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K402 TAD4002 and Peavey FH1 active blend

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On 12/21/2019 at 12:02 AM, noviygera said:

>>The 1504-4s are crude and tough

Meaning, the fidelity is suffering?

I'm using my FH1s from 70-250hz.  I added a bit of felt damping sheets to the doghouse -- it had no damping at all.

 

Is the JBL 2226H a significant improvement over the Peavey driver in terms of fidelity in home use? Seriously considering to try other woofers but not for the sake of trying. The other woofers mentioned here -- what improvement do they bring over the stock 1504 driver? 

 

Significantly less harmonic distortion.  When I curved the set I built, harmonic distortion exceeded the fundamental below 100 Hz.  I was outside, but I can't believe I ever exceeded 100 dB.  I wanted to install a pair of Bob"s cast frame K-33 replacements, but never did.  I gave these to the church and was not the only person running them.  I wanted bulletproof. 

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On 1/23/2020 at 4:38 PM, Delicious2 said:

 

wow, that is quick.  Looks like foam stuffing rather than any kind of panel damping.  Just stuffed in there behind driver?  Not attached to anything.  While I have my FH1s apart I'd like to do any easy/prudent stuffing/damping/tweaking

 

Hi,

 

I'm using FH1s in my system currently loaded with K33 (probably will soon switch to Kappa 15C).

I tried damping the back chamber and these are my results:

started by lining all internal panels with auto-sticking bitumen sheets (sold for car audio tuning) I guess the brand was SinusLive from Germany. I then covered all internal panels with eggs-crate foam (quality German stuff, not cheap light foam from China); I foolishly thought because it was ""just foam" and it was just lining the panels it wouldn't impact the back chamber's effectiveness, but boy was I wrong! The treated FH1 had seemingly NO output, like the driver was stuck in glue! TERRIBLE!!! 😞

I then proceeded to remove all the foam - just leaving it on one of the horizontal panel that is facing the removable bottom panel, since that's the only place where standing waves can occur. That worked, and allowed the driver to do its job while removing a lot of the woody resonance and spurious vibrations (when you are sitting in semi-nearfield, you sometimes hear the cabinet "singing along" even with FH1; in a huge room sitting far I'd think it's less annoying). Sometimes I have the feeling the PERCEIVED output might be 1 dB less than untreated, but it's probably just hearing less resonances and distortions, and in an active setup wouldn't matter much anyways. Globally very happy as to how it turned out. Hoping it will work as good with 15C drivers in there.

 

Whatever you choose to do, DO NOT over damp the back chamber, and of course (you know that already) do not touch the horn path.

 

In my system the fH1s are used with John Allen A55G mid drivers, EV SM120 mid horns, Beyma CP25 tweeters; active 24dB at 400Hz and passive 6Khz - sounds great even if I wouldn't compare it with some K402 and big high end 2" drivers.

 

I use two high end Focal active subs, and I tried crossing them over at 80Hz but it made the bass quite slow; horn subs are not an option so I ended up high-passing the FH1s at 40Hz (just to avoid wasting amp power on those frequencies ) and the subs low-pass is around 60Hz, using the subs internal filter; in my room the overlap it creates with the fH1 gives the most agreeable transition from horn mid bass to direct radiating subs.

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6 hours ago, Rolox said:

 

...I then proceeded to remove all the foam - just leaving it on one of the horizontal panel that is facing the removable bottom panel, since that's the only place where standing waves can occur. That worked, and allowed the driver to do its job while removing a lot of the woody resonance and spurious vibrations (when you are sitting in semi-nearfield, you sometimes hear the cabinet "singing along" even with FH1; in a huge room sitting far I'd think it's less annoying). Sometimes I have the feeling the PERCEIVED output might be 1 dB less than untreated, but it's probably just hearing less resonances and distortions, and in an active setup wouldn't matter much anyways. Globally very happy as to how it turned out. Hoping it will work as good with 15C drivers in there.

 

Whatever you choose to do, DO NOT over damp the back chamber, and of course (you know that already) do not touch the horn path.

 

In my system the fH1s are used with John Allen A55G mid drivers, EV SM120 mid horns, Beyma CP25 tweeters; active 24dB at 400Hz and passive 6Khz - sounds great even if I wouldn't compare it with some K402 and big high end 2" drivers.

 

I use two high end Focal active subs, and I tried crossing them over at 80Hz but it made the bass quite slow; horn subs are not an option so I ended up high-passing the FH1s at 40Hz (just to avoid wasting amp power on those frequencies ) and the subs low-pass is around 60Hz, using the subs internal filter; in my room the overlap it creates with the fH1 gives the most agreeable transition from horn mid bass to direct radiating subs.

 

Welcome Rolox!  Excellent first post - nothing like relating your real hands on experiences.👍.  I'll also be installing some 15cs soon in my FH1s and may take some measurements before and after.  What about some of this 8mil "foam" self adhesive insulating pad on that horizontal panel? 

https://www.amazon.com/dp/B01KAD24RI?psc=1&ref=ppx_pop_dt_b_product_details

 

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19 hours ago, Delicious2 said:

 

Welcome Rolox!  Excellent first post - nothing like relating your real hands on experiences.👍.  I'll also be installing some 15cs soon in my FH1s and may take some measurements before and after.  What about some of this 8mil "foam" self adhesive insulating pad on that horizontal panel? 

https://www.amazon.com/dp/B01KAD24RI?psc=1&ref=ppx_pop_dt_b_product_details

 

Actually, I'm not really new here: I was very active on this forum at some point (I think almost 20 years ago? is that even possible? I think so) but then I became member of other forums and life got in the way... and I lost access to my account... I was young however and had much less experience and knowledge than now (all is relative, I'm no engineer of course, far from it) and I don't know if there's much I wanna save from that period. My nickname was Shock-Late 🙂 

 

About that foam: it's hard to tell from the link. If you wanna deaden the wood panels, you need something dead and heavy and sticky that will bond with the wood. I'm not sure this is dense enough for wood. But maybe?... it will however be very hard to remove so I'd go for something you're really sure of. You won't get to try different things...

