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Refining the Philips HiQ high end

Audiolab 6000A Amplifier

greenhorn

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I got a pair of modded sony bookshelves running philips Hiq drivers in an open baffle setup.

The vocals are amazing, but the two extremes could use some help. I have a sub to help with the low end, but not sure what to do about the high end - It's very coarse and lacks that airiness.

I tried adding a peerless TL25SN (which has a sensitivity of 92dB, and should be able to keep up), bit no luck - the highs seem rough and coarse as ever. I tried reducing the crossover frequency, still no luck

Clicks and pops on vinyl sound like sand grains being dropped onto the speaker cone rather than clicks.

I was thinking perhaps I should add a more sensitive pro audio compression driver - anything else I can do ?
 
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efernand1

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Have you tried a different brand for the highs? Consider using different types....maybe our DiY section may have some past posts to help
 

greenhorn

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i think the problem is that the philips are too loud - I need a very sensitive tweeter OR i will need to LPF the philips driver - which I'm not very confident of doing, and kills the point of using it as a full ranger - most of the posts here are on using it as a full ranger
 

linuxguru

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People generally haven't complained about the old 8" Philips HiQ FRs (now Boston Acoustics), so I wouldn't modify anything except adding a small helper tweeter (which you've done). For helper tweeters used with FRs, a simple 1st-order capacitive XO is usually the best.

If you're willing to experiment with non-reversible mods, you can try doping the cone (or maybe just the whizzer cone) with Polyvinyl Alcohol (PVA) to stiffen it. It may or may not help with air - YMMV. Just remember that once you've doped the cone, there's no way to reverse it.
 

greenhorn

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Where would you suggest i put the crossover point at ?
I didnt want to disturb the vocal range, so crossed over a little high at 4.5Khz. (2x10uF in series with a 1.5uF film cap in parallel)

Should I try lower (3K?)
 

vktarun

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Hi,

The problem you are facing is generally perceived as "shout" by listeners. If you really love the sound and dynamics of Full range driver and wish to live with them then you need to sacrifice on some other area like one easy and effective way to handle this could be use of Equalizers and tweak the 1K to 3K regeion.
There are other ways but then it will become an andless project of getting right frequencies from a fullrange driver, which is not advisable.

Regards,

Vipin.
 

greenhorn

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I guess i had really high expectations - the best Mids I've heard so far have been from FM Rajiv's altec + horns setup, and a Celestion Ditton 25 i heard from the guy i bought my NAD 3020 from. I suppose expecting something like that out of the hiq might have been a bit too much.
 

linuxguru

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Where would you suggest i put the crossover point at ?
I didnt want to disturb the vocal range, so crossed over a little high at 4.5Khz. (2x10uF in series with a 1.5uF film cap in parallel)

Should I try lower (3K?)

It depends on the tweeter - I'm not familiar with the Peerless you've used. However, for a typical silk-dome or metal-dome helper-tweeter, I'd probably start by crossing higher, with a single film cap of 2.2uF or so.

The other thing I might infer is that the HiQs aren't really suited for open-baffle applications, though that might also be contested. If the Pioneer 8" Bofus could work well in open-baffles, there's no reason why the HiQs shouldn't also work.
 

tnvijay

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The hi qs provide decent high end without a tweeter. I have had good experiences when pairing it with miniref and AMP camp amps. You have to stuff the area between the main cone and whizzer cone with polyfill to dampen that 2 k shout.
 

Hari Iyer

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Try baffle step compensation, the increase in mid bass may mask some of the mid frequency and the grainess of the highs.
 
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