Very High Quality DIY speakers anywhere? - Page 8

Jeff,

I used both the egg-crate foam and fiberfill in the sub-enclosure.

I only used the egg-crate foam in the outer woofer enclosure and left the one side I attached the crossovers to uncovered as per the plans.

I think sealing the sub-enclosure will make a big difference. So will getting it off the floor. Most of your treble is way below ear level. (unless you too are laying on the floor) Glad to see your speaker coming along.

I just came in from outside. I cut most of the pieces for the front stands. I'll probably glue the columns tonight and then attach the tops and bottoms tomorrow. Stay tuned for pictures.

Joe L.

Thanks JL,
That's the same way I assembled mine.
Jeff

Had the opportunity to cut some more MDF this past weekend. While I was primarily interesting in cutting the pieces I need for the Audax HT Rear speakers, I took advantage of the nice weather to make a few additional cuts for the pieces needed for speaker stands to hold my front right and left channel speakers.

I wanted stands that will compliment the speakers. I found several web-pages showing what others had done for their DIY speakers and my wife and I decided on a design. (She rejected far more than she liked) The design is similar in some ways to the one I referred Jeff to in an earlier message.

First, the base is made of two 3/4 inch pieces of MDF glued together to make a 1 1/2 inch thickness.

As Norm Abram says, "you can never have enough clamps"


The column is a simple tube made of MDF. Here I have already removed most of the clamps (to use them on the base... I guess I do not have enough clamps... yet)


A bit of work with my belt sander and the edges look pretty decent. I also used the 1/2 inch roundover bit on my router to round over the front edges of the column and the top edges of the base. My wife thinks that I should veneer the columns to match the speakers... I'm considering it. Originally, I was going to simply use flat black lacquer. The veneer would really make the stands look like they belong to the speakers...


The stands are about 27 inches tall. This positions the tweeter on the front speakers at 40 inches from the floor; almost exactly at ear level when we are seated. It is also only about 6 inches below the center line of my screen.


Tonight I'll glue up the other stand. If I'm lucky, I'll get another chance to work outside later in the week to sand and round over its edges. In the meantime, I can start assembly of the rear speakers and think about how I want to finish the stands.

Joe L.

JL,
Those stands appear to be very similar to the one's that I saw here in GA. You've done an excellent job.

FYI, I finally got the center channel veneered last night. It was my first venture into veneering and I ruined a 4x2 section because I didn't pay attention to the way the grain ran and when I tried to bend it over the rounded edges, it cracked:-( I was in a hurry and trying to pay attention to my wife and kids all at the same time. Then, there was the problem of removing what was already applied to the cabinet. It was after 1am this morning when I finished. I'll go back to working on the front speakers now. Looks like I'll have to buy another sheet of veneer.
The results are here:
http://lotuseuropa0.tripod.com/audax_center001.htm
Jeff

JL,
I have another question: My center and two fronts came with two pounds of fiberfill. The instructions for the center say lightly compressed fill in the sub-enclosure but nothing about the fronts. How much did you add to each cabinet?
Thanks,
Jeff

Jeff,

I put a handful of fiberfill at the top and bottom of the front speakers (lightly compressed) because I was concerned thet the longer internal dimension might enforce more standing waves within the cabinet. (remember, I made the enclosures about 4 inches longer and 2 inches less deep) It seemed to help.

The Audax plans do not specify any fiberfill in the front speakers at all. If anything, you could try both with and without and see which you prefer. I guess it depends on the efficiency of the acoustic foam in absorbing the backwave from the speakers.

It might warrant a call to madisound... they might have some advice.

Joe L.

O.K., I am trying to remember what the Vance Dickason book said about ported boxes, but I if I remember correctly, it said that minimal fill should be used in ported boxes. Acoustic foam is fine, as long as it doesn't impede the air flow, but fiberfill is normally not reccomended.

Anyone else read Vance's book? Does this sound right?