 

Here's the bitumen sheets I've used; I'm located in Europe, I don't know if it's worth paying the shipping to the US, you can probably find something similar over there:

 

https://www.befr.ebay.be/itm/Sinuslive-20er-Pack-ADM-Bitumenmatte-Dammmatte-Selbstklebend-22-45-EUR-m/153765174866?hash=item23cd1e5e52:g:zFoAAOSwFiNd-MX8

 

It's very heavy and yet is easy to cut even with scissors. Extremely easy to use, no smell, no "cooking" necessary. You can apply two layers where you find it necessary.

(You will need two packs for two FH1, if you decide to order some)

 

I can't find the foam, it is I guess 40mm thick eggs crate acoustic foam with a peel-on sticky back face, it sticks very strongly; you need a quality foam of good density.

 

Here's a picture of my "LaScala on steroids" :-)

 

IMG_2258.jpg

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On 1/31/2020 at 2:46 AM, Rolox said:

 

 

 

In my system the fH1s are used with John Allen A55G mid drivers, EV SM120 mid horns, Beyma CP25 tweeters; active 24dB at 400Hz and passive 6Khz - sounds great

-I am surprised that you did not simply mount the BEYMA CP 25 straight  into the center of the EV SM120 , these were designed to mount the  EV ST350 right into the center -

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23 minutes ago, Randyh said:

-I am surprised that you did not simply mount the BEYMA CP 25 straight  into the center of the EV SM120 , these were designed to mount the  EV ST350 right into the center -

I'm sorry to say that the Beyma CP25 tweeter is a large object relative to the acoustic frequencies at and even below the tweeter/midrange crossover frequency--nominally 5 kHz.  A full wavelength at 5 kHz at 23 C (73 F) is about 2.72 inches (69 mm).  The CP25 body is significantly larger than even a full wavelength at 5 kHz: 

 

CP25%20dimension%20drawings.jpg

 

So when you place the full body of a CP25 into the mouth of a lower frequency horn, you're acoustically obstructing the lower frequency waves being emitted by the lower frequency horn, which causes fairly complex mouth bounce and lobing issues. 

 

It's better to surround the entire body and rear of the CP25 (leaving only the mouth of the tweeter uncovered) with acoustically absorbent material if you are placing it into a midrange horn mouth.  I would recommend at least 1" thick absorbent material (2.5 cm)...or alternatively avoid placing the CP25 into the mouth of a midrange horn. 

 

Chris

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It strikes me how similar in appearance the EV SM120 is to the TAD TH-4001, at about 1/20th of the price!

 

Also noticed the high tech isobaric insulating devices under the horn. Wonder what NASA would pay for those?

 

I’ll have to wait until spring when the snow melts revealing the annual crop of insulators that flourish around the pond down the road.

 

 

EC34933B-2AE4-4BCE-99FB-C7787E0D5DC0.jpeg

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20 hours ago, Randyh said:

-I am surprised that you did not simply mount the BEYMA CP 25 straight  into the center of the EV SM120 , these were designed to mount the  EV ST350 right into the center -

In fact they were not: the ST350 were hanging UNDER the SM120 horn, indeed attached to those holes on the sM120 lips.

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15 hours ago, geoff. said:

It strikes me how similar in appearance the EV SM120 is to the TAD TH-4001, at about 1/20th of the price!

 

Also noticed the high tech isobaric insulating devices under the horn. Wonder what NASA would pay for those?

 

I’ll have to wait until spring when the snow melts revealing the annual crop of insulators that flourish around the pond down the road.

 

 

EC34933B-2AE4-4BCE-99FB-C7787E0D5DC0.jpeg

Hahaha yes, the high-tech insulators ^^

 

I had to raise the high pass horns due to a change in sofa (I kid you not) so that my ears would still be in the right eight. so I bought hockey pucks. Works wonders - but if you look closely you will see there IS an audiophile-approved, specially made isolator between the hockey pucks and the top bin 😉

 

About the SM120: they are WONDERFUL. Wide open and smooooooth, and even in semi near-field (I sit about 8 feet from my speakers!) they throw a wide and enveloping soundstage, and no shout, no honk. With the John Allen A55G it's fantastic.

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44 minutes ago, Rolox said:

In fact they were not: the ST350 were hanging UNDER the SM120 horn, indeed attached to those holes on the sM120 lips.

you would be blind not to see it   the SM120 horn was specifically designed  by EV  to mount  an EV ST350 , right in the middle of the horn , the bracket and screw holes are built right into the horn frame -

 

https://www.hifi-selbstbau.de/images/stories/chassis/Sentry_M1829+SM120A/SM120A EDS.pdf

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10 hours ago, Randyh said:

you would be blind not to see it   the SM120 horn was specifically designed  by EV  to mount  an EV ST350 , right in the middle of the horn , the bracket and screw holes are built right into the horn frame -

 

https://www.hifi-selbstbau.de/images/stories/chassis/Sentry_M1829+SM120A/SM120A EDS.pdf

Nope. The mounting holes in the horn were used to mount a frame that makes the horn more rigid and holds the tweeter hanging LOWER. As far as I know, the tweeter was NEVER mounted on the horn itself.

 

1500885-electrovoice-sentry-iv-rare-and-vintage-in-excellente-condition-no-shipping.jpg

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