Really great forum. It made me build Gainclone based on LM3875 which sounds amazing to me. I believe in the “Less is more” approach.
Lately after building a Gainclone and mod’ing my CDP I started hearing things I didn’t before. I’m getting a totally different (much better) soundstage (width and dept) and I’d like to improve on that. I think it has a lot to do with the speaker’s phase response. So I’m wondering if I can improve the current speakers filters. Right now they have the sec. order LC filters on both speakers and no Zobel. The Cap on the HF speaker is paper type and the LF cap is electrolytic Non-Pollar type.
The only thing I did that improve drameticly the soundstage was placing weather strips next to the HF speacker wich helped a lot with the focus and the spaciousness of the soundstage.
I don't want to change the drivers or the cabinet.
I’d really appreciate your suggestions.
Those are the speakers I have. I’m very happy with the tonal balance.
http://www.yamaha.ca/av/speakers/PDMSeries/NS200.asp
/Greg
Lately after building a Gainclone and mod’ing my CDP I started hearing things I didn’t before. I’m getting a totally different (much better) soundstage (width and dept) and I’d like to improve on that. I think it has a lot to do with the speaker’s phase response. So I’m wondering if I can improve the current speakers filters. Right now they have the sec. order LC filters on both speakers and no Zobel. The Cap on the HF speaker is paper type and the LF cap is electrolytic Non-Pollar type.
The only thing I did that improve drameticly the soundstage was placing weather strips next to the HF speacker wich helped a lot with the focus and the spaciousness of the soundstage.
I don't want to change the drivers or the cabinet.
I’d really appreciate your suggestions.
Those are the speakers I have. I’m very happy with the tonal balance.
http://www.yamaha.ca/av/speakers/PDMSeries/NS200.asp
/Greg
You can try better quality capacitors.
Do not add a Zobels, you'd need to redesign the c/o.
Other tweeks without major changes are :
1. Experiment with lengthening the port to detune it for lower
bass. (reducing diameter also works if you run out of length).
2. Damping the cabinet with cheap vinyl floor tiles.
3. Adding sand to the bottom of the speaker.
4. Upgrading the acoustic damping in the speaker, e.g. if
its cheap Dacron, BAF, Polyfil to foam lining the cabinets.
5. Use blutack or similar to bed the drivers into place.
6. Blutack the speaker to a 10" x 10" concrete slab ( fairly
easy to improve its appearance) and use 3 cones blutacked
to the underneath for spiked floor coupling.
7. If you floor tile the cabinet use some bits on the bass unit
chassis to damp it, specifically the chassis "legs".
8. Solder any push on connectors, you don't need to remove
the connectors, just solder everything.
9. Blutack the terminal connector into place.
10. Glue a block of quality acoustic foam to the back of the
bass driver.
sreten.
Do not add a Zobels, you'd need to redesign the c/o.
Other tweeks without major changes are :
1. Experiment with lengthening the port to detune it for lower
bass. (reducing diameter also works if you run out of length).
2. Damping the cabinet with cheap vinyl floor tiles.
3. Adding sand to the bottom of the speaker.
4. Upgrading the acoustic damping in the speaker, e.g. if
its cheap Dacron, BAF, Polyfil to foam lining the cabinets.
5. Use blutack or similar to bed the drivers into place.
6. Blutack the speaker to a 10" x 10" concrete slab ( fairly
easy to improve its appearance) and use 3 cones blutacked
to the underneath for spiked floor coupling.
7. If you floor tile the cabinet use some bits on the bass unit
chassis to damp it, specifically the chassis "legs".
8. Solder any push on connectors, you don't need to remove
the connectors, just solder everything.
9. Blutack the terminal connector into place.
10. Glue a block of quality acoustic foam to the back of the
bass driver.
sreten.Thanks Sreten,
Regarding damping with the floor tiles: I once did it on my CDP housing and after a while it all started coming off. Do you use a special glue or just the glue that's already on the back ot the tiles.
I'll change the caps for sure. I had problems with the base reproduction in the livingroom. I guess the hight of the woofers is such that because of the standing waves in the room I can hear the base well but I have to be standing. In the normal sitting position the base is not that great and I don't want to just bump it up. I need to do something so that the SW distribution changes. Maybe if I rais the speakers up it'll soud better. I found out that if I mont them on spikes the base is very week and if I have spikes at the front but not at the back is much better. I have to keep experimenting I guess.
From reading about filters I thought that Zobel on the base would be a good thing, but I don't have any experiance there.
Thanks again for the suggestions!
/Greg
Regarding damping with the floor tiles: I once did it on my CDP housing and after a while it all started coming off. Do you use a special glue or just the glue that's already on the back ot the tiles.
