Speaker tuning DIY

[Esra]

Wondered if anybody tried DIY tuning his speakers and do some experiments?I recently played with some greese filter material out of fleece and placed some of it into the cabinet departments of my MA RX6 just to see how it behaves with different amounts of it.I found this very interesting since I achieved quite different results giving the possibility to finetune the speakers to your likes a bit.Next I will try with some other material like Rockwool.

What do you think?Since it sounds good and shouldn´t harm the speakers i think it is a relativ simple and cheap way to try for optimizing the speakers to your likes.I found some places in the cabinet which are not damped with the original material which besides could also be done with more care imo.

 

[Vladimir]

I've done such experiments with speaker damping material myself.

Best results with two materials - natural very very fine wool for the standing waves and bitumen sheets on walls to cure vibration. The logic behind this is simple. You want your damping material to have highest conversion of moving air into heat due to friction and for your wall resonance you want the most inert material.

I've also filled bottom bits with sand bags and ti helps the stability of the whole box overall making it inert and less reactive to floor resonance, however it significantly reduces the volume of the chamber thus changing the speaker cabinet tuning, so it is a hit a and miss with this one.

Rockwool was best for acoustic suspension cabinets (closed type).

 

[Esra]

Nice Vlad.

Guess what I have done 10 minutes ago? I placed some Bitumen sheets to the uncovered areas in the cabinet and will cut them right now to fit them perfectly.Then I will fix them with double sided tape.The fleece I used should have nearly the same effect as fine wool but these should only effect high freq. Bitumen more for low freq..I had just the same thoughts which you described obove turning as much energy into heat and get resonances as low as possible within the cabinet.Think it´s just to find out the balance of the material itself and the amount of it.Reducing volume of the cabinet,ex. bass cabinet could help to intervene most effectively the performance ,just to be carefull not to shift the balance too much.

 

[Vladimir]

Awesome. :clap: Don't spare the bitumen on the front baffle (from the back side). It's where the most tectonic resonances occur.

Another good tweak that resolves front baffle reflections for your midrange and high frequency drivers is felt sheets. Like in this Dunlavy SC-V. I tried that on my AR-11s, also tried with some neopren from old mouse pad (inspired by the JBL XPL-200) and couldn't really hear an improvment that much, but I guess it depends on design. B&W Matrix had those fuggly plastic skins that reduced surface resonance but I couldn't go that far changing the apearance of my speakers.

I guess the proper way to do it is using microphone and FR analyzer but I had my fun just by tuning with my own flawed hearing. Fluke 810 vibration tester also helps, just $9000 retail.

I wish if Richard Allen could give us few tips, considering he is the designer of EB Acoustics speakers and fellow member.

 

[drummerman]

I re-wire (hard wire) internally every speaker I buy.

I usually add thin cross braces.

In addition I place damping materials, not unlike bitumen sticky pads inside the side panels and at the rear of the magnets.

I normally leave the wooll or foam alone.

This all may sound like it would change the interior volume of the speakers drastically but it doesn't.

I also usually block the ports as I can't stand port farting and the wrong sounding, time delayed bass.

Ears quickly adjust to the apparent 'lack' of bass and removing the port blocks after a while just makes it plain clear how bad and slow ported bass can be.

This all depends on the speakers of course but give me a good, fast IB anytime.

Finally I place heavy duty stainless steel/rubber doorstops on top of speakers which rest on polypods on their respective stands.

regards

 

[Vladimir]

@drummerman

Those are excellent tweaks and bit more advanced than usual.

I converted 2 ported speakers into closed type and adjusted them with DSP but the little ones (Wharfedale Diamond II) cooked the voice coils (both mid/bass drivers). I have no idea is it because I added extra stress to the driver with the cabinet compression or is it because I stopped the cooling with the ported system. Maybe I just pushed them harder to get the same amount of bass with my amp.

Any theories?

 

[Esra]

Finally I place heavy duty stainless steel/rubber doorstops on top of speakers which rest on polypods on their respective stands.

regards

:O I thought i was mad but nice to see there are more of my species

Nice method to check resonances i learned from a friend is with a bottle of water top on the speakers.He also explained me he could read roughly from water motion which freq. have to be damped more :doh: but i forgot.He also lets stay the bottle on top for further damping ,crazy he?

 

[drummerman]

Finally I place heavy duty stainless steel/rubber doorstops on top of speakers which rest on polypods on their respective stands.

regards

:O I thought i was mad but nice to see there are more of my species

Nice method to check resonances i learned from a friend is with a bottle of water top on the speakers.He also explained me he could read roughly from water motion which freq. have to be damped more :doh: but i forgot.He also lets stay the bottle on top for further damping ,crazy he?

Well, I wouldn't quite go that far . A few people commented on the door stops, not knowing what they were and thinking they are part of the speakers/ a driver. - They match the stands so all looks as it would belong together.

