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K-510 / K-691's ... horrible sound ... SOLVED


Emile

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Hi All,

 

Was hoping to get some advise  ... haha, before I sell these 510/691's :) 

 

Have a set of KPT-904's and think they are AWESOME ... so; bought 510's (new ones with mumps) and 691's ( equivalent to B&C DE75's).  Hooked them up via a miniDSP ... >500Hz (via a Marantz 1060) to the 510's and <500Hz to Forte I's (via a Kenwood KR-4070). Using a LR filter at 48d slope.  Using a JVC P-3030 pre-amp (which supposedly is pretty good). But ... horrible sound ... 510's just sound "tinny." "scratchy," and more like $2 speakers :(  Of course the Forte's sound pretty bad also :(  No clue if I am completely off with the 500Hz xover settings ... will try some different ones :D 

 

Hoping to get some advise :) 

 

Many thanks, Emile

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I think all is right with the universe.  The 500 Hz high pass will make anything sound tinny.

 

You could try listening with earphones and probably they will sound tinny too.

 

Let me suggest you use the other channel of our system with a 500 Hz low pass filter feeding the Forte.  When playing alone it will sound muffled and tubby.  Then place the midrange horn set to 500 Hz high pass on top of it.  Music should sound very good.

 

It would be nice to read your impressions.

 

WMcD

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10 hours ago, Emile said:

...Have a set of KPT-904's and think they are AWESOME ... so; bought 510's (new ones with mumps) and 691's ( equivalent to B&C DE75's).  Hooked them up via a miniDSP ... >500Hz (via a Marantz 1060) to the 510's and <500Hz to Forte I's (via a Kenwood KR-4070). Using a LR filter at 48d slope...But ... horrible sound ... 510's just sound "tinny." "scratchy," and more like $2 speakers :(  Of course the Forte's sound pretty bad also :(  No clue if I am completely off with the 500Hz xover settings ... will try some different ones :D 

 

 

Hoping to get some advice :)

I believe that you need to measure what you've got using a calibrated microphone.  I recommend REW. 

 

Otherwise, you're just guessing.

 

Chris

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Emile, 

First, stop panicking. Everything is going to work okay. 

 

Second, None of us have any idea what you have set up. In spite of this, some are giving advice already. 

 

Third, the us what you have done. What is the woofer section and how was it set up and how were the levels set to balance with the tweeter section. You have programed the unit to crossover at 500 Hz but there is more to it. The K510 horn is CD (constant dispersion). All CD horns require a high frequency boost.  This will be determined by measurement. Has someone provided the proper values for you to program in? There are also a number of issues regarding how to feed the source to the DSP box. Are you feeding it digitally or is there an ADC conversion going on. If so, it is critical to feed the unit a fairly hot signal (or else you will be losing many, many bits on the subsequent ADC conversion - which could explain the problem). Please try and give us an idea of the "gain structure" on your set up (do a google search for this concept). 

 

Fourth, Unless the rest of us know these answers, all our comments are meaningless. Ultimately, you will need to do some measurements as Chris advised. At least answer the above questions first. 

 

-Tom

 

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14 hours ago, Emile said:

Hi All,

 

Was hoping to get some advise  ... haha, before I sell these 510/691's :) 

 

Have a set of KPT-904's and think they are AWESOME ... so; bought 510's (new ones with mumps) and 691's ( equivalent to B&C DE75's).  Hooked them up via a miniDSP ... >500Hz (via a Marantz 1060) to the 510's and <500Hz to Forte I's (via a Kenwood KR-4070). Using a LR filter at 48d slope.  Using a JVC P-3030 pre-amp (which supposedly is pretty good). But ... horrible sound ... 510's just sound "tinny." "scratchy," and more like $2 speakers :(  Of course the Forte's sound pretty bad also :(  No clue if I am completely off with the 500Hz xover settings ... will try some different ones :D 

 

Hoping to get some advise :) 

 

Many thanks, Emile


Sounds totally like a crossover problem. Tinny like a 1" speaker! No bass or midrange, sounds like.

John Kuthe...

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4 hours ago, Chris A said:

I believe that you need to measure what you've got using a calibrated microphone.  I recommend REW. 

 

Otherwise, you're just guessing.

 

Chris


Objective measurement is definitely good if one can do it correctly, but '510's just sound "tinny"' was a subjective measurement, an opinion or report of a sound heard.

I need to get a good microphone or three!

John Kuthe...

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13 hours ago, WMcD said:

Let me suggest you use the other channel of our system with a 500 Hz low pass filter feeding the Forte

Thanks WMcD ... that's exactly how I set it up ... and got the "bad" sound. Was wondering if I should have "overlapping" frequency ranges ???

