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In the Forum: Horn-Loaded Speakers
In the Thread: Anything wrong with wide bandwidth horns?
Post Subject: Horns do what they doPosted by rowuk on: 10/2/2012

let's ignore any issues of sound quality first. A horn loads its drivers and increases efficiency only at certain frequencies. The frequencies that are more efficient are based on length, taper and size of the mouth. That means that it doesn't matter if a 12", 6" or compression driver feeds the horn, the band with increased output does not really go up or down. This means if a Synergy horn has the rough dimensions of a 300Hz conical horn, we get appreciable gain from 450 to 2400Hz and pattern control from 600 to wherever the HF driver runs out. To get flat frequency response, we have to heavily equalize the band where we have gain DOWNWARD to match bass and treble reponse that do not have this gain.

Let's introduce sound quality. Proper horns are the opposite of transmission lines. Their length is so short that standing wave resonances are not a factor for the desired pass band. If I run a big horn well above the "decade", standing waves at frequencies that are a multiple of the length of the horn in fact color the sound. The horn becomes a transmission line. Below the passband, the attached drivers become direct radiators with a funnel in front of them - typically horn "honk" is the result.

I have heard the Synergy horn in a nice home setting and think that this is basically not a match for a proper horn system. It still sounds very good. The improvements over conventional speakers are in clarity in the midrange - where the horn has gain. I did not consider the HF to be close to other fine solutions. Other wide band horn solutions are the "econowave"/PI and many other 2-way systems where the horn gain is equalized down in the pass band to a dynamic woofer. This approach sounds to me very similar to the synergy horn. I have experimented with this concept and ended up taking the EQ off allowing the horn to roll off naturally at HF and then adding a tweeter. Taking the EQ off of the horn improved the SQ dramatically.

As Romy has often stated, horns have a personality of their own. If you treat them as the decade devices that they physically are, you get the best results. Extension comes only through comprimise. Danley provides intelligibility, pattern control and efficiency - the premium factors for PA. He does this without "castrating" the sound. At lower levels, the playback can be far superior to conventional drivers due to the much lower distortion where the horn has gain. I find violin, piano and other upper octave melody instruments to not sound natural on any equalized horn. With jazz and rock recordings all bets are off as the "immediacy" of this type of speaker becomes an artistic "coloration" that is not bad.....

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