• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

BEHRINGER KM750 & KM1700 official specifications vs actual specifications

OP
djtetei

djtetei

Active Member
Joined
Jul 5, 2022
Messages
137
Likes
62
Location
România
So, my dear friends, as I promised, I am now able to post Behringer answer to my latest support ticket enquiring about standards and practices they use to rate their power amplifiers.

My questions were as follows:
Currently Behringer power amplifiers power ratings are expressed using the term "max power" and Behringer officially states that "you can expect the RMS/continous power rating would be "around" half the declared max power rating".
What does "around" half really means? It is "around half" at least or "around half" at most?
Specifying "Max power" only for a power amplifier could mean that its continous long term power rating may be anywhere over "around half" or under "around half", which makes it difficult to design and calculate a sound system and to choose the proper power amplifier for the loudspeakers for which the continuous and peak power ratings are known.
What methods or guidelines does Behringer use or follow to determine the power rating of its power amplifiers?
Are amplifiers tested with sine wave test tones at different frequencies inside the supported bandwidth?
Are amplifiers tested with pink noise (what crest factor) inside the supported bandwidth?
Are amplifiers tested with both or all channels driven?
What is the maximum THD allowed during the power rating procedure?
What is the resolution of the digital signal processing units used on the power amplifiers with DSP?
Why not publish both "max power" and "continuous" power ratings to make it easier for a customer to asess the true capabilities of an amplifier?
Suppose I would like to buy a Behringer KM 1700 and I would like to know the following parameters:
- continous power rating at 8 ohms, both channels driven, with less than 1% THD
- continous power rating at 6 ohms, both channels driven, with less than 1% THD
- continous power rating at 4 ohms, both channels driven, with less than 1% THD
- how many dB between two markings on the front panel gain controls
Thank you kindly!

Behringer answer is as follows:
This is in relation to  CAS-616983-H2V9Y7
"We no longer list our amp power ratings by RMS as these tend to not give true results as tests are always done using signal generators and specific waveforms which don't reflect in comparison to music. Program music comes at fuller frequencies and non linear dynamics which is nothing like a test tone generated from a signal generator. There are lots of topics on the internet about this should you wish to look into it more.
As a rule of thumb, you can assume RMS is around half the peak value
With regards to the specifications, I am afraid that all I can give you is what is printed in the Quick Start Guide which I have attached to this e-mail.

I am sorry that I cannot provide the information that you were looking for."


At your service,
Nigel Turner
Music Tribe

Basically, Behringer sticks to their own bulshit, as it is published in their official knowledge base article: "What is RMS".
 

LTig

Major Contributor
Forum Donor
Joined
Feb 27, 2019
Messages
4,590
Likes
7,405
Location
Europe
So it's like BOSE - Buy Other Sound Equipment ... ;)
 
OP
djtetei

djtetei

Active Member
Joined
Jul 5, 2022
Messages
137
Likes
62
Location
România
If you value honesty, reliability and a proper customer support, yes, one has to look at sound equipment manufacturers who really stand behind their products and truely care about the brand image.
If, on the other hand, one looks for cheap "bargains" only, he may buy Behringer with all their cheap bullshit, dishonesty and cheap (inexistent) customer support.
 
Last edited:

Wolf11Man

Member
Joined
Jan 19, 2022
Messages
6
Likes
0
I do not share your conclusion, as many Behringer products are well build and most reasonable priced. Many people would not be able to afford PA stuff if Behringer was not there to put pressure on the market. Also, their service is one of the best I have ever experienced. They fix your amp under warranty "no question asked".
Amps are only a fraction of Behringers products. Look at all the brands from "Music Tribe".

I also dislike the way they give power ratings of their amps. This has not allways been that way, a few years ago Behringer gave precise RMS numbers of their amps in 4 and 8 Ohms. It surprised me when they suddenly changed the online user manuals of otherwise unchanged products.
Attached a page of an old, "honest" manual of the 1th generation iNuke. Clear rms numbers, which are not very impressive... independent tests have confirmed them.

If you choose equipment with some cleverness or ask for advice from a reputable dealer like Thomann, you will do fine with Behringer products, including amps.
Please do not make single negative experiences a general rule.
 

