Speaker Cone - How to Build One w/ Cardstock

Using an old 4 Ohm loudspeaker to demonstrate my method and procedure to construct a new (loudspeaker) speaker cone (truncated cone/frustum) when a matching replacement cone is not available.
Online resources:
A pattern for a truncated cone - Math Central
Check out the Excel Spreadsheet by Don Nevin.
mathcentral.uregina.ca/qq/data...
Cone/Frustum/Truncated cone Calculator
r = r
s = rH
Angle = 360 - A
www.hampsonlife.com/conecalcul...
And another great resource where no math or drawing template is required.
www.templatemaker.nl/en/cone/
Black Cardstock Paper | Solid-Core Cardstock Paper | Flat Shipping
www.cardstock-warehouse.com/p...
Above cardstock also available at Amazon.
Speaker Polarity Tester w/ AD8302 Phase Detector Module
• Speaker Polarity Teste...
Music attributes:
The 126ers
Thanks for watching and subscribing to my channel on vintage radio repair and other related circuits.
#restoreoldradios

[@OIE82]

Thank you Mr. Don. I am about to have to dive into re-coning a 4" PM speaker off of a Truetone radio. Without your video tutorial I would not even have attempted it. Especially the cone template part. Thanks for all your great videos. Luther

[@RestoreOldRadios]

Luther - glad it has been helpful. I hope all goes well on your rebuild. Best, Don

[@ndrmkhn6559]

Thank you Sir for this detailed description of the cone replacement process and old good days math. With your craftsmanship and relaxing voice it was a pleasure to watch.

[@RestoreOldRadios]

Thank you for your kind words and I’m glad you enjoyed the content. All the best. Don

[@maxblade01]

That's a great repair Don, I learned a lot and with that calming voiceover I kinda feel relaxed too. I am in my 30's and like to listen to music and repair/ restore my own stuff and restoring and modding speakers is one of my favourite things to do. With love, Max 🙂

[@RestoreOldRadios]

Max - I appreciate your kind words and I hope your repairs/restorations go as planned. Thanks again and all the best. Don

[@hestheMaster]

Well done Don. This is one the most difficult repairs to do on a radio. Takes a finess for sure and several tries to find the sweet spot to fit the cone properly. The before and after was a great difference, and proof it needed to be done.

[@RestoreOldRadios]

Thanks Steve. It was a perfect donor for a little experimentation. Take care and all the best. Don

[@johnblystone8781]

The before and after sound quality improvement was significant. Thanks Don for spending the time to show the detailed procedure. Beautiful job.

[@RestoreOldRadios]

Thank you John. I was surprised with the improvement; definitely noticeable to my old ears. Best, Don

[@jims2222]

This is an excellent demonstration of your process to replace a speaker cone. You’ve made an intimidating task look much easier. Thank you.

[@jdmccorful]

Ditto!!! Enjoyed watching.

[@RestoreOldRadios]

Thank you Jim. It was a fun project and I still have much to learn about the subject. Thanks again. Best, Don

[@RestoreOldRadios]

Much appreciated John. Best, Don

[@batalladelaspiedrascaballe2966]

Excellent job and explanation !! Congratulations !!!

[@RestoreOldRadios]

Thank you, much appreciated. Best, Don

[@gurmangrewal0046]

This guy is really good to explained this theory

[@RestoreOldRadios]

I appreciate you watching and reaching out. All the best. Don

[@LarryDeSilva64]

I use that Renaissance wax on my rifles and gun stocks always makes them look great. Now I have another use for it. Great tear down and build up video of that speaker Don. You really do great work Don.

[@RestoreOldRadios]

Larry - me too. It’s a great rust inhibitor and works well on those old radio chassis’ too. Thanks for your kind words Larry. Best, Don

[@rjlinnovations1516]

Excellent repair. Sending my support

[@RestoreOldRadios]

Much appreciated! Best, Don

[@jimdukarich1692]

I really like the Excel spreadsheet and math to create a cone from a flat sheet of paper.

[@RestoreOldRadios]

Jim - I agree; it's a well laid out spreadsheet and so easy to use. Thanks for watching and I hope you're doing well. Best, Don

[@hds0405]

Absolutely fantastic tutorial and resource references, thank you!!

[@RestoreOldRadios]

You're very welcome! Glad you found it helpful. All the best. Don

[@jimgross5]

Definitely saved to my list for the tutorial I will follow. Thanks so much.

[@RestoreOldRadios]

Hope it helps Jim. I’m sure the process can be improved upon and I would appreciate any feedback as you tackle your upcoming projects. Best, Don

[@deanschmeltzer9620]

Excellent ! There is no other word ! Thank You Don!

[@RestoreOldRadios]

Dean - thank you. Keep me posted on your efforts and feel free to reach out if you have any questions. Best, Don

[@lanebrewer6168]

Excellent! Great job. This is just what I’m looking for. Your channel is one of my favorites!

[@RestoreOldRadios]

Lane - thank you, I appreciate your kind words. Thanks again for watching and reaching out. All the best. Don

[@carloszambrano3227]

Excellent work, salute from Venezuela.

