I need some help please ...incl. from the Master himself :-)

Florian · « **on:** 20 Apr 2005, 01:04 pm »

Hello

Here is a picture of the great RM30's in my newly made room. (still work in progress).

I also received my Tact unit which worked wonders on the big and small Maggies, and big wonders on the RM30's- The problem is that now i changed the room and the RM30 frequency response in my room looks like spagettie.

Now the tact can correct this but i need to set a targer curve. And thats wrere my problem lies. How should i set it, or whats the optimal response of the RM30 ?

Here is a picture of the current response and the curve i set.

Can Big B or other folk please tell me what the RM30's curve is supposed to look like from a perfect point?

Thanks

-Flo

ctviggen · « **Reply #1 on:** 20 Apr 2005, 01:36 pm »

Is that amplitude v. frequency response already adjusted by the TACT? If not, that's a great room. My response, even with 6 Realtraps, looks way, way, way worse than that.

Florian · « **Reply #2 on:** 20 Apr 2005, 01:41 pm »

Thats all uncorrected yet.

-Flo

Florian · « **Reply #3 on:** 20 Apr 2005, 01:52 pm »

My biggest problem is the bass. With the jolida the bass is powerfull and never overoaded. The tact with my correction seems to put more info into all the drivers and make it sound very very detailed with awsome seperation but overpowering but self canceling bass ?!!?

-Flo

zybar · « **Reply #4 on:** 20 Apr 2005, 01:55 pm »

Florian,

You are better off joining the TacT groups in Yahoo and getting asistance there.

Although there are a few of us who use or did use TacT gear with VMPS speakers, this really isn't the place for the guidance you need.

Some general concepts:

1. Keep playing with speaker placement until you get as good as measurements as possible. TacT is a tool, not a magic elixir. From your screen capture, you have a ways to go!

2. Try not to correct the dips too much. Some say you need to stay below 0db's, but I personally feel you can have 1-5db's correction depending on the frequency point and width of the correction.

3. If necessary, lower your entire correction curve so you meet item number two.

4. Don't try and correct below what your speakers are capable of. Probably going to get flamed a bit here, but with the 30's you probably want to roll off the correction around 40Hz. Not sure where that huge dip is, but my guess is it is somehwere around there. All of us who measured VMPS speakers found that the passive radiator drops off very quickly...

Hope this help a bit.

George

JoshK · « **Reply #5 on:** 20 Apr 2005, 02:15 pm »

I have no experience with the TACT but here is what I'd offer in the way of advice.

Zybar is right with his suggestions, play with room placement some, but assuming you have them where you want them I would suggest the following course of action.

- Have you tuned the PR's to get the best sound? I would try taking some more putty off the PRs and remeasuring to see if the lower bass range changes at all. Comparing the two will shed a little insight but still trust your ears to make sure you are making two wrongs trying to be a right.
- You obviously have some room gain around 80-100hz, this is normal and will be where the TACT trims off the top to make for flatter bass response. You may play with bass traps if you have them and see how the measurements change.
- You have what looks like some reflection issues in the mids as well, hence the large hump in the middle. Try placing absorbtion/diffraction material in the first reflections and see how the measurements change.If all this fails then let the TACT trim that down.
- I am guessing you need to turn up the mid control slightly based on those measurements, which may require turning up the tweet control too, although a bit less so.

Take your time, listen, enjoy, play around and experiment.

ctviggen · « **Reply #6 on:** 20 Apr 2005, 02:41 pm »

Bass traps are still valuable because of what an amplitude v. frequency response graph doesn't show you -- which is decay. This week, I'm putting in my RM40 upgrade and plan to take some measurements using ETF. I'm going to take the measurements with no Realtraps and with Realtraps. I'm going to take amplitude v. frequency response and decay graphs so that I can see what the differences are. These graphs should show an improvement in decay. I'm also going to use such graphs to dial in the sub/RM40 crossover information.

Brian Cheney · « **Reply #7 on:** 20 Apr 2005, 03:30 pm »

Treat the wall behind and beside the speakers with Sonex or similar material and add some bass traps. Your correction will then have very little to do. The RM30 measures +/- 2.5 dB from 35Hz to 30 kHz. You will hae to add a sub to get first octave bass.

B

Brian Cheney · « **Reply #8 on:** 20 Apr 2005, 03:31 pm »

Treat the wall behind and beside the speakers with Sonex or similar material and add some bass traps. Your correction will then have very little to do. The RM30 measures +/- 2.5 dB from 35Hz to 30 kHz. You will hae to add a sub to get first octave bass.