Attachments

  • iNuke_real_spec.pdf
    141.7 KB · Views: 43
Last edited:
OP
djtetei

djtetei

Active Member
Joined
Jul 5, 2022
Messages
137
Likes
62
Location
România
I am not debating the build quality of their products, because, over the years, I used some of their equipments intended for studio users and, lately, the quality of the assembly was raised and the rate of failure has decreased.
My problem is with the fact that, even when asked to provide more detailed information about their products, like power amplifiers, they shy away and evade to provide the information, although they should have it available.
In order to provide a power rating for an amplifier they have to measure its performance and one cannot perform measurements without using test tones, like sine waves and pink noise, because these test tones are specifically made to give a measurement, like RMS voltage, RMS current and frequency response. So, they have to know all those measurements in order to provide a rating for their amplifiers.
They keep telling that they stopped providing power ratings by the RMS because the results are not consistent with the music program structure. While this is true to a point, knowing the continuous power rating measured with a sine wave test tone can help you "derate" and estimate the real life power delivered with higher crest factor audio material.
Behringer evade to provide the continous sine wave power rating because they use weak power supplies with just enough capabilities to reach a certain RMS voltage and are current limited, lacking the power reserves required to provide up to 4 times the power on peaks.
You say that their customer service is top notch. Maybe you had good experiences with their customer support and parts availability. Personally, I wouldn't dare to venture in dealing with their customer support and parts availability, because even their local dealer in my country don't trust their service.
Try asking Behringer for a block diagram schematic and they will reject your request on the ground of safety hazard or know-how protection.
Try asking Behringer to provide you the technical specifications for a toroidal transformer used inside one of their amplifiers and they will not respond.
So, you see, while their products are appealing because of a price/performance ratio, the long term customer satisfaction and service options are not fully satisfied. Many users prefer to simply buy another Behringer product than to try repairing it. While I intended to try their amplifiers, just to see how they perform, personally, I am not comfortable with their policies of refusing to disclose useful and pertinent information about an amplifier specifications.
Throwing a number out here, like "max power", without providing any details about how that number was measured tells you nothing about the real, stable, performance. Statements like "RMS power is assumed to be about half the max power rating" is also not reassuring, because "about" cam be anyware. A true and sincere statement would have been "the RMS power rating is guaranteed to be at least half the max power rating".
In my profession I don't want to "assume" a power rating, I want to know it and to trust it, withing 1 dB tolerance.
I truly want to give Behringer the benefit of the doubt, because I know they are trying to improve their products quality, but their secretive attitude is what stops me to do it.
Take all their power amplifiers lineup with "ATR - accelerated transient response" technology and non of their user manuals have any mention about the slew rate parameters.
You also mentioned Thomann in your post. I constantly work with Thomann and they are more open about disclosing technical specifications and providing any assistance. Also, Thomann do not shy away from specifying the RMS power rating of their amplifiers.
In comparison, I never had any problems with Crown amplifiers over the years.
 
Last edited:

Wolf11Man

Member
Joined
Jan 19, 2022
Messages
6
Likes
0
I'm really no Behringer fan boy, but accept this brand for low cost, entry level gear that does a good basic job when used with intelligence. Last is crucial...

Concerning the after sales service, I only care about repairs under warranty. These depend strongly on the sales point. Many dealers wait for month until they have a reasonable amount of warranty returns. This time is then always blamed on "the factory". They may even hope to sell new stuff, if gear is really needed and repairs are delayed. Don´t blame that on Behringer, I had 2 repairs and one needed 2 weeks, the other 4. That is 100% acceptable.

As a German, I'm used to manufacturers not giving out any service data at all. 30 years ago any stupid schematic was called "Top Secret". Since the internet has opened channels to other country's, where there are laws for providing service data to independend parties, this has improved. Some companys, like Fisher HIFI Japan, included schematics in any product they sold. Was a rare exception and very surprising for me, by the way.

