I don't have a specific recommendation.

Any good modern solid state amplifier will not have issues with transient response, damping factor, or frequency response.  (Transient response is related to frequency response so as long as the amp is flat to 20khz or so, it's nothing to worry about.)

I assume you are just looking for a power amp?      For the most bang-for-the-buck, I shop somewhere that sells pro audio equipment, such as Musician's Friend.   

Since I assume this for "studio use", be aware that many high-power amplifiers have cooling fans and the acoustic noise could be an issue. 

200W is probably overkill for that little 6-inch woofer.

Quote from: DVDdoug on 2015-03-30 19:21:34

I don't have a specific recommendation.

200W is probably overkill for that little 6-inch woofer.

Hi very inefficient transmission line design. Manufacturer recommended 200w per channel but not to use full power  (headroom). What the difference if any between a power amp and hifi audio wise  ?

something cheap 200w per channel is fine some recommend class d but I don't know.....any suggestions  ?

Around $200usd http://alesis.com/ra500

Quote from: ajinfla on 2015-03-31 13:50:13

Around $200usd http://alesis.com/ra500

Or this suspiciously-similar Behringer A500: http://www.behringer.com/EN/Products/A500.aspx

Which was part of a inexpensive setup that handily matched high-end audiophile gear in a well-known blinded test: http://matrixhifi.com/ENG_contenedor_ppec.htm

Quote from: KozmoNaut on 2015-03-31 14:49:21

Quote from: ajinfla on 2015-03-31 13:50:13

Around $200usd http://alesis.com/ra500

Or this suspiciously-similar Behringer A500: http://www.behringer.com/EN/Products/A500.aspx

Which was part of a inexpensive setup that handily matched high-end audiophile gear in a well-known blinded test: http://matrixhifi.com/ENG_contenedor_ppec.htm

I've bench tested, listening room evaluated and stress tested A500s in live sound situations. It is what it is - a good amplifier with a caveat (below). It has a little design flaw that seems to have little or no audible consequences and does not hurt reliability. It can be completely avoided pretty easily.

An interesting comparison can be formed with the classic QSC USA400 which is also a good 120 wpc power amp. But the QSC is old tech and weighs twice as much if not more. Cost more than twice as much in constant dollars, so maybe 3 times as much in inflated dollars. The cost and avoirdupois does not help the performance or sound.

The A500 part-volume distortion problem is shown here: A500 Youtube Video  It's about 0.5% THD @ 1 KHz which is worse looking numerically as compared to its sonic effects on music, but only with the volume control set to about 70%. At lower and higher gain control settings, THD drops to less than 0.02%. The problem is due to the design of the input buffer amp, not parts quality or some such.

Quote from: augustine on 2015-03-30 19:28:44

Quote from: DVDdoug on 2015-03-30 19:21:34

I don't have a specific recommendation.

200W is probably overkill for that little 6-inch woofer.

Hi very inefficient transmission line design. Manufacturer recommended 200w per channel but not to use full power  (headroom). What the difference if any between a power amp and hifi audio wise  ?

Rated at 90 dB/W which is average efficiency.

I'd rather have a pair of LSR308s and skip the purchase decision about amps.

Quote from: Arnold B. Krueger on 2015-03-31 10:00:06

Quote from: augustine on 2015-03-30 19:28:44

Quote from: DVDdoug on 2015-03-30 19:21:34

I don't have a specific recommendation.

200W is probably overkill for that little 6-inch woofer.

Hi very inefficient transmission line design. Manufacturer recommended 200w per channel but not to use full power  (headroom). What the difference if any between a power amp and hifi audio wise  ?

Rated at 90 dB/W which is average efficiency.

I'd rather have a pair of LSR308s and skip the purchase decision about amps.

Just going by what the pmc guy said....how flat are the jbls out if curiosity - anyone measured them ?

Quote from: Arnold B. Krueger on 2015-03-31 16:23:14

Quote from: KozmoNaut on 2015-03-31 14:49:21

Quote from: ajinfla on 2015-03-31 13:50:13

Around $200usd http://alesis.com/ra500

Or this suspiciously-similar Behringer A500: http://www.behringer.com/EN/Products/A500.aspx

Which was part of a inexpensive setup that handily matched high-end audiophile gear in a well-known blinded test: http://matrixhifi.com/ENG_contenedor_ppec.htm

I've bench tested, listening room evaluated and stress tested A500s in live sound situations. It is what it is - a good amplifier with a caveat (below). It has a little design flaw that seems to have little or no audible consequences and does not hurt reliability. It can be completely avoided pretty easily.