[@RestoreOldRadios]

Thank you so much. I appreciate you watching and reaching out. Best, Don

[@mohitrahaman]

Thanks for the video and the links, great knowledge resource. I now wonder how the GSM of the paper will affect the tonality.

[@RestoreOldRadios]

Good question! For these old radios from the 30s and 40s you can’t hear any differences, but I’m sure a modern day high fidelity system would make things more noticeable to a trained ear. Best, Don

[@mohitrahaman]

@@RestoreOldRadios Thanks Don. In the context of guitar cabinet speakers I do think cone thickness will definitely impart voicing to different speakers, I will look for more info about speaker doping, and definitely start by trying out your method with various thickness of cardstock.

[@RestoreOldRadios]

@@mohitrahaman Sounds great. Please keep me updated on your results/findings. Best, Don

[@DERB_Seymour_Indiana]

Very impressive Don. At some point I have to bite the bullet and attempt something similar. I have several old Zenith AM-FM tube radios of the same type, all of which have bad or no speakers. I doubt very much my attempts will be nearly as elegant as yours. :)

[@RestoreOldRadios]

Thank you Doug. Don’t underestimate your abilities; I know you’re more than capable to mirror or exceed my results. Have fun and go for it. Best, Don

[@tectalabyss]

Great job Don. L and s all my very best.

[@RestoreOldRadios]

Thanks for watching Bobby. Best, Don

[@fibberscloset498]

Very nice, Don. Thank you.

[@RestoreOldRadios]

Thank you Martin. All the best, Don

[@CraigHollabaugh]

This was very interesting and informative. Curious, why did you glue the voice coil first then the surround? Does this lead to better alignment? Thanks from Colorado.

[@RestoreOldRadios]

Great question. Being the homemade cone is not perfectly symmetrical, I didn’t apply adhesive at the same time, ie., around the voice coil and surround area to ensure I didn’t have any rubbing of the voice coil. I probably could have done both at the same time and got good results as well, which is the common practice. Sorry for my belated response. Best, Don

[@CraigHollabaugh]

@@RestoreOldRadios thanks for the response, no worries on time delay.

[@Veritas1980-Chill]

This is very helpful, thank you. I have a set of pioneer cs-g101waii speakers that I am trying to repair.

[@RestoreOldRadios]

Glad it helped. I’m getting ready to build a new cone myself for a little 5” electrodynamic speaker from 1941. Hope you’re successful. Best, Don

[@kwacz]

Nice video. I have 2 speakers one has a good cone but the spider came unglued from the voice coil former, however i also noticed that if i gently push down it pops into place until i play it. Even when popped in place, the spider and cone are up a little farther than normal and there is barely any resistance when pushing down on the cone and is extremely easy to bottom out. Much easier than any other speaker I have. Is this fixable? also where do i get the round flat felt pieces for the old school felt dust caps as when I do my recone this is also shot and will need to be replaced.

[@tbk19656]

What a awesome video. Pretoria, South Africa. Will you able to share the excel spread sheet.

[@RestoreOldRadios]

Thanks for watching. A link to the spreadsheet is in the video description along with other… All the best. Don

[@t1d100]

Excellent work.

[@RestoreOldRadios]

Much appreciated. Thanks for reaching out. Best, Don

[@chuck0mx]

Just perfect ... Nice solution ...

[@RestoreOldRadios]

Much appreciated Valdir. Best, Don

[@FahadAli-nr8im]

Well done 👍✅ Good job Sir 👌👌 its very Helpful for making new one❣️Love From Pakistan 😘

[@RestoreOldRadios]

Thank you. I’m glad it was helpful. Best, Don

[@hugojaviersilveyra9817]

Excelente muchas gracias 😊

[@RestoreOldRadios]

Thank you. I appreciate your input. All the best. Don

[@westelaudio943]

The rattling is gone, that's good. But so is all the treble - because of the missing whizzer cone and the much greater inertia (mms/cms) of the new cone/suspension structure. This technique is useful for an A.M. radio, but I wouldn't do it on anything seriously reproducing music - better just to put in a modern day full range speaker driver then - you can still find such resembling the original one.

[@RestoreOldRadios]

Yep, I agree; it’s perfect for those old AM radios. Thanks for reaching out and watching. Best, Don

[@lunam7249]

whizzers and even full range 4" speakers can sound very good

[@westelaudio943]

@@lunam7249 Sure, but this is more of a mid-woofer than a full range - it can only reproduce lower frequencies well.

[@RohitKumar-zi8sv]

Good bro 😎

[@RestoreOldRadios]

Thank you. Best, Don

[@domeseri1110]

Great job. Can the foam surrounds be purchased ?

[@RestoreOldRadios]

Check out my earlier reply. Best, Don

[@hungpham-uy6ks]

thank you sir i really like your videos its help me alot but i cant find the way how to observe the informations in the website :(( hope you help me❤❤ but its okay if you dont😊😊

[@RestoreOldRadios]

Did you check the video description? I placed the information in that area. Best, Don