Anything about rating and even more, producing amplifier power, is a theme to fill a book. I build amplifieres that had 250W rms at 1% THD and "music", "peak" or "Program" power only a few Watt apart, as the transformers where overdimensioned and did not care for the load. Other really started to pump when driven hard, when lots of filter capacitors and too small transformers meet. Clipping can be hard or soft, depending on amp design.
SMPS are a very different breed, you can design them in any direction, just like D-amps, where often software has control over the hard wired part. So you can't even tell how the amp behaves.
"ATR" seems to be simply a marketing invention, I found nothing special in the schematic. Anyway, the KM750 amp sounds OK and would have been called "High End" 30 years ago, except for the loud fan. Today there is hardly any price difference in parts between a good and bad A/B design. 30 years ago not every developer knew how to dimensin the parts for a perfect result.

Just a last point: The KM1700 (class H) and KM750 (clas A/B) share the same type and number of power stage transistors. So driven to the limit the KM750 may be the better amp and more reliable than the KM1700. Behringer sure looks for lowest production costs.
 
OP
djtetei

djtetei

Active Member
Joined
Jul 5, 2022
Messages
137
Likes
62
Location
România
driven to the limit the KM750 may be the better amp and more reliable than the KM1700
Personally, I never drive the power amplifiers or the loudspeakers to their operational limits, because I allow for 3dB to 6 dB of headroom between the loudspeakers power capacity and amplifier continous power rating. I monitor the entire signal chain with metering, set the gain stage for the optimum signal to noise ratio and never allow the mixer master outputs to go over 0 dB mark. As an example, if I need 300 W to fill a space with sound to a certain SPL level, I use speakers with at least double continous power capacity (more for live sound performance) and an amplifier able to deliver 3 - 6 dB more continous power than the loudspeakers continuous power capacity. The goal is to ensure clean sound for the audience and protect the electronics from heat.
I am curious: can an amplifier design, like Behringer KM 750 or KM 1700, be modified (higher quality capacitors and transistors replacement) to improve its performance and reliability?
 
Last edited:
OP
djtetei

djtetei

Active Member
Joined
Jul 5, 2022
Messages
137
Likes
62
Location
România
Talking about quality components?
A side by side comparison for fan noise between a Crown XLI 1500 and Behringer KM 750 will reveal the fact that, on quiet passages, the fan noise of the latter is clearly audible at all speeds even from 4 meters away, while on Crown XLI 1500 you literally have to put your ear agains the case to hear some fan noise, which I would call it "a soft whisper".
On power output delivery a Crown XLI 1500 will effectively wipe the floor with a Behringer KM 1700.
Yes, one can make a modification on the KM series to fit some quieter fans, but this requires time and money spent, instead of enjoying the damb thing capabilities right from the start.
Sonically, both Behringer KM 750 and KM 1700 are clear and can be used without problems, but the Crown XLI power reserves clearly tilts the balance a lot in its favour.
Personally, I would have liked to see those Behringer KM series amplifiers perform better, but, for the time being Behringer is not "there" yet.
 
Last edited:

Wolf11Man

Member
Joined
Jan 19, 2022
Messages
6
Likes
0
I don't understand what you are writing about, the Crown is twice as expensive as the Behringer. Most people will understand that the much more expensive Crown is better, stonger or more silent than the Behringer.
Anyway, since Behringer has increased its retail prices, the difference may have become a little more favorable for other amps. My KM750 was 139 € including tax and shipping. Today it is 209€.
 
OP
djtetei

djtetei

Active Member
Joined
Jul 5, 2022
Messages
137
Likes
62
Location
România
In Romania, one (including myself) can buy both Behringer and Crown from Senia Music, which is the official dealer and service partner for both brands, for the following amounts:
- Behringer KM 750 - 209 EUR
- Behringer KM 1700 - 256 EUR
- Crown XLI 1500 - 359 EUR
I tested all three amplifiers and my conclusions were as follows:
- Behringer KM 750 and KM 1700 have a sturdy assembly, with built-in support feats and deliver a good and somewhat brighter sound, without any background noise, but with perceptible fan noise during the quiet passages, even when idle. The TRS inputs and the 26 dB (fixed gain) input sensitivity setting adds to their value.
- Crown XLI 1500, compared to the KM 1700, has a higher quality assembly and finishing, delivers more power, with a neutral sound and its fans are a lot quieter then those fitted inside Behringer KM 750 and KM 1700. Readly usable in home audio environment.
Personally, I opted for the Crown XLI 1500 because I wanted simple and reliable class AB architecture, to ensure at least 3 dB of headroom (real reserve power) between the speakers continuous power rating (165 W / 6 ohms) and the amplifier continous power rating and because of the neutral sound.
The Behringer KM series are, indeed, value for money, but, in my opinion, their value could be increased if Behringer would decide to upgrade them with higher quality fans, in particular, and to publish real figures for the continous and peak power capabilities. There is nothing to lose in being honest and offer your customers the option to make an educated choise.
 