Thanks guys,
I sent an email to Madisound. Since these are ported, it makes sense that excessive fill could/would impede air flow. I just thought it strange that the center and two fronts included 1-lb of fiberfill each (1-lb for the center and 1-lb for the fronts). The center makes sense because it calls for lightly compressed fill in the sub-enclosure that houses the midrange and tweeter. It probably only comes in 1-lb bags but why did the fronts come with foam padding and fiberfill? There is absolutely no mention of using the fiberfill anywhere. Maybe someone from Madisound will get back to me.
Jeff

Jeff,

I'll bet you I didn't even use 1/2 of a bag so far for all three speakers. (center, left & right)

I doubt you could stuff 1 lb of fiberfill in the sub-enclosure on the center and consider it "lighty compressed" It was probably less than 1/4 lb.

I'll be interested in the response you get from madisound.

Joe L.

I think the reason that the center channel requires some polyfill is that the sub enclosure for the mid and tweet is sealed. It's only the woofer cabinet in the center that's ported.

At least that's my interpretation.

You guys are all making me jealous as you get to hear your wonderful creations right away. Where as I have to wait another 26 days until my house is done!

later,

Don

Guys,
I got a quick response from Madisound...another reason to buy from them. Here it is: "Thank you for your email. When using the 2" foam, no additional fill is necessary"

jeff

Fellow speaker builders, I just weighed my Audax center channel and it came in at 47 pounds! I think that JL's will weigh even more since he doubled the rear panel thickness. I'm looking at the "Sound & Vision" 2003
Buyer's Guide. There are 119 pages of speakers listed. I'm quickly flipping through the pages and I haven't found a center channel yet that weighs this much. This just goes to show that these diy speakers are better built...that is if weight has anything to do with quality.

FYI, my entire Energy Take 5+1 weighs 45 pounds. I did find a couple of center channel speakers that weighed in over 40 pounds and they start at $1,400.
Jeff

Jeff,

I checked with my 20 year old bathroom scale (not too sure of its accuracy), and the center channel weighed about 48 lbs. Left and right speakers weigh about 42 Lbs each.

Have you gotten a chance to do any more listening to your new center channel now that it is fully glued and veneered? I'm curious of your thoughts. I did not have a good center channel before I built the Audax Center, that made the improvement in sound quality far more dramatic. It should be easier for you to comment on how it compares to a commercial center channel.

I am really happy with how my speakers are sounding. My wife even more so. Where in the past, she occasionally would ask that I enable the subtitles in order to better follow the dialog, she made comment that the new DIY Audax HT speakers make it so much easier to hear dialog in the presence of other background sounds in the movies that she has not had any need to ask me to enable the subtitles.

It has been said that our DIY speakers would easily compare to those selling for 3 or 4 times our DIY expense. Clearly, at least comparing speakers by weight, that seems to be true.

Joe L.

I'll have to spend tomorrow reading this whole post and getting caught up. Its quite a bit of reading! The current center channel I have is an Infinity (something) that I bought several years ago and is WEAK compared to what I'm needing. Since I got a projector and about a 8' screen, the picture isn't matching the sound coming from the center channel if you know what I mean. I need a much more "grand" of a center channel to match the picture a little better. I've definitely noticed a lack of sound from my center channel. So....


I have a desire to build the Audax center channel with some slight modifications depending on some answers I get from you guys.

#1 Modification would be the construction of the enclosure. All internal dimensions, speaker configurations, and porting would remain the same. I saw a sub woofer design sometime ago (can't remember where) that was constructed by use of 3/4" mdf inside + 3/4" sand + 3/4" mdf outside. Let me explain this further. Every side (except the front where speakers mount) was composed of sandwiching 3/4" of regular playground sand between two pieces of 3/4" mdf which would result in each side being 2 1/4" thick. This was done by edging every edge of each mdf side with 3/4" strips and then filling the void with sand and putting the other piece of mdf on top of this securing it with glue and screws. This was done for resonance purposes. I'm not a speaker builder, but the design principle made sense and heck it just sounded like a pretty cool thing to do. Heh! Yes, I know this adds much to the construction process, but I believe it would be worth it and obviously would add to the "weight factor" mentioned above. (yes i know weight isn't everything)

