Replacement drivers

[K7W]

I am restoring a pair of Energy Reference Connoisseur 22's, the ones made in Canada, purchased in 1986. One of them is blown and I would like to find modern drivers that will work well in the cabinets. The tweeter is silk dome and the cabinet was built around a single 8" poly driver and cabinet is rear ported. Original sound was great but the efficiency was only about 85dB so they needed more power to really make them dynamic. I need a place to start. Are any of you familiar with this speaker design?

 

[TLS Guy]

I am restoring a pair of Energy Reference Connoisseur 22's, the ones made in Canada, purchased in 1986. One of them is blown and I would like to find modern drivers that will work well in the cabinets. The tweeter is silk dome and the cabinet was built around a single 8" poly driver and cabinet is rear ported. Original sound was great but the efficiency was only about 85dB so they needed more power to really make them dynamic. I need a place to start. Are any of you familiar with this speaker design?

We get these questions again and again. You can not generally reverse engineer a speaker. It is far easier to design and build a speaker from scratch.

All speaker drivers have unique Thiel/Small parameters, and unique acoustic responses. So all speakers require unique enclosures and unique custom crossovers. In addition great care has to be taken to select drivers that can actually work well together. You can not randomly pick drivers.

Unfortunately when a speaker blows a driver, that is almost always the end of the road for that speaker, unless an exact replacement driver can be found for that speaker.

If you do want to embark on the course of action you describe, then you have to start by measuring the T/S parameters of each driver from the working one. This is a large set of numbers and finding another driver that is even remotely close to the replacement you require hardly ever happens. You will never find drivers with the same acoustic response either, so, even if you can find the bass driver that will work in the box, you must design the crossover from scratch using the T/S parameter and measured acoustic responses.

All that means to say it is far easier to design and build a speaker from scratch than do what you are attempting. In addition you would have to redo the working speaker with the same drivers and crossovers. Both speakers must be identical.

 

[K7W]

We get these questions again and again. You can not generally reverse engineer a speaker. It is far easier to design and build a speaker from scratch.

All speaker drivers have unique Thiel/Small parameters, and unique acoustic responses. So all speakers require unique enclosures and unique custom crossovers. In addition great care has to be taken to select drivers that can actually work well together. You can not randomly pick drivers.

Unfortunately when a speaker blows a driver, that is almost always the end of the road for that speaker, unless an exact replacement driver can be found for that speaker.

If you do want to embark on the course of action you describe, then you have to start by measuring the T/S parameters of each driver from the working one. This is a large set of numbers and finding another driver that is even remotely close to the replacement you require hardly ever happens. You will never find drivers with the same acoustic response either, so, even if you can find the bass driver that will work in the box, you must design the crossover from scratch using the T/S parameter and measured acoustic responses.

All that means to say it is far easier to design and build a speaker from scratch than do what you are attempting. In addition you would have to redo the working speaker with the same drivers and crossovers. Both speakers must be identical.

Thanks for the hard truth, you have my respect.

 

[K7W]

I have questions regarding cabinet design... Does the cabinet's effects on the dampening of a driver affect the loading on the amplifier or just what you hear?

 

[TLS Guy]

I have questions regarding cabinet design... Does the cabinet's effects on the dampening of a driver affect the loading on the amplifier or just what you hear?

The answer is both. The T/S parameters define the electro/magnetic properties of the driver and its physical properties. Speakers can be loaded by the spring of air in a sealed box, or more often loaded to augment the LF output and tune it properly so the bass is tight. This is Q. The box tuning has a dramatic effect on the impedance curve. Speakers can be in Helmholtz resonators, pipes or horns. The common loading is the B4 box which is a tuned Helmholtz resonator. The size of the box, diameter and length of the port is unique to every driver. The dimensions are highly critical. In this system there is a saddle type of impedance curve with the low point of the saddle at the tuning frequency, and the peaks either side. This also effects the relationship of phase between voltage and current known as the phase angles.

A sealed enclosure on the other hand has one peak of impedance. Depending on the T/S parameters some are suited to sealed, or vented designs, and some require horn enclosures. Pipes are a special case where drivers have also be selected with care..