Last edited:

juliopr

New Member
Joined
Jul 9, 2020
Messages
2
Likes
1
Hi everyone. I have 2 of these(KM750)units to power a pair of custom made line arrays consisting of 12 6" midbass and 9 B&G NEO8 PDR drivers per channel, subs powered by another power amp and They have worked perfectly for the price. System is a miniPC using JRiver via USB to a Denafrips Ares 2, balanced outs to a Chi-Fi clone of a MBL 6010 preamp, balanced output to an Ashly 3 way analog crossover and then to the power amps. Maybe since I am multiamping those power issues do not affect me as others...
 

TonyJZX

Active Member
Joined
Aug 20, 2021
Messages
249
Likes
184
check this out:


they probably come from the same factory

check the power figures

i have a story about the KM750... I put a deposit on this one and it was never able to be delivered... so the music store I bought it from gave me a call back and said that the unit is still not in stock but the price is gone up so you have to pay more... to wait...

So nah... I mean.. I cant be bothered with this kind of supply chain issues. I ended up buying a proper power amp for many multiples of the km750.

I think people have to be realistic about what is deliverable for your $200-$250 usd... I dont expect a 19" rack sized unit to be able to provide the given power figures given that kind of money... its just not a reasonable expectation.

I dont expect the best in sound quality... this is a PA amp...

this is kind of speaker you're supposed to match it up to:


the intention is that you use a basic mixer, mic preamp and karaoke mics so you can run music and PA for your local church group or seniors bingo.... i'm pretty sure i seen this exact setup at your local kids fairs with your hotdogs and burgers etc.

the value proposition is that you're getting a real 100w x 2 @ 8 ohms with reasonable thd and good reliability and as long as it works under warranty then you're good to go... once it goes BANG out of warranty you chuck it

I mean look at all the connects: rca trs and xlr.... its an embarrasment of riches. Speakon and bananas too!

I think also if you're on this forum you probably arent the target user for this amp.

You can probably buy a lot better from any number of China Class D for less money... SMSL, Topping etc. OR... step up to a proper A/B unit from Emotiva or whatever...
 

Head_Unit

Addicted to Fun and Learning
Forum Donor
Joined
Aug 27, 2018
Messages
967
Likes
476
I also dislike the way they give power ratings of their amps. This has not allways been that way, a few years ago Behringer gave precise RMS numbers of their amps in 4 and 8 Ohms. It surprised me when they suddenly changed the online user manuals of otherwise unchanged products.
That is because people like @amirm started measuring this stuff and showing up their lies. It's like back when the Camaro came out with 305 hp, and the Mustang Cobra which was supposed to be 280 hp suddenly came out with...305!! Until independent dyno tests showing this was a lie, upon which Ford tried to blame their exhaust supplier and did a bunch of rework. Behringer instead is backing up to blah blah blah that RMS is not important. Well, kind of true, even compressed music has some dynamic range.
- Then again it's not hard to find users that slam the volume to "11" or even 12 or 13...amps should be able to survive that.
- It's also rather bull-oney to say all that because it ignores the fact that speakers are NOT resistors, so maybe you need that constant power not really for constant power but so that peaks don't clip into nonresistive low impedances common in speakers.
- It also makes it really hard to compare dollars per watt, and is just shyster marketing, long explanations or not. If Behringer wants to go down that road they should emulate NAD/Proton of yore and give RMS and peak ratings defined with a distortion level and a time rating (100 mS or 1 minute or whatever).
 
Top Bottom