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bennybee

Advent Heritage Xover upgrade produces too much treble

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Hi List,
I am very glad to have found this forum. Iam an Advent fan since I heard the Large Advent and the Powered Advents about 20-25 years ago. They were beyond my budget then, so my first pair of Advents were the 5004 (I think that's what they were), but about 15 years ago I bought the Heritage pair that I'm still enjoying today. Reading a thread here by 'jmitchnh' a few weeks ago, I decided to upgrade the crossover filters like he did. The original capacitors were the KSC electrolytics of resp. 20MFD and 6MFD (+/-10 p.c.) 100V. I replaced these by black Jantzen Crosscaps of 22uF and 6.2uF (+/-10p.c.) 400V.
I could not find the exact same values but figured that these were within acceptable limits. The original KSC 1ohm resistor was also replaced by a Jantzen MOX 1ohm 10W resistor.
I installed the components last saturday and was at first very enthusiastic. I 'upgraded' one speaker and compared L/R with the old one : there was a bit more and somewhat tighter bass, a more open and brighter sound, clearer voices (less 'boxy'). Persuaded that there was an improvement I then also tackeled the second speaker. After a couple of hours though, I began to notice that there was way too much treble, to a point that it becomes annoying and even painful to the ears with f. ex. guitar solos (Santana on 'Europa') or high pitched voices (Temptations' ooh-ooh-ooh crying high falsettos). I need to turn down the volume and the treble control of my Sony amp TA-FA50ES. Will this improve after a burn-in time of the caps? I must say that until now I din't believe in the voodoo of burning in cables and capacitors with pink noise or hundreds of hours of music or what-have-you, but given the slight disappointment in my 'upgrade' I'm now silently hoping that burning in caps will have an effect...! Could the small difference in value of the capacitors be the reason that too much energy goes to the Advent's tweeter? Or is this the character of these particular capacitors and should I try another brand of caps? Can I perhaps add a resistor somewhere to reduce the energy sent to the tweeter? Thanks in advance for your advice and for sharing you experiences.
kr, Bennybee

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Here are the complete crossover component values for the Advent Heritage (Classic Heritage, twin woofer). I originally only replaced the caps, but then discovered at higher volumes, the iron core inductors were saturating. I replaced the woofer inductors with Erse iron core inductors and the saturation issue was resolved.

I also replaced the tweeter inductor with an air core type.

I used DATS 2 to make the measurements.

Advent Heritage Crossover Values_062618.pdf

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@THD+N   How did you measure the inductor saturation?

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I think this is a good example of users, out in the field, changing things around in a speaker without considering the original design or why certain components are in a speaker. I realize cost is often a major factor in speaker design and construction but, the thing is, the components in a speaker ARE the components in the speaker and if you go changing them, you may well alter the sound but not necessarily for the better.

Doug

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On 8/24/2018 at 9:10 AM, Pete B said:

@THD+N   How did you measure the inductor saturation?

Pete,

No scientific (or "real") test was performed to determine the inductor saturation, but you could hear it saturating. Bass got flabby and distorted much too early before power handling was an issue.

 

In another life, I previously worked at Recoton and Audiovox (1997 to 2015), who owned the Advent and AR brand names. I worked closely with the engineers who designed and developed the later Advent and AR speakers. I designed and developed car audio. The Advent brand was price sensitive (from a production standpoint) and it showed in some products. Simple crossovers with small inductors that would just allow the woofers to handle the rated power, cheap (no brand name) capacitors, etc.

 

Although the Advent Heritage was made prior to my employment at the company, if the bean counters would have spared an extra dollar or so, the Heritage crossover would have been respectable.

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You are not only person to work for the "Advent/AR brand".

Been there done that, International Jensen employee (General Magnetic Co.) 1989-97. Helped design the bucking magnet shielding style for the shielded Prodigy Tower,  Audio Focus, &  Audio Cinema center channel speakers. Also own over 30-pair of Advents speakers including the ultra rare new vision 250 bookshelf speakers 

Remember Jensen back in the day owned the magnet, cone, voice coil, speaker frame / wood cabinet companies. Also back then, Jensen owned Advent, AR, NHT, and Phase Linear. 

Good to know another employee, BTW it was the best employment time of my life, working for Jensen................

 

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3 hours ago, NewVision250 said:

You are not only person to work for the "Advent/AR brand".

Been there done that, International Jensen employee (General Magnetic Co.) 1989-97. Helped design the bucking magnet shielding style for the shielded Prodigy Tower,  Audio Focus, &  Audio Cinema center channel speakers. Also own over 30-pair of Advents speakers including the ultra rare new vision 250 bookshelf speakers 

Remember Jensen back in the day owned the magnet, cone, voice coil, speaker frame / wood cabinet companies. Also back then, Jensen owned Advent, AR, NHT, and Phase Linear. 

Good to know another employee, BTW it was the best employment time of my life, working for Jensen................

 

I recently picked up some Prodigy Towers - anything notable about the woofers that the class would like to hear?

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Since I have two pairs of Prodigy for my HT, main/front center and that they are 27 years old now, I too will mod and restore the prodigy.

But first, I must learn to mod the crossover using SoundEasy v23 Loudspeaker Design Software. The woofer is a 1st order and the tweeter is a simple 2nd order.

The real question is, Can I make the crossover better using 3rd order ?

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Other than the same 8" Prodigy woofer is used in the Graduate and Heritage lines. The shielding 8" woofer is just made with a reversed magnet glued to the woofer magnet to cancel the gauss field. 

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