B

Jose R. · « **Reply #9 on:** 20 Apr 2005, 09:43 pm »

Quote from: ctviggen

Bass traps are still valuable because of what an amplitude v. frequency response graph doesn't show you -- which is decay. This week, I'm putting in my RM40 upgrade and plan to take some measurements using ETF. I'm going to take the measurements with no Realtraps and with Realtraps. I'm going to take amplitude v. frequency response and decay graphs so that I can see what the differences are. These graphs should show an improvement in decay. I'm also going to use such graphs to dial in the sub/RM40 crossover information.

Hi Bob

I will be interested to see whether you can measure any change in the frequency response with the room treatment. I did a lot of measurements a while back when putting in absorption panels and diffusors. The sound did change audibly but the measurements did not really show much change.

Regards

Jose

Jose R. · « **Reply #10 on:** 20 Apr 2005, 09:56 pm »

Quote from: Florian

Hello
I also received my Tact unit which worked wonders on the big and small Maggies, and big wonders on the RM30's- The problem is that now i changed the room and the RM30 frequency response in my room looks like spagettie.
Now the tact can correct this but i need to set a targer curve. And thats wrere ...

Hi Florian

As George says, the TactAudioUsersGroup forum at Yahoo groups is a good source of information.
I have the RM30C's and the Tact 2.2x. I have done a lot of measurements of the speakers in different positions. In general, you should position them where they give you the focus and soundstaging that you seek. Then do measurements and correct for peaks (and to a lesser extent nulls). Drop your target curve so that there is limited upward correction.
You will never get a straight line with the Rm30's or any other speaker at the listening position - don't let ot worry you.
It is tempting to turm up the mid pots to try to get rid of some nulls between 400-700Hz - in my expereince it is not beneficial. The main effect is a rise in the SPL curve above 3000Hz and the sound becomes a bit harsh.
You will need to play around with different curves to see what sounds best in your room. I use a curve with a bass boost of about 2dB from 40Hz tapering down to 500Hz then flat to about 4000Hz, then tapering down gradually to -2dB at 20KHz.
Have fun

Jose

zybar · « **Reply #11 on:** 23 Apr 2005, 08:56 pm »

Florian,

Good to see that you joined the TacT forum and you are already getting many responses to your posts.

From my personal experience, the TacT preamp when used properly can make a very substantial improvement on the VMPS speakers (or most speakers for that matter).

Take your time and enjoy.

George

Florian · « **Reply #12 on:** 24 Apr 2005, 01:12 pm »

Thanks everyone. I also noticed a big problem and its unbelieveable how much stuff i had to fix already on a new speaker. But the sound is worth it.
I noticed on the tact that the left speaker always had a huge dip in the mid-lower regions. Guess what ?!?

The wires connecting to one of the actice 6 1/2 drivers were broken off. I couldnt believe. Everytime when the 10" pshed it compressed the air and made the fronts move too so i thought it was fine. Well i took the 10" out and nothing moved. the darn thing was broken off. Well i finally fixed it and gained 10db in lost regions !! Argh.......i have spent weeks on this speaker....hrs hundreds of hrs.

-Flo

-No matter how you ship it, something can always happen.

ctviggen · « **Reply #13 on:** 24 Apr 2005, 01:15 pm »

Ah, it seemed to work when you were in the US. If that's the case, then it broke during shipment, which I don't think is unusual. The boxes for my RM40s looked terrible when I got them to my place -- I'm surprised the speaker worked at all.

Florian · « **Reply #14 on:** 24 Apr 2005, 01:23 pm »

Who knows what happend in shipment.
Maybe if Brian could connect the cables to the chassy with some holding glue and use different connectors it would be great?

-Flo

Rocket · « **Reply #15 on:** 24 Apr 2005, 01:50 pm »

Hi,

It probably happened during shipping to germany. After all it has to travel a looong way.

Regards

Rod

Florian · « **Reply #16 on:** 24 Apr 2005, 01:54 pm »

Properbly. I am just glad i figured it out before i would have turned myself into a straight jacket

Brian Cheney · « **Reply #17 on:** 24 Apr 2005, 04:32 pm »

I cannot recall a wire breaking off a driver. We run several QC tests incl a battery check to catch such things as inoperative woofers.

For the past several months I have taken each pair of RM series speakers home to my soundroom for a "real" QC with tuning and damping adjustments made for the customer.

Florian · « **Reply #18 on:** 24 Apr 2005, 09:57 pm »

I am sorry Brian, this must have been during the shipment.

-Flo

warnerwh · « **Reply #19 on:** 24 Apr 2005, 10:07 pm »

Anybody who has shipped many pieces of equipment knows what some of it looks like when it gets there. It's no less than incredible. I've seen stuff that looks exactly like it was rolled down a rock cliff, no exaggeration. A friend who worked at Fedex said that they require packages to be able to take a 10 foot drop and land without damage.