An interesting comparison can be formed with the classic QSC USA400 which is also a good 120 wpc power amp. But the QSC is old tech and weighs twice as much if not more. Cost more than twice as much in constant dollars, so maybe 3 times as much in inflated dollars. The cost and avoirdupois does not help the performance or sound.

The A500 part-volume distortion problem is shown here: A500 Youtube Video  It's about 0.5% THD @ 1 KHz which is worse looking numerically as compared to its sonic effects on music, but only with the volume control set to about 70%. At lower and higher gain control settings, THD drops to less than 0.02%. The problem is due to the design of the input buffer amp, not parts quality or some such.

yes I had been considering the a500 until I saw that but apparently  you can change some calibration setting in the amp scroll down


http://ixbtlabs.com/articles2/proaudio/behringer-a500.html

so it might be a good option eh ? No idea how to change those wee calibration knobs though....

Quote from: augustine on 2015-03-31 22:54:38

Quote from: Arnold B. Krueger on 2015-03-31 16:23:14

Quote from: KozmoNaut on 2015-03-31 14:49:21

Quote from: ajinfla on 2015-03-31 13:50:13

Around $200usd http://alesis.com/ra500

Or this suspiciously-similar Behringer A500: http://www.behringer.com/EN/Products/A500.aspx

Which was part of a inexpensive setup that handily matched high-end audiophile gear in a well-known blinded test: http://matrixhifi.com/ENG_contenedor_ppec.htm

I've bench tested, listening room evaluated and stress tested A500s in live sound situations. It is what it is - a good amplifier with a caveat (below). It has a little design flaw that seems to have little or no audible consequences and does not hurt reliability. It can be completely avoided pretty easily.

An interesting comparison can be formed with the classic QSC USA400 which is also a good 120 wpc power amp. But the QSC is old tech and weighs twice as much if not more. Cost more than twice as much in constant dollars, so maybe 3 times as much in inflated dollars. The cost and avoirdupois does not help the performance or sound.

The A500 part-volume distortion problem is shown here: A500 Youtube Video  It's about 0.5% THD @ 1 KHz which is worse looking numerically as compared to its sonic effects on music, but only with the volume control set to about 70%. At lower and higher gain control settings, THD drops to less than 0.02%. The problem is due to the design of the input buffer amp, not parts quality or some such.

yes I had been considering the a500 until I saw that but apparently  you can change some calibration setting in the amp scroll down


http://ixbtlabs.com/articles2/proaudio/behringer-a500.html

so it might be a good option eh ? No idea how to change those wee calibration knobs though....

The simple solution is to run it with the gain turned all the way, and drive it with a low impedance source like just about any SS preamp or mixer.  The distortion is vastly reduced when the volume is below 12 o'clock. Its worst at about 2:30 pm.

Quote from: augustine on 2015-03-31 23:33:50

Quote from: Arnold B. Krueger on 2015-03-31 10:00:06

Quote from: augustine on 2015-03-30 19:28:44

Quote from: DVDdoug on 2015-03-30 19:21:34

I don't have a specific recommendation.

200W is probably overkill for that little 6-inch woofer.

Hi very inefficient transmission line design. Manufacturer recommended 200w per channel but not to use full power  (headroom). What the difference if any between a power amp and hifi audio wise  ?

Rated at 90 dB/W which is average efficiency.

I'd rather have a pair of LSR308s and skip the purchase decision about amps.

Just going by what the pmc guy said....how flat are the jbls out if curiosity - anyone measured them ?

Take the latest version of Internet Explorer (11.9600.17690) here:

Gedlee Speaker Polar Map Program Link

One you are sure you have the stated prerequisites, press the Run button which will download a SETUP.EXE file.

Run the Setup program which should load and start the Polar Map program.

Press the Select button in Polar Map to bring up the list of systems that have been tested.

The Behringer B2031 is titled "Behringer"

The LSR308 is titled: "JBL_LSR308"

I notice that I can also run Polar Map under 64 bit Chrome running under Windows 8.1

What a fantastic resource ! Thankyou. I have been looking for something like this for a while ...... You seem like someone who values a critical approach so I hope will not take offence but I have to ask - this is you know.... independent of market forces, bribery, the audiophile mafia etc etc right ?

I'm assuming so as it seems to be measuring Behringers gear as flatter than the Geddes stuff - which seems pretty honest of them!

However if I understand anyone can upload to the database ?