#2 Modification would be replacing the Audax speakers with some higher end speakers of the same cone sizes. This of course would mean changing the crossover design appropriatly. I have NO experience in this at all. Speaker choice nor crossover design. This is the main part where I'm looking for guidance. Is anyone up to the challenge of helping me choose some different speakers and doing a crossover design to reflect this. I don't think the enclosure should have to change any if we're using the same speaker cone sizes, but I could be wrong here. This modification would also mean that its not a true "Audax center channel" anymore. :P

Now for some basic stuff that I just don't know and questions I have...

How exactly are power ratings for speakers compiked? I've noticed that this Audax center channel uses several speakers with varring nominal power ratings. If I have a receiver that is 100W per channel, I would obviously desire a speaker with a max of 100W+ worth of power handling. What is the max of this Audax Center channel? Do you just take the nominal power of each speaker in the system and add them together or what?

Please let me know if anyone wants to help with my design challenges or if you can guide me to a place that can help, that would be great too. I think the addition of the sand to the construction of this center channel would be interesting to see and hear.

Thanks!
Ryan

can the sand, you don't need the over kill with a center, the 2 pcs of3/4 mdf will work fine.add tile inside if anything.
always remember kiss -keep it simple stupid- there are lots of great ideas but you cant always use them for your thing.
go lurk around the madisoud board there are a lot of guys who can help .
you cant just change drivers by size.
great drivers and bad crossover = crap speaker.
have your crossover done by a pro like rick craig at www.selahaudio.com
or another pro.
he did my 3.5 way- from what you mention ask him about using the fast-est design for your center or at least the top end-scan speak tweeter and morel dome mid, they work great together.

I don't think it would be that difficult to fill a void on 4-5 sides of the enclosure with some sand. It would be an interesting project for sure and the story to tell would be even more interesting. I'd also be confident that it would definitely help tame any resonance. Maybe using a mortar mix or concrete mix to fill the void could even be better.

My main thing is that I'm seeing that this design has been proven to out preform many "run of the mill" products until you step up into a $1000+ center channel. THIS is what I'm looking for. I know that I've outgrown my current center channel and I am a diy enthusiast for sure! I don't have this $1000 to spend on a center channel. All I might be able to muster would be half of that and I believe This Audax design would beat anything that I could get for $500.

You say "great drivers and bad crossover = crap speaker." Well I don't know if I even know what great drivers are. With that said...

Can anyone answer a few of the basic questions that I had above? Especially the questions that I have concerning power ratings. Thanks!

Ryan, quick note on using different drivers. If you look for the parameters of the drivers, often noted as T/S but technically called the Theil/Small parameters, these numbers tell everything about the driver and what type of enclosure to use them in as well as sizes. The T/S parameters are based on the electrical/mechanical properties of the drivers and allow the designer to come up with a best guess on how to use the driver (sealed box, ported, bandpass....). That along with the frequency repsonse curve and the waterfall plot tells the whole story about the driver. Beyond that, it takes listening tests to see what you think of the driver.
If you are interested in trying this out, you should probably get Vance Dickason's book, The Loudspeaker Design Cookbook. It goes into all the aspects of designing and building speakers.

Svonhof, thanks for the tip and info. I do already have a Loudspeaker Design book, but not the one that you mention (this one is old).

What is the exact RMS powerhandling of the Audax Center Channel? The speakers are all listed as different W raning around the 50W-60W Range. How is this calculated and what is this Audax Center Channel exactly? I'm concerned because my receiver is a Pioneer Elite VSX45TX and is 100W per channel. If the standard Audax setup will work fine with this receiver, then I may not need to change anything.

Ryan,

The following quote is from this page http://www.audax.com/doit/us_ht02.shtml on the Audax web-site that describes the Audax Home Theater speakers.


