electricity bill.
Actualy there are several 16 ohm midbass units out there, witch should present no problem as far as paralelling. Or alternatively one can simply limit the volume (come on, just 2 resistors..) on the chipamp to make sure one does not deplete its current ability. So in other words, if someone is a bit clever then it poses no problem.
Allso, cheap woofers.. well yess it will be 2 times as expensive, but i do have to mention there are verry nice units out there for as low as under 20 usd. a 40 usd woofer will not realy have 2x cona area and motoric force to drive it, at least not likely. I see the main problem in 2 way designs that 2 sources are represented by the paralelled midbass units and this may lead to problems in case the xover point is not low enough.
Allso, cheap woofers.. well yess it will be 2 times as expensive, but i do have to mention there are verry nice units out there for as low as under 20 usd. a 40 usd woofer will not realy have 2x cona area and motoric force to drive it, at least not likely. I see the main problem in 2 way designs that 2 sources are represented by the paralelled midbass units and this may lead to problems in case the xover point is not low enough.
With high power amps you get power headroom. Your amp runs approximately class A at low SPL, and the best of it is that it can drive the speaker easily (damping), meaning low distortions.
With low power amps, even if "high end", most of the time the driving capability is not that good.
For dynamics quality, never underestimate transformer current capability in small amps. Because for certain music program, short time transient can be very high power.
With low power amps, you have to have a "high end" system in order it can sound as big as big power amps. But science wouldn't lie. You will experience the power only for near-field listening. You wont be able to impress your neighbors with the bass 😛
Very clever for a speaker designer, but yet something an amp designer wouldn't do as a first choice.
Actually, the parallel woofer cuts the LE figure in half turning two poor woofers into one good woofer, allowing your choice of either a higher crossover point or less crossover noise. You also cut the woofer crossover inductor size, expense and loss in half. So, the prospect is very clever indeed, quite dynamic and effective.
But, there's a lot of doubling going on.
You get double the cone area, double the power, double the load, double the speaker enclosure size, double the transformer amperage, double the heatsink size, double the standby consumption and double the number of output devices (a Parallel amp is mandatory). So, prepare accordingly.
P.S.
Problems with shaking up the voice band can happen with any high power setup whereby madly moving woofers scramble higher pitches and the cure is a midrange so that the voice band can come out of a speaker driver that isn't doing wild excursions.
Last edited:
intresting...
http://www.diyaudio.com/forums/multi-way/173903-series-vs-parallel-again.html
same drive voltage gains +6 dBL sensitivity, 3 for the double cone area + motor, and a nther 3 dBL for the double power consumption.
That is, IF, the voltage driving the system is the same.
So, if one does not go over the half output voltgae for the amplifier, then will still get a +3dBL gan, without:
having a 2 times larger powersupply, and parelelling amps.
I em sorry to hijack the thred, but i had to add this.
Actualy paralelling woofers (be it 16 ohm or 8 ohm ones for an 8 ohm rated amp) is a win-win situation if the creator knows what he is doing.
(allso, for the same SPL, excursion would be lower. this indeed is desired from quality point of view)
I see no drawback, expect from :
double box size, double cheap woofers (notice, the lastone may actualy be.. not a drawback) a -3dBL attenuator for the input (OR, reduce the amplifier gain by design by 3dBL).
Actualy i'd say it would be a wellworth effort.
http://www.diyaudio.com/forums/multi-way/173903-series-vs-parallel-again.html
same drive voltage gains +6 dBL sensitivity, 3 for the double cone area + motor, and a nther 3 dBL for the double power consumption.
That is, IF, the voltage driving the system is the same.
So, if one does not go over the half output voltgae for the amplifier, then will still get a +3dBL gan, without:
having a 2 times larger powersupply, and parelelling amps.
I em sorry to hijack the thred, but i had to add this.
Actualy paralelling woofers (be it 16 ohm or 8 ohm ones for an 8 ohm rated amp) is a win-win situation if the creator knows what he is doing.
(allso, for the same SPL, excursion would be lower. this indeed is desired from quality point of view)
I see no drawback, expect from :
double box size, double cheap woofers (notice, the lastone may actualy be.. not a drawback) a -3dBL attenuator for the input (OR, reduce the amplifier gain by design by 3dBL).
Actualy i'd say it would be a wellworth effort.
The extra +3dB from the doubled cone area is only available over a restricted frequency range.
The upper limit is set by the distance apart the cones are. When the cones are closer than ¼wavelength you get the full +3dB because the air sees both cones moving and cannot get out of the way, i.e. the air loads the cone and so produces output.
By the time the separation distance has increased to ½wavelength the extra output has fallen to near enough +0dB. Each cone is loaded by the air as if the air sees just the one cone.
Let's suppose your two 12" drivers have a gap between the frames of 1". The cone centre to centre distance is 13". The frequency for which that 13" ¼wavelength is ~250Hz. I believe that the centre to centre part of the definition is up for some debate or experimental proof. Maybe the cone edge to cone edge is the defining distance. That would be ~22", reducing the +3dB frequencies to <=150Hz. As I say, up for debate.
By the time the frequency is up to 500Hz, the extra due to doubled cone area is down to just about zero.
However thta is not the end of the story.
Two separated sources now interfere with each other. Remember the school experiment with waves of water or waves of light?
Two sources produce interference nulls and pluses. You don't want those interference patterns in your listening area. Similarly you don't want a series of nulls or pluses reflecting off a nearby boundary and arriving at the listening position.
Room loading is a different issue.
The upper limit is set by the distance apart the cones are. When the cones are closer than ¼wavelength you get the full +3dB because the air sees both cones moving and cannot get out of the way, i.e. the air loads the cone and so produces output.
By the time the separation distance has increased to ½wavelength the extra output has fallen to near enough +0dB. Each cone is loaded by the air as if the air sees just the one cone.
Let's suppose your two 12" drivers have a gap between the frames of 1". The cone centre to centre distance is 13". The frequency for which that 13" ¼wavelength is ~250Hz. I believe that the centre to centre part of the definition is up for some debate or experimental proof. Maybe the cone edge to cone edge is the defining distance. That would be ~22", reducing the +3dB frequencies to <=150Hz. As I say, up for debate.
By the time the frequency is up to 500Hz, the extra due to doubled cone area is down to just about zero.
However thta is not the end of the story.
Two separated sources now interfere with each other. Remember the school experiment with waves of water or waves of light?
Two sources produce interference nulls and pluses. You don't want those interference patterns in your listening area. Similarly you don't want a series of nulls or pluses reflecting off a nearby boundary and arriving at the listening position.
Room loading is a different issue.
Last edited:
good point with the interference pattern.
a nother good point with the cone gap dstance and the limited freqvency where the 3dBL gain is obtainable.
But do consider that deep tones are the powerhungry/excursion hungry ones.
150 hz would be verry well acceptible, i think.
But i think 12" is a bit big for a 2 way design by default.
Prehaps a 6.5" er would be a more fair example ?
a nother good point with the cone gap dstance and the limited freqvency where the 3dBL gain is obtainable.
But do consider that deep tones are the powerhungry/excursion hungry ones.
150 hz would be verry well acceptible, i think.
But i think 12" is a bit big for a 2 way design by default.
Prehaps a 6.5" er would be a more fair example ?
- Status
- Not open for further replies.