Quote from: augustine on 2015-04-01 12:55:24

What a fantastic resource ! Thankyou. I have been looking for something like this for a while ...... You seem like someone who values a critical approach so I hope will not take offence but I have to ask - this is you know.... independent of market forces, bribery, the audiophile mafia etc etc right ?

Lets put it this way. I was present for taking the data for about 1/4 of the speakers listed. I'm familiar with the software used and I've assisted hands-on with the data gathering. If the data was fudged for presentation on the web to any significant degree, I'd know it.

I've known Earl for a couple-three decades and he's a straight-shooter. Yes he has his opinions and hobby horses but he would never intentionally fudge data or give a misleading analysis.

Quote

I'm assuming so as it seems to be measuring Behringers gear as flatter than the Geddes stuff - which seems pretty honest of them!

What you see is what we got. Earl does not favor on-axis frequency response as the be-all and end-all, but puts a heavy weight on the off-axis data. I agree.

Quote

However if I understand anyone can upload to the database ?

People can submit data points, and Earl will run his software on them, and if the data seems credible, he'll post it.

That's great - I will definitely help spread the word the audio world badly needs something like this - especially for studio monitors  - I have a superlux ecm 999 measurement microphone - is that good enough to measure quasi anechoic ally ? its supposed to be pretty flat (calibrated in the circuitry I guess) but obviously not as good as high end expensive measurement microphones.
Off axis measurements make sense unless you are using a set square to position your head everytime you sit down !

Quote from: augustine on 2015-04-01 20:08:28

That's great - I will definitely help spread the word the audio world badly needs something like this - especially for studio monitors  - I have a superlux ecm 999 measurement microphone - is that good enough to measure quasi anechoic ally ? its supposed to be pretty flat (calibrated in the circuitry I guess) but obviously not as good as high end expensive measurement microphones.
Off axis measurements make sense unless you are using a set square to position your head everytime you sit down !

The Superlux ECM 999 looks like yet another Behringer ECM 8000 clone, which is to say that it looks like it could be very adequate.

Geddes does these measurements with a fine piece of readily downloadable PC freeware named Holme Impulse.

He has a speaker stand about 4 feet tall with a protractor built into it, and manually rotates the speaker and takes a set of measurements, repeat. For more details, please contact him care of his web site.

So he rotates the speaker rather than moves the mic ?

You could move the mic instead?

Also if you want to measure the speaker not the room wouldn't it make more sense to use a more directional mic than an omni ?

How about this ?

https://emotiva.com/products/amplifiers/mini-x-100

Also in general I wonder how reliable are the amps in the active monitors (like the LSR 30x suggested)
as compared to ones like mini-x-100 or similar smaller amps...

else otherwise passive speakers can last very long . (actives do help avoid some clutter on the desk)

An early exemplary and very popular active loudspeaker product, the Monsoon computer speakers had a circuit that continuously monitored the DC resistance and therefore the temperature of the loudspeaker voice coils and backed off on the power delivered to them if they were in danger of being damaged. Consumers and the manufacturer were rewarded with improved reliability and reduced warranty costs.

The electronics package of the LSRs is a bit of mystery meat - we don't know much about it, whether what sample rate it runs at or the details of its crossover or what protection schemes are actually implemented, but the potential is great

Yup - like the tweeters of 2 out of three of my 3 Infinity 100% passive PC 351s which had to be replaced within about a year.

Quote from: Hifisound on 2015-04-04 12:21:43

How about this ?

https://emotiva.com/products/amplifiers/mini-x-100

Also in general I wonder how reliable are the amps in the active monitors (like the LSR 30x suggested)
as compared to ones like mini-x-100 or similar smaller amps...

As always you have to look at that end of the system as a system, not disconnected individual components.

Integrating the speakers and the amplifiers with intelligent system controls provides many opportunities to increase the over all reliability of active speakers. In particular the active part of the active monitor can be a key element in a driver protection system.

An early exemplary and very popular active loudspeaker product, the Monsoon computer speakers had a circuit that continuously monitored the DC resistance and therefore the temperature of the loudspeaker voice coils and backed off on the power delivered to them if they were in danger of being damaged.  Consumers and the manufacturer were rewarded with improved reliability and reduced warranty costs.

The electronics package of the LSRs is a bit of mystery meat - we don't know much about it, whether what sample rate it runs at or the details of its crossover or what protection schemes are actually implemented, but the potential is great.

Quote

else otherwise passive speakers can last very long . (actives do help avoid some clutter on the desk)

Yup - like the tweeters of 2 out of three of my 3 Infinity 100% passive PC 351s which had to be replaced within abo

ut a year.