I am currently using an amplifier that is 15 watts per channel with the Audax center channel and it is plenty loud enough for movies. No, it will not get so loud that it is uncomfortable to listen to, but way more than enough to immerse myself in the soundtrack.... plenty loud enough to have made me jump when presented with an unexpected loud noise. You do not need 100 watts, but the Audax Center Channel can easily handle it.

You cannot simply add the power handling ratings of the different drivers in the enclosure, because the energy in a movie soundtrack is not evenly distributed between the drivers. Usually, there is far less energy at treble frequencies than at others, therefore, it is OK if the tweeter has less power handling capability.

With all that in mind, your 100 watt per channel receiver would do perfectly.

Joe L.

I'm going to be building the Audax surrounds sometime in the next couple of months. I plan on maybe going to a 6.1 system. Does anyone know if it might be possible to convert the surrounds to a bipole design? Or even a pseudo design? My understanding is that you simply need to wire the speakers out of phase. Of course I'm sure that there is more to it than that. My Theater room is rather small at 10 x 13 x 9. Should I just build the surrounds as they are and have direct radiating speakers in the back and sides? I know Scott (Svonhof) uses that arrangment. I have heard his system and it sound quite impressive.

To be honest I'm not even sure if it would be worth it to go the 6.1 route with the size of my room. But any receiver I get in the next few months will more than likely have that capability anyway.

Ryan,

I think I have the answer to your question. Each speaker is rated at a certain wattage, but the inductors I believe, but may be wrong, split the power sent from the amp up into chunks that each speaker can handle. I have a recevier that puts out 100 watts per channel and my Audax mains handle it fine. The center channel has the same drivers. I know there are different impedence ratings on speakers and that can cause the speaker to draw more power, but that is beyond my knowledge.

As far as the sound goes, I have been to several different retailers that sell many types of speakers and the Audax mains that I built sound as good, if not better, then what I have heard. With the exception of the Martin Logans that I heard at Magnolia Hi-Fi. Of course those didn't sound $6 grand better than my Audax's.

By replicating the Audax design, what price range of speaker do you think they compare to? Before I found this design and searched AVSForums for the design and got lead to this thread, I had been looking at Polk http://www.polkaudio.com/home/products.php?category=5

Can anyone compare this Audax to any of these? Again I ask, with all the effort of building these and after they are completed, what price tag would this center compare to?

I haven't compared them to the speakers you linked to unfortunately. I did however listen to the Klipsch reference speakers quite a bit at the local Good Guys before and after I built the Audax speakers. They sound just as good to my ears. This is saying a lot as I really like the sound of Klipsch speakers and almost bought them before stumbling across some DIY speaker sites. Of course you have to remember that speakers are very dependent upon the room and I haven't done any A/B comparisons aside from comparing it to my Sony center(see below).

I also listenened to some Definitive Technology speakers and the previously mentioned Martin Logans. I didn't listen as intentally as the Klipsch speakers, but the Audax came close to my ears. the Martin's did sound better, but I'm not sure if it was actually sounding better or just a placebo effect as I know they are about a fourth of my annual salary!

You will certainly be able to purchase speakers that sound better than the Audax, but not for any where near the price.

As for the center channel specifically I haven't had a chance to listen to it with my mains as they are in storage right now. However, before I moved I had a rather inexpensive Sony center flanked by the Audax mains. When I switched between Stereo and 5.1, the Audax Mains really brought out the weakness of the Sony. I mean the clarity and warmth these speakers put out is amazing. I really can't wait get into my new house so I can experience how well the center channel integrates into the system.

Don, the debate over 5.1, 6.1 or 7.1 is on-going. My take on it is that if you have a small room, as you will, you will be fine with 5.1. Will you notice a difference between 5.1 and 6.1, possibly.

