HIFI Speaker active crossovers ...


Since the speaker and crossover are where most of the distortions and loss come from in the audio path, why has hifi not gone to active crossovers to eliminate these effects. Most active studio monitors and touring PA have... 

sozocaps

Then we will quickly find ourselves in the "High End" Active crossover offering game very quickly LOL

We still await the perfect @kenjit designed and produced transducer.  As much as I dearly loved the blokes from Top Gear, their brilliant entertaining critiques, no serious auto designs were ever put forth.  They were not foolish enough to endeavor in practical design proposals encompassing a whole product concept. No proof of concept attempted.

They were smarter than that.

@mike_in_nc Wrote:

An active xover divides the signal at line level.

You are correct. For a bit of history, see below JBL catalogs from 1964 and 1967, they offered powered and non powered speakers with passive crossovers. See 1964 catalog page #43 JBL solid state stereo energizer. The JBL Hartsfield was the first powered speaker in 1962. In 1972 JBL made the 4350A active only. 😎

Mike

https://www.lansingheritage.org/html/jbl/catalogs/1964.htm

https://www.lansingheritage.org/html/jbl/catalogs/1967.htm

 

I agree, JBL is doing it the right way, rather than putting the xover and amps inside the speaker cabinets. Not the case with such active speakers as those made by Genelec, KEF, and so on.

@mike_in_nc Wrote:

@ditusa -- According to the owner’s manual, those JBLs have no crossover at all and should be used with a specific external crossover and specific amplifiers.

The crossovers are in the Crown amp design for the M-2 speakers. One Crown® iTech 5000HD power amp for each speaker, or One Crown® iTech 3x3500HD power amp for two (2) speakers. From the M-2 manual:

Specifications

System Format 2-Way Floor Standing or Soffit Mountable
HF Driver D2430K Dual Diaphragm Dual Voice Coil Compression Driver
LF Driver 2216Nd 15 in (381 mm) Differential Drive® Woofer
Crossover Frequency 800 Hz
Frequency Response (±3 dB) 20 Hz - 40 kHz
Coverage Angle 120° H x 100° V
Sensitivity 92 dB
Continuous/Peak SPL@ 1m 117 dB /123 dB; 108 dB Peak SPL @ 8m
The System Requires One Crown® iTech 5000HD power amp for each speaker, or One Crown® iTech 3x3500HD power amp for two (2) speakers.
Amplifier Power Rating 1,200 Watts into 8 ohms
Input Connectors Spring Terminals
Enclosure 25 mm (1 in) MDF
Finish Satin Black Lacquer
Included Removable ABS Grille with Black UL Compliant Fabric
Dimensions (w x h x d) 508mm x 1256mm x 355.6mm (20in x 49.5in x 14in)
Net Weight (each) 58.5 kg (129 lb)
Maximum Peak SPL 123 dB
Maximum Continuous SPL 117 dB

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What model is yours?

JBL model 4435 with JBL 5235 active crossover and JBL #52-5130 crossover cards design for 4430,4435 studio monitors. 😎

Mike

 

@ditusa -- According to the owner’s manual, those JBLs have no crossover at all and should be used with a specific external crossover and specific amplifiers.

An active xover divides the signal at line level. For it to work properly, the amplifiers need to be known quantities. I have never seen a speaker that contains the xover but not the amps, though theoretically they could exist. An active bi-amped speaker typically has two amps in it. What model is yours?

 

By far the most distortion in a speaker is caused by cabinet resonance and driver breakup, not because of passive crossover components.  

 

@mike_in_nc Wrote:

For an active crossover to make the most sense, the speaker needs power amps built in.

I don’t think so. The speakers below have an active crossover with no power amps built in and are excellent speakers. Also, my home audio speakers are actively bi-amped with no built in power amps and sound great. A speaker, with built in power amp(s), is called a powered speaker, active or passive is in reference to a speakers crossover topology. In my opinion, amps inside speakers is not a good idea because the amps are subject to all the vibrations and air pressure inside the speaker cabinet.😎

Mike

 

Unfortunately there are some sinister reasons that active technology is not being used within the speaker industry. There are many conspiracies witthin the speaker industry and this is just one. There has been a collusion by the amplifier manufacturers and the speakers companies to ensure that the hifi marketplace is not monopolized by the speaker industry, if active technology was the only game in town. It was subsequently agreed that the amplifier companies would continue to market their mega expensive $50K amplifiers to the marketplace while the speaker companies continued to produce speakers using inferior passive technology. This would ensure that both sides would profit. 

Moreover the speaker companies had another secret motive. They did not want the public to interfere with the way their crossovers had been tuned. Crossover tuning is and has been a black art for a long time. No speaker company will disclose their transfer functions the same way food companies will not reveal their secret ingredients. The crossover plays a big role in defining the sound quality that a speaker produces and without it, there would be no way for the public to difefrentitate between different speakers. If, God forbid, the power to adjust the crossover got into the hands of the audiophile community, it would be game over for the speaker companies if audiophiles found that most speakers sounded about the same when their crossovers had been tuned similarly. 

Active technology would also negate the need for exotic expensive amplfiers since once you remove the passive technology, all speakers would be easy to drive. 

The hifi market is driven by profit rather than sound quality. That is the short answer. 

For an active crossover to make the most sense, the speaker needs power amps built in. Historically, audiophiles have not wanted that. Maybe views are changing with a new generation.


What I will use in biamp setup, has dual sub outs, crossed for Sub at 60hz/24 db for dual tekton 2-10 and 500/12db mid highs for a pair of bi-amp wired tekton double impact se upgrade with the actual tweeter BE upgrade.  
 

SS amp for mid bass and will get be getting an 85w/c tube amp for mid highs.

Unfortunately, I am still gathering all the pieces.. waiting on the subs and the tube amp.  But just the SS to DI/SE from a Gustard r26 using bt 96khz PCM input (qobuz) sounds really good. (Just dac pre-amp out.. waiting for my rebuilt vintage pre-amp I had heard 20 years ago and always wanted)

Still having issues with tidal dropping out often.. so far I have never had qobuz stream interruption . (24/96 mainly from qobuz) though my purchased 24/192 and dsd do sound better, especially at higher volumes.. to me anyway, higher volumes really showcase the amount of data getting put under the curve.

Had my old klipsch bi-amped with some older amps with this active crossover and just one sub and it sounded alot better than without xover and bi-amped..  the new setup should (had better) sound even better when I have everything.. else I’ll be selling some stuff..

 

Like everything else, there are outstanding and poor examples of each type, and there are pros and cons to each. Many crossovers have to address multiple issues as well as the basic function of blocking low or high frequencies. The execution of the crossover and addressing all of it’s task is more important than the type. Many, many speakers have really dreadful crossovers and lousy parts. Even many that are well engineered still use low grade parts, so ultimately many of us have only been exposed to very poor examples of passive crossovers.

Recommended viewing:

 

Hi, please read the 2  dozen discussions in this very forum on this topic. :) Thanks!

To save money! An active circuit is way more complex and costly than stringing together a bunch of caps, chokes and resistors. It requires a power supply - a part of the total cost.