Replacing sound proofing in cabniets

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I bought some acoustic fill from them. They have a few selections including eggcrate foam, stuffing, and dampening sheets.

As Barry aka "Bright Star Audio" mentioned, i typically do not advocate stuffing the port in any way, shape or form. That is, unless one is "experimenting" and does so in a fashion that is easily reversed.

Having said that, most mass produced and even many "audiophle approved" and "hand built" vented designs will benefit from what i've mentioned. As mentioned in another thread, i just got done doing this to a pair of speakers that currently retail for over $3K. The results were quite obvious and highly beneficial. For the record, these speakers were HIGHLY under-designed to begin with in almost every aspect. Even though they were poorly designed, lacked proper implimentation of the design, which resulted in them sounding like crap, they get rave reviews all the time. Sean
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Sean, I take it that you are referring to the Legacys you have been working on?

As you know, I am not such a big fan of their speakers. I will say that the Focus and the minimonitor sound the best in the lineup to my ears. Legacy is my biggest disappointment in audio, where the whole definitely does not add up to the sum of its parts. Of couse, I am speaking "on paper", and your recent exercise probably proves that the sum of the parts isn't all that much to begin with.

When I was about 19, I finally had enough money to buy a pair of Legacys, and a used pair popped up in a nearby audio salon. After receiving their catalogs for years, I just "knew" they were the best speaker out there. Especially, at the price point.

I mean, come on, all those woofers are drivers, in a big, beautifully finished, well braced box. The testimonials were jammed with people who had moved to them from all of the respected brands - Thiel, Wilson, Mirage - let's just say that from this and all of the other "wonder products" I have encountered, I have zero faith in testimonials these days.

Fortunately, or unfortunately, I decided to go to the store to listen to my Legacies. It was a foregone conclusion that I would be buying them. The audition was simply a formality. Credit card in hand(if they were at a distant dealer, I would have just had them shipped), I drove on over.

Wow! All I can say is that there is no other product that I have encountered in audio that failed to live up to its hype like these babies. The overwhelming feeling I got was that it was impossible for a speaker this big and bold to come across this small and weak.

I won't go into all of the other details, but in a Legacy show, at the Allen Organ Company, which seems to have bought the line from Bill Duddleston, along with his services, I got the same exact impression.

The VERY valuable lesson I came away with was to NEVER DRINK FROM THE LABEL and NEVER TRUST THE MAGAZINES OVER A REAL, PERSONAL AUDITION!

There are formula's for the very thing your wanting to do.

The best investment you could make, would be to purchase the 'The Loudspeaker Design Cookbook'.

If you line the walls of the speakers with a dampening product, that will cut down on externally transmitted cabinet vibes. But, if the speakers was designed with that taken into account, then leave it alone.

I'm surprised, but I shouldn't be,that no one here has mentioned the difference in lining the walls and using a fill of some sort in the cabinet, will have two very different out comes.

Filling the cabinet with some sort of fiber fill, depending on the amount used, will change the QTS of the speaker. Changing it dramatically is possible. The more fill used, the larger a cabinet the driver sees, thus changing the sound.

The more fill used, the higher the QTS will be. The higher the QTS, the boomier the speaker will sound, most of the time. There are a million variables, but this is the
general rule.

Whatever the cost is of the book now, it was $30 when I purchased it several years ago, will be your greatest investment. It's writen in a way that most people can understand the concepts. Not rocket science.

Good luck.

Trelja: Yes Joe, these were the Legacy's we were working on. We just got them finished tonight and are pretty happy with them. That is, considering what we started off with. They are like a completely different speaker now i.e. MUCH better sounding. They still have a "ported" sound to them, but you can't get rid of that without sealing them or using a more advanced bass alignment. This type of problem is especially hard to conceal when the designer crams TWO woofers into a box that is too small for just one of the woofers!!! All of these designs use a box that is just too darn small for the drivers being used, hence the bloated bass that lacks definition. Believe me, this is only a very small part of the problem too. I took pictures of the crossover network before and after. If i can figure out how to transfer these pics from my camera to my puter, i'll forward them over. As i mentioned in what was probably another thread, we were able to go from a total of 122 connections in the pair of crossovers down to 46 connections total!!! All of this by paying attention to how the crossover was laid out on the board. There were NO circuit changes made, so it's not like we changed the parts count in order to reduce the number of connections. Then again, i'm "preachin' to the choir" on this one, so i'll save it for a more appropriate time : )

Steveallen: Most vented designs can be drastically improved by adding damping materials internally. Very few vented designs make use of optimally sized boxes, so adding internal volume via damping material typically helps to reduce the output peak at resonance and smooth the overall response. This is because internal reflections are damped and the box appears to become "bigger", bringing the alignment closer to what the driver would optimally like to see. To top it off, this approach will typically produce increased clarity and definition due to the reduction of the aforementioned internal standing waves being reproduce and less leakage from the ports.

While i do agree with your suggestion to read this book, many people have read hundreds of books and even graduated from schools with a degree. Reading textbooks and passing tests vs knowing how to properly interpret and apply that information are two very different things. This is why we have so many speakers that sound like crap but look so good on paper. Even those that know how to talk the talk end up not knowing how to walk the walk due to a lack of understanding and experience. If this were not true, Trelja and i wouldn't have initially been impressed with what we read and saw about Legacy's, but we were. Wanting to believe and being able to believe are two different things, especially if you are honest with yourself. Sean
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