I'll change the caps for sure. I had problems with the base reproduction in the livingroom. I guess the hight of the woofers is such that because of the standing waves in the room I can hear the base well but I have to be standing. In the normal sitting position the base is not that great and I don't want to just bump it up. I need to do something so that the SW distribution changes. Maybe if I rais the speakers up it'll soud better. I found out that if I mont them on spikes the base is very week and if I have spikes at the front but not at the back is much better. I have to keep experimenting I guess.
From reading about filters I thought that Zobel on the base would be a good thing, but I don't have any experiance there.
Thanks again for the suggestions!
/Greg
Re floor tiles,
use the cheapest and thinnest you can find, these are the best.
I use a small wallpaper roller, never had any problems.
Re bass :
Very unusual description, usually bass is better nearer room boundaries,
and notoriously weak in the centre of the room & half room hieght.
Spiking shouldn't affect bass balance the way you describe,
in my experience, what type of floor do you have.
Re Zobels :
make crossover design easier but not the other way round.
sreten.
use the cheapest and thinnest you can find, these are the best.
I use a small wallpaper roller, never had any problems.
Re bass :
Very unusual description, usually bass is better nearer room boundaries,
and notoriously weak in the centre of the room & half room hieght.
Spiking shouldn't affect bass balance the way you describe,
in my experience, what type of floor do you have.
Re Zobels :
make crossover design easier but not the other way round.
sreten.sreten said:Re floor tiles,
use the cheapest and thinnest you can find, these are the best.
I use a small wallpaper roller, never had any problems.
Re bass :
Very unusual description, usually bass is better nearer room boundaries,
and notoriously weak in the centre of the room & half room hieght.
Spiking shouldn't affect bass balance the way you describe,
in my experience, what type of floor do you have.
Re Zobels :
make crossover design easier but not the other way round.
I have a thin hardwood floor and no cement/concrete underneath and below is the basement.
It was very discouraging when I installed the speakers the first time (no base at all) until I found out what was happening. Regarding the spikes, I guess it decouples the speakers from the floor thus the floor resonates less, I don't really know.
GregGC said:
Ductseal should be available at any HVAC supplu house -- there are substitutes, but i haven't found anything quite as suitable.
Here is a pic of an RS 40-1197 -- some should be added to the basket legs too (but the 1197 doesn't have much in the way of basket legs.
dave
Attachments
Erm... your floor description gives outstanding qualities to a
thin layer of hardboard.
So I assume you have a suspended wooden floor ?
My best results with a suspended wooden floor and 1" of carpet
& underlay was a homemade speakerstand with 3 4" chipboard
screws driven through everything into the floorboards.
The speakers where blutacked to the stand and using a finger
is was impossible to wobble them, they felt architectural.
Bass was lighter but bass/mid had far more attack and detail,
sreten.
thin layer of hardboard.
So I assume you have a suspended wooden floor ?
My best results with a suspended wooden floor and 1" of carpet
& underlay was a homemade speakerstand with 3 4" chipboard
screws driven through everything into the floorboards.
The speakers where blutacked to the stand and using a finger
is was impossible to wobble them, they felt architectural.
Bass was lighter but bass/mid had far more attack and detail,
sreten.
planet10 said:
Hi p10,
0 - never occurred to me, my speakers will soon becoming
apart, again.... does DS harden or remain flexible ?
11 - true, but then your into crossover layout etc also.
12 - very difficult to do through the bass unit cutout for these
speakers, and there is no other access, though I agree two or
three horizontal battens subtlety placed would help.
******s up using wall damping easily though........
sreten.
GregGC said:
Just conjecture but the effects of spiking may depend on where
the joists for the floor are. IMO with a wooden floor blutacking
is better then spikes generally.
A concrete slab is probably not necessary, especially if you go
for the sand, but direct blutack to the floor is the first thing I'd try.
I'd go for a spot near / above the joists.
sreten.
You should also phase off (or is it scamfer in english?) the bass drivers cut out in the cabinet, as well as making sure the cabinet is absolute airtight by giving the inside a generous lacquer or painting, and using duct seal in the joints. Some use silicone for that but one should be aware that the fumes from that disintigrate synthetic rubber and other plastics over time. Bracing the front plate might also be a good idea.
catapult said:
I'll have to dig out a pack, but IIRC it had both US & Canadain addressed on it.
faustian bargin found an on-line source for it:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=23468&highlight=
Mortite & rope caulk are similar to duct seal -- i've used rope caulk but don't like it as well -- it is more convienient for making gaskets thou.
dave
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