@Vladimir

Ports help damp drivers if the speaker has been so designed to to originally. Its easier to over drive a blocked port speaker as efficiency takes a dive.

I listen at low to medium levels with only occasionally turning it up so it doesn't really affect my listening (other than in a positive way as described previously).

regards

 

[wilro15]

Wow, I had now idea people did this sort of thing! Not sure I am ready to take apart my speakers and start messing inside, but I like the other ideas.

 

[Vladimir]

In my latest tweak I added a periscope port tube to simulate transmission loading. I did this only to one speaker, the one that is in the corner 40-50cm away from walls. The other one is fine with its bass and it isn't annoyingly boomy because it has no other walls around it except the back.

The plastic knee tube has a sponge tube from pipe insulations (small bit presented in the images) to connect it with the speaker port. The electricians tape is just to keep the tubes straight, not much weight to them. Since I'm renovating the house I have plenty of leftover materials from plumbing, insulation etc. to play with.

This is a simple reversable experiment which gave me better results than with JRiver DSP or stuffing foam bangs in the port to iron out the port bass hump at 90-100Hz. I haven't played with tube length, just with the sponge tube fitting. I can also stuff the tube with wool or other speaker dumping material to convert air movement into heat outside of the speaker cabinet.

With all the corner boom reduced I get much clearer midrange and imaging, as well as better centering of the soundstage. Not perfect, just better and I haven't even began refining the system. It's more about having fun to be honest.

Click on images to zoom.

 

[james_LR90]

I have removed all the foam wadding from inside my speakers and I should in the near future be lining the inside of the cabinets with steel plate. Also going to rewire with some modern, thicker wire.

 

[Vladimir]

I have removed all the foam wadding from inside my speakers and I should in the near future be lining the inside of the cabinets with steel plate. Also going to rewire with some modern, thicker wire.

Have you considered also bitumen sheets? They are quite effective and easy to work with.

 

[james_LR90]

I have removed all the foam wadding from inside my speakers and I should in the near future be lining the inside of the cabinets with steel plate. Also going to rewire with some modern, thicker wire.

Have you considered also bitumen sheets? They are quite effective and easy to work with.

I hadn't to be honest. I know the steel lining mod has been applied to the same speakers as mine before with noticeable improvements and I'm sure I could steel line and maybe put bitumen sheets over the top of the steel??? It is something I will have a think about doing. No harm in trying.

 

[hifikrazy]

Similar to the argument that speaker manufacturers would use audiophile cables internally if they make a difference... Wouldn't the speaker manufacturer have done it themselves if adding damping material and bitumen sheets make their product sound better?

 

[Vladimir]

I have removed all the foam wadding from inside my speakers and I should in the near future be lining the inside of the cabinets with steel plate. Also going to rewire with some modern, thicker wire.

Have you considered also bitumen sheets? They are quite effective and easy to work with.

I hadn't to be honest. I know the steel lining mod has been applied to the same speakers as mine before with noticeable improvements and I'm sure I could steel line and maybe put bitumen sheets over the top of the steel??? It is something I will have a think about doing. No harm in trying.

The steel is practically bracing the cabinet and it isn't a dampening material, it also resonates. Try some bitumen sheets directly first, easy and not expensive. If you still want to go further, go with steel and then put bitumen over that.

For test purposes I would use duck tape and not glue the bitumen or the steel diirectly. Once you find the best combo to your ears, then you can commit to glueing permanently.

The foam you removed from the speaker helps reducing standing waves and I would leave it in, at least some of it.

 

[james_LR90]

To be honest I think they sound much better with all the foam removed. They sounded slightly dull with it in and sound more lively without it.

 

[Esra]

looks like fun guys,pls go on with more

people would be suprised if they look into their speakers and meanwhile debate about esoteric speaker cables :roll:

But hey my cheapo Yamaha speakers have all monster cableing in them,I was pretty amazed ...

 

[hifikrazy]

Talking about what's inside speakers, my friend was rather disappointed to see this is what his PMC Fact 8 looks like on the inside. Somehow I expected more from a GBP6000 speaker.

Especially when GBP6000 can also buy you this...

 

[jiggyjoe]

This site is great for learning about speakers: http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm

 

[Vladimir]

I finally added the stinger. Now I've effectively turned a back ported speaker into front via tapering transmission line. Simple, effective, ugly. :shifty:



Surely you can see the similarity between the B&W Scorpio and B&W Nautilus here. The resemblance is uncanny (ish).

 

[Burto]

Made a pair of DIY ribbon super tweeters a few months ago. Fairly easy and I may have been lucky but they sound very good.

Hardest part was finding the cross overs and modification of computer speaker boxes to accept them.

Idea came from Dali ikon (have Zensor 3 ) and must say the ribbons do add sparkle to the highs.

I do like the scorpio tweek idea with the port will try it with drinking straws (the bendy type angled up at 45 degrees)