My DIY Stereo Speakers

[HiFiManish]

Hi All,

I have been following Hifivision and DIY forum for quite some time. Here had wanted to share my DIY journey till now, which I could make with inspiration drawn from other FMs' work and valuable suggestions posted here. I just completed 2 speaker sets which I am using as stereo speakers. These are too big to be called bookshelf speakers and sounding good to my taste! It is consisting of 10 inch Bolton full range and 4 inch Dainty tweeters in 45 L box. It took me more than 8 - 9 months to reach at current stage.

• My Bolton speakers (4 Ohms) - almost 18 years old :-D - were lying idle for most of the time and passed through test of time and nature in form of intense heat, moisture and even flood in my hometown.
• Boxes (48 L) + Tweeters (8 Ohms) from S P Raod Bangalore - Got from S P Road Bangalore.

My journey has gone through following milestones, spending about 2 - 3 months at each milestones, while reaching 4:

1. Bolton + Philips 3 inch tweeters in cabinet
2. Bolton + Dainty 4 inch + cabinet padding with egg crate like material which is used in fruit packing as layer (in pic 1) - This improved sound to some extent.
3. Bolton + Dainty 4 inch + cabinet padding with egg crate like material + egg crate in 1 of the box! - Not much enhancement in sound quality from step 2 though.
4. I further tried to play around with some resistors to create equal impedance for both speakers, however result was not something great as Bolton's voice got muffled in tonality. So I did not put it in. Putting resistor in parallel to tweeter obviously would had been redundant and power wasting.

Some pics of milestone 3 are attached below. I recently got a chance to listen to Sonodyne floor-standers @ Croma. And to my ears, my setup is sounding only a bit lower than that...! - Giving me much of confidence!

At this point requesting suggestions from all DIY Gurus on what further enhancements (economical) can be done.
I am aware of following:

1. Crossover network - Will it be required for full-range?
2. Putting in 4 Ohms tweeter - I previously had put in Philips tweeter, however current setup is better sounding.
3. Applying Glass-wool / Poly-wool in boxes - please suggest how much SQ will it improve from current state of cabinets, as I have already put egg-crate material?
4. Current boxes are made of MDF + Ply. One option can be of going for pure MDF or wood cabinets which will cost much more (in tune of 5K per cabinet as I understand) - however with current speakers does it make sense to spend so much?
5. If at all opting for custom make of boxes then getting them designed in such a way that axis of both speakers fall in same plane - Does not look possible for me :-D

Please let me know your views...!

Thanks for reading my first post on HiFiVision!

Regards,
Manish.

 

[Hari655]

Good Work..!!

These days i see DIY is very active cool! keep it up.

But i am sure you will not stop here...hyeah:

 

[prosenjit]

great work man..great work

 

[HiFiManish]

Thanks Hari & Prosenjit for encouraging words...! :-D

Next step I am contemplating is to look in to crossover part...! From whatever I have read, I have some queries and I would request all folks to help on following:

1. Is it advisable to put crossover when using full range speakers?
2. As I have read, getting TS parameters would be the first step to go for crossover network - does anyone have TS parameters for Bolton Full Range drivers?
Again intent of this question is inherent from known difference b/w woofer & full range! This is the reason I am not looking for ready made crossovers which mostly have points for tweeter/(mid range)/woofer - (Otherwise for a novice like me any circuit called crossover could had worked...!). Please let me know if crossovers would be available for this scenario too...with my search I could not get anything specific!
3. If I have to measure it, then it will need software (freeware) for the same. Can I get the desired testing done from my laptop - which is not having sound card and has only 3.5 mm stereo output socket...?

I am starting to read through crossover litrature, so some of above queries may be due to ignorance, so please let them go..!

Thanks,
Manish.

 

[trittya]

Nice effort there.
AFAIK, Bolton did not publish TSPs publicly.
As regards X-overs, do yourself a favour, opt for active 2/3/4 way. You won't regret it.

 

[omishra]

One simple mod - you can try dual side self adhesive foam tape 2"-3" wide. That white colored tape pasted inside complete surface and over than paste some packing bubble sheet. Bubbles facing inward and plain surface over tape.
This tape damps the resonance of panel and bubble sheet absorbs internal reflections to major extent. You can sprinkle resin adhesive (e.g. fevibond) & little polyfill material (1/4" layer) over that.

 

[HiFiManish]

Thanks Trittya & Mishra Sir...!
Hunt for bubble wrap starts now...!

 

[quad]

Manish, good going.
That egg crate material - is it the cardboard type?
It should be foam which has the same shape. Pl see other speaker threads
here for suitable materials.

 

[omishra]

One simple mod - you can try dual side self adhesive foam tape 2"-3" wide. That white colored tape pasted inside complete surface and over than paste some packing bubble sheet. Bubbles facing inward and plain surface over tape.
This tape damps the resonance of panel and bubble sheet absorbs internal reflections to major extent. You can sprinkle resin adhesive (e.g. fevibond) & little polyfill material (1/4" layer) over that.