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13 hours ago, Westcoastdrums said:

It's the mini DSP. I have owned it and will say nothing else about it.   Good cheap Crossover?  Ashly XR1001

Thanks ... have heard both good and bad about the miniDSP. Thought this system was simple enough for it.  Had not heard about these Ashly's ... haha, at least you are not making me buy a Xilica :) 

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11 hours ago, Schu said:

welcome to the world of the pro line emile

Haha ... have KPT's and had several other Pro line speakers ... but never tried the 2 amp route :( 

34 minutes ago, Schu said:

Ill go to $6

Is that including shipping? :D  

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4 hours ago, PrestonTom said:

stop panicking. Everything is going to work okay.

Haha, Tom ... Thanks! That's why this beginner was asking for help from the pros :D  

 

Setup is very simple ... thought I described it, but here is more detail ...

Source is NAD CD player; analog RCA to JVC P-3030 pre-amp; analog RCA to miniDSP.

MiniDSP; nothing "set" except xover of < 500Hz to channel 1&2, feeding Forte I's via a Kenwood vintage amp. Did not disconnect any of the Forte's internal crossover.  Also, 2nd xover set to >500Hz, onto channel 3&4, feeding the 501's via a vintage Marantz 1060. (BTW, both amps sound flawless when connected directly to the preamp to the Forte's.) Pretty sure I used a LR filter on the miniDSP with a 48dB slope. Thought this setup would give me a straight level gain across the 500Hz region, but it seems to be lacking there (OK; just to my ears.) Therefore was questioning whether I should do the first xover to say <600Hz and the second to >400Hz..

4 hours ago, PrestonTom said:

All CD horns require a high frequency boost.  This will be determined by measurement. Has someone provided the proper values for you to program in?

Understand (I think :( )  Will do measurements with a Umik mike and REW.  But, sound is just too horrible now ... no measurements needed to decide it is horrible :D  No; do not have any values ...

 

Thanks, Emile

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5 hours ago, Chris A said:

I believe that you need to measure what you've got using a calibrated microphone.  I recommend REW.

Yes, will do. Have a Umik and REW ready to go. But ... sound is so bad :(  was hoping to get closer first :D 

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1 hour ago, JohnKuthe said:

Sounds totally like a crossover problem. Tinny like a 1" speaker! No bass or midrange, sounds like.

Thanks John. Yeah ... "tinny" and "scratchy" like a 1" speaker :( Was thinking I might have to do a (for example) <600Hz and >400Hz xover ... but really have no clue :( 

59 minutes ago, JohnKuthe said:

Objective measurement is definitely good if one can do it correctly, but '510's just sound "tinny"' was a subjective measurement, an opinion or report of a sound heard

Was just my observation after I hooked it up :( Will measure ... was just trying to get a bit closer using my ears :) 

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19 minutes ago, Emile said:

Yes, will do. Have a Umik and REW ready to go. But ... sound is so bad :(  was hoping to get closer first :D 

No need.  Just set the crossover at about 600-800 Hz (about where the K-510 horn begins to control its polars well and the Forte bass bins can easily reach).  Completely disconnect your passive crossovers in your Fortes and bi-amp the K-510/K-691 and Forte bass bin (only).  I'd set the K-510 channel gains at about -3 dB.  Then run a sweep from 10 Hz to 20  kHz with the microphone at 1 metre in front of the K-510/Forte bass bin (aligning the K-510 on top where you want it to be).  PM me and I can help you dial-in the miniDSP settings to flatten its overall response and fine tune the delay and crossover filters. 

 

Chris

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1 hour ago, Chris A said:

No need.  Just set the crossover at about 600-800 Hz (about where the K-510 horn begins to control its polars well and the Forte bass bins can easily reach).  Completely disconnect your passive crossovers in your Fortes and bi-amp the K-510/K-691 and Forte bass bin (only).  I'd set the K-510 channel gains at about -3 dB.  Then run a sweep from 10 Hz to 20  kHz with the microphone at 1 metre in front of the K-510/Forte bass bin (aligning the K-510 on top where you want it to be).  PM me and I can help you dial-in the miniDSP settings to flatten its overall response and fine tune the delay and crossover filters. 

Chris,

Thaks a million :D  Will take you up o your offer :)  But first ??? see below

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Tried some different crossover settings ...

 

First, to make sure (something) is working, I bypassed the xover settings on the L/R, output 3&4 to the Forte's.  Haha; great sound (obviously as before).  Reset the low Forte xover to 800Hz ...  not great. Added the 510 high xover at 700Hz.  Something is wrong ... trying to describe it ... this applies to both speakers ... sounds like it is playing an old record with a very bad needle ... single tones sound like they are spread over more than just a single tone, resulting in an almost scratchy sound ... sounds like they are not synchronized ... ???? (And yes; tried it without the miniDSP and all is fine :( ).

 

Anyway to test the 510's without this miniDSP?  Guess I could try some passive crossovers ... but all those have a slow 12dB/oct slope ... thought I needed 48dB/oct.

 

????? Thanks, Emile

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  • Emile changed the title to K-510 / K-691's ... horrible sound ... SOLVED

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