As far as making the regular surrounds into a bi-pole, you would need different crossovers to handle dual tweeters and then you could leave the midrange on the front panel with the tweeters on the sides. This of course means that you will have side surrounds and the rear center, which means you want to have the side speakers at ear distance from the front wall. If you are sitting against the back wall, that is no good, as the tweeter will fire directly into it.
That is my take on it.

I think my solution is to just build the surrounds as they are and then put my current surrounds as the rear speakers when I upgrade my receiver. If there is a noticeable difference then great. If there isn't, then oh well. Nothing really lost.

I need the new receiver anyway to handle componenent switching. The 6.1 is just extra.

Now I need to just get a height channel decoder. Just kidding!

darthopus,
That is what I'm doing. I have a set of Energy speakers and I'm using them as surrounds and rear speakers. I actually have five Energy Take 5 speakers, an Energy center and an Energy 8" 100w sub. I may try to buy one more Take 5 and have four surrounds and two rear channels. I could also use four of the Take 5s as surrounds and use the old center channel as a rear speaker. My two Audax front channel speakers will be finished by Saturday and my center was done last week. At this time, I don't have any plans to replace the Energy speakers in the rear because they are perfect for that job. I just need to find a use for the old subwoofer because I also recently completed a 250 watt 15" sonosub.
jeff

Hi guys,
I've got another question: The 3" port tubes are supposed to be 5.25" long. the rear panel is .75" thick and the baffle is 1" thick. Does that count as 1.75" of the overall port length? The distance from the front of the baffle to the outside of the rear panel is also 5.25". Both ends of the port are supposed to be rounded. Does that mean that I should use my good carbided tipped router bit on the PVC tube, or can I cut the PVC tube 1" shorter and just round the front of the baffle and the rear panel?
Jeff

Jeff,

I asked exactly the same question on the Parts Express message board when I was building my center channel. It was even more appropriate since I had a thicker rear panel.

The answer was that it is the total length that matters.

The port tube, in my case, would extend less into the enclosure since more of it was within the 1 1/2 inch thick rear panel than in the original plans with a 3/4 inch rear panel. In your case, the rear panel and baffle count as 1.75" of the overall port length.

I did the center different than the L/R speakers. For the center channel, I had a very thick walled cardboard tube that I used for the port. (it came free inside the bolt of fabric I used for my theater)

I cut it flush with the outer wall of the enclosure and used my roundover bit to make the transition. Here is a picture:

If you look real close you can see that I left about a 1/16th inch rabbet on the outermost edge of the port flair. That allowed me to trim the veneer cleanly around the port. If the roundover was flush with the rear panel, I don't think it wiuld have been as easy to make the veneer look as good around the port.

I used PVC tube on the L/R. There, they do not go all the way through the panels, they only go about 1/4 inch into the panel. The roundover is therefore only on the MDF.

I would think you could use the router to round over the PVC as I did with the cardboard tube. Just keep the bit moving as to not melt the PVC.. (that could make a mess)

Joe L.

Thanks Joe,
So at least my current tube is correct. I assumed that it was total length and made it that way. I've got to do something about the PVC edge. I currently have rounded ports but then there is the end of the PVC which makes it look like a rabbeted step. If I could only find some really thin plastic tubing that is 3" ID. I'm ready to play these things and I've still got approx 8' of 3" PVC, so I'll get the router out and try to round the edges.
Thanks again,
Jeff

Has anyone thought of adding the technology to the ports like Polk does with a "cone type thingy" pointing into the port?

Does anyone manufacture devices like this? I've never seen them on parts express. The piece is made of hard plastic and from what I understand, its supposed to smoothe out frequency response and disperse the lows. If no one manufactures this, I guess it would take someone that knows a bit about molding plastics to accomplish such a thing.

Also, another thing concerning port tubes, has anyone thought to use an adjustable port tube? I'll bet this could be taken and modified to adjust from 3" to 7" or so and give some user configuration to this center channel.

Ryan, I think you are obsessed with Polks!
I am not sure what that thing does, except possibly slow down some of the air and also re-direct it so that you can have the speaker close to/or against a wall.