Btw above suggestion is only for plain MDF surface and not over egg crate.

 

[keith_correa]

Bubbles facing inward and plain surface over tape.

Didn't understand this. If the flat surface of the bubble wrap is stuck on the tape, shouldn't this be "bubbles facing outwards"? Or have I understood this wrong?

You can sprinkle resin adhesive (e.g. fevibond) & little polyfill material (1/4" layer) over that.

What would be the role of the layer of polyfill here?

 

[HiFiManish]

Manish, good going.
That egg crate material - is it the cardboard type?
It should be foam which has the same shape. Pl see other speaker threads
here for suitable materials.

Thanks Quad for pointing it out!
Looks like I define the words 'Novice' or 'Amature'.
I checked other posts and got that what egg crare foam is!
Anyways... Would request all of you to please guide me to shop in Bangalore, where I can get it. Fron net I am getting B2B contacts only. Though I'll look at some mattress shops today also.

I should get bubble wrap in coming week, which I'll change in one box to start with.

Regards,

 

[omishra]

Didn't understand this. If the flat surface of the bubble wrap is stuck on the tape, shouldn't this be "bubbles facing outwards"? Or have I understood this wrong?


What would be the role of the layer of polyfill here?

Bubble wrap has bubbles at one side, that surface needs to be free in inside air. Mean other surface stick to tape.

Polyfill sprinkled to control bass response inside, without that also not a problem because here driver parameters are unknown. So just double sided foam tape and bubble wrap work fine.

 

[HiFiManish]

Hi All,
today I m planning to do overhaul...!
Had a query to mishra sir and all experts:
1. I have got bubble wrap and polywool mterial of about 0.75 inch thickness. I am pla.ning to put In double layer on it over bubble wrap. With this material can I reduce or completely remove the self adbesive tape part? Actualy the area to be covered would be around 15 sq. Feet, hence tape requirement would be huge!
2. If I am putting tape only for sticking wrap on mdf purpose (
ay be 2 to 3 strips only on each surface) and not from covering the surface point of view - how much effective would it be in resonance damping purpose.
Regards.

 

[HiFiManish]

Dear All,

Just finished the refurbishing. Attached are some pics.

I could not get economical double sided tape, instead I used a layer of thick cloth stick over the entire surface - to dampen vibrations.
Next layer is of bubble wrap. After that a 2" thick layer of polycoat (which I got, which searching for egg crate foam, which I could never get).

Sound is improved now. Vibrations are reduced, though not to a great extent, I feel it is also related to actual material of box which in not MDF at all sides.

Anyways...I am enjoying the sound!

Thanks to everyone for valuable suggestions!

Regards,
Manish.

 

[smd]

Egg basket idea was truly ingenius... keep it up buddy.

 

[ketansethi1987]

I think poly fill layer would have been enough.

I tried cotton and it improved the sound quality to great extent. Very good sound absorbing and damping material. Reduced box echo to a great extent. Will try poly fill now

 

[j_jaga]

Hi,

I have been following this forum and in specific the DIY section as I plan to do my stereo speakers on own.
I have used the Bolton full range 5" speakers in the past and they sound good for the money.
Would like visit and to hear how your setup sounds.

Thanks

 

[Audioden]

As per my experience goes it is not worth to spend time and effort on items that are meant for shopkeepers /people who know not much about audio.

To be frank bolton dainty are good for places like shop where among noise some speakers will do.

Just because the items are cheap dont go for it.As the core elements are (hardboard like cabinet,boltons)compromised there wont be little richness of the music ,
No offense ,some day so called "improvements " will not weigh 20% of a decent dIY speakers i have been in that path ,trust me!

try for good drivers like peerless,vifa,even dayton reference via import or indian sources (i am sure peerless is available here )
Incase of import yes the 2 midbass will be 8-12k(no escape!)
get silkdome pairs via ali express/via shop and ship in2k

Still 12K is a decent budget for a quality build.

 

[HiFiManish]

@j_jaga: You are welcome. We can plan sometime in APR or so!

@Audioden: Thanks for sharing your views & experience. It is definitely a good guidance for quality audio setup!

Mine setup is more of using available resources in most economical way. This helped me learn some of the basics for sure! However to my ears this setup also sounds decent, compared with little audition I had of branded setup.
Next I am planning to upgrade - to start with better cabinet as now I can differentiate b/w acoustics of current cabinet material and better quality materials. Time depends on my patience, free time and budget..!!!

Regards,

 

[omishra]

Mine setup is more of using available resources in most economical way. This helped me learn some of the basics for sure! However to my ears this setup also sounds decent, compared with little audition I had of branded setup.
Next I am planning to upgrade - to start with better cabinet as now I can differentiate b/w acoustics of current cabinet material and better quality materials. Time depends on my patience, free time and budget..!!!

Fully agree, I was using diy bookshelf speakers made using Bolton drivers. Just by trial and error, I could get it to decent level. Though limitation arise but after you have everything else in place. Whatever speakers you use, other components also required to put that quality into it.