Once you get the hang of it all and especially now, with computer modelling for box and crossover design, it is not that difficult. However there is a learning curve and a didactic body of knowledge required. However there are plenty of DIY designers and builders like myself who can successfully build and design good speakers. In addition to computer modelling, we now have good measuring tools within economic reach of the DIY designer/builder. I have been at it for over 60 years now. I first did a computer assisted design in 1984. These speakers are still giving excellent service in my AV room as the surround speakers. I have never had a commercial speaker in any of my systems. It was much more work when you had to do all the math calculations long hand!

 

[K7W]

Thanks for the explanation. I am realizing the amount of work that goes into a good speaker system. I am a designer by trade but my body of knowledge of speakers is very small. (I wish I could start my career over.) Is there a good teaching source for calculating a system design based on off-the-shelf drivers(if specs are provided) for crossovers and enclosure geometry. I am a product designer with a EET education so I feel i could learn it and I am willing to experiment and fail, just don't want an epic fail. Maybe I'm asking too much.
Thank again sharing your knowledge.

 

[Gmoney]

Thanks for the explanation. I am realizing the amount of work that goes into a good speaker system. I am a designer by trade but my body of knowledge of speakers is very small. (I wish I could start my career over.) Is there a good teaching source for calculating a system design based on off-the-shelf drivers(if specs are provided) for crossovers and enclosure geometry. I am a product designer with a EET education so I feel i could learn it and I am willing to experiment and fail, just don't want an epic fail. Maybe I'm asking too much.
Thank again sharing your knowledge.

Ummm... hope you ate a good Breakfast or packed a Sandwich? No, Quote :Maybe I'm asking too much: Maybe you bit off more than you can chew?

 

[TLS Guy]

Thanks for the explanation. I am realizing the amount of work that goes into a good speaker system. I am a designer by trade but my body of knowledge of speakers is very small. (I wish I could start my career over.) Is there a good teaching source for calculating a system design based on off-the-shelf drivers(if specs are provided) for crossovers and enclosure geometry. I am a product designer with a EET education so I feel i could learn it and I am willing to experiment and fail, just don't want an epic fail. Maybe I'm asking too much.
Thank again sharing your knowledge.

Here are a couple of good places to start.

Loudspeaker Design Cookbook: Vance Dickason: 9781882580477: Amazon.com: Books

Loudspeaker Design Cookbook [Vance Dickason] on Amazon.com. *FREE* shipping on qualifying offers. Loudspeaker Design Cookbook

www.amazon.com

Speaker Building 201: Ray Alden: 9781882580453: Amazon.com: Books

Speaker Building 201 [Ray Alden] on Amazon.com. *FREE* shipping on qualifying offers. Speaker Building 201

www.amazon.com

I guess my most important advice is that after you familiarize yourself to have an understanding of the terms, and understand the physics at least in basic form. You must not be afraid to get stuck in and begin. The physics of speakers design is actually not that complicated but can appear so at a cursory glance. I would say the part that takes most experience is crossover design. However those are easily modified to your heart's content. Just make sure you have it accessible. Crossovers often need a few iterations before you can be happy. However between your ears and measurements you will get it right. To me you sound just like the sort of guy who should become a DIY builder. The reason to be a DIY builder is NOT to save money for cheaper speakers. It is all about better speakers. Speaker building is a unique blend of science, craft, experience and intuition. That is totally against the philosophy and ethic of the large corporation and the fundamental reason we are swamped with speakers that are not very good.

 

[K7W]

Thanks so much! This is more information than anyone has been willing to offer. I enjoy building and good sound and mental stimulation. Nothing worth doing is cheap! Amen to "better speakers".

 

[K7W]

Ummm... hope you ate a good Breakfast or packed a Sandwich? No, Quote :Maybe I'm asking too much: Maybe you bit off more than you can chew?

Maybe....willing to try...there is always something to be learned.

 

[Gmoney]

Maybe....willing to try...there is always something to be learned.

Was picking bro.

 

[TLS Guy]

Thanks so much! This is more information than anyone has been willing to offer. I enjoy building and good sound and mental stimulation. Nothing worth doing is cheap! Amen to "better speakers".

Keep posting here!