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Good point Mike. I've been busy lately and haven't really sat down to enjoy a movie in a long time. I think tonight I'll fire up the sub and the Buttkickers and pop in that Dungeon Siege movie with Jason Statham. I'm not expecting much, but hopefully it will have some good bass content at least and I can content myself for a while longer.

End complaint and minor threadjack.
 
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I am extremely impressed with the subwoofers that have been built in this thread. I want to build
(handbrake permitting- thats the wife) a pair of these Mach 5 Audio IXL-18.4's. For my HT.

Your design looks great and I am sure you have put a great deal of work into the design etc: Is there a site or a copy of the design schematics of these speakers so I can build them to your exact specifications??

Any advice would be appreciated.

Regards

ROB
 

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Discussion Starter #27
Thanks for the compliment. The only plans I made were the cabinet size drawn on a piece of paper. The bracing was figured out as I went along. The cabinet dimensions are 38" wide x 23" deep x 30" tall. I don't remember the bracing sizes or their exact placements, but if you do get the "go ahead" to build, I'll gladly pull a driver to access the inside and get you the required measurements.
 
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Thanks for the compliment. The only plans I made were the cabinet size drawn on a piece of paper. The bracing was figured out as I went along. The cabinet dimensions are 38" wide x 23" deep x 30" tall. I don't remember the bracing sizes or their exact placements, but if you do get the "go ahead" to build, I'll gladly pull a driver to access the inside and get you the required measurements.
Thanks for the offer Mike, it is appreciated!! You have convinced me to make the purchase. I feel like living dangerously, so I will buy them first then tell the good wife second!! When I am in a position to do the enclosures I will get back to you to obtain the required measurements!!

BTW, in a previous post you advised "I downloaded some frequency sweep tests and it's very obvious there are a couple of peaks. I"ll have to get some measurements done to see where the problems are".

Have you acheived this yet, and if so what did you need to do to rectify the apparent problems??

Your advice is appreciated!!


Another convertee to Mach 5 Audio!!

Cheers ROB
 

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Discussion Starter #29
I never got around to doing measurements even though I bought a BFD, downloaded REW and purchased a proper sound card. Too much going on with a daughter having twins, work, and home life. But I'll get there yet! The peaks are room modes that the BFD will handle, I'm pretty sure of that! :T
 
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Thanks Mike, please excuse my ignorance, but being relatively new to this caper I do not know what the following means "The peaks are room modes that the BFD will handle" Can you please explain. Sorry to be an annoyance!
 

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Discussion Starter #31
Sorry to be an annoyance
No such a thing. We all have to learn sometime! Here's a simplified explanation. If you play test tones from 80 hz down to 20 hz, and they are all the same loudness, a graph would show a straight line. This would be called a flat frequency response. If at certain frequencies, say 25hz, it is 6 db louder, then a graph would show a peak at 25 hz. You would use the BFD to apply a filter at 25 hz to cut the peak. In the real world there is no straight line in the graph due to the way sound waves interact with a room, it has peaks and valleys and you use the BFD to smooth out the frequency response as much as possible. To see how subs measure in the room, head over to the REW forum and snoop around. Lots of posts there showing the in room response graph, and then the graph with the BFD smoothing it out as much as it can.
 
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Thanks Mike, that helps a heap. This is an area that I am very interested in so hopefully I will pick things up as time goes on!!!

Cheers, ROB
 
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Mike, thanks for the heads up re: the Mach 5's, the order has been made!!

I am however in a bit of a dilemma. I am extremely impressed with your design but having made a template of the size the enclosure, it is quite large, this is not necessarily a problem as my speakers are quite large, they are a copy of Duntech Sovereigns.

BUT, would a Sonotube be possibly a better option?? What gives better bass in your opinion?? I am an ignoramus in relation to this area of expertise. With the Mach 5 18" IXL's if I were to consider a sonotube what would be the minimum sonotube size I would be able to get away with?? I have had a look at the software but I am afraid that it is all rocket science to me and in my early stages I do not have the confidence to do the calcs.

I must admit, I like the idea of a sonotube as well, but a couple of people I have showed them to have laughed at me and told me they are too big and take up too much space. Maybe your Subwoofer design is the best design after all, but prior to committing I thought I would ask the question!! As an aside, If the sonotube was too large, would I be better off changing the 18" drivers to a smaller driver which would result in a smaller sonotube or Subwoofer enclosure. The only thing I am concerned about is if I go to a smaller driver I will be sacrificing quality of bass because I am of the opinion a bigger driver surface with a well matched enclosure and port will give a lower more resonant bass.

Please do not spend too much time on this question as I do not want to be a pain in the backside. I am certainly enjoying browsing on this forum and am learning more all the time. Have a good one. Cheers ROB
 

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Discussion Starter #34
The box size can be made smaller. 8 cubic feet tuned to 18 hz with a 6 inch diameter port 25 inches long would work. The box would be 30% smaller and you would give up 3db of output in the 16hz to 18hz range. As for sonotube size, a 22 inch diameter tube would allow enough room to mount the sub and have enough room for the base plate legs. A 22 inch diameter tube would be 4' 1" overall to have a net volume of 8 cubic feet. It would have to be 5' 5" overall to have a net volume of 12 cubic feet. Obviously, the larger diameter the tube is the shorter it will be. You'll need to see what size would work best for you along with what is available in your area.
 
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Mike, thanks so much for your assistance, your knowledge is invaluable!! I suppose I can just wait until the drivers turn up and worry about exactly what I will do design wise later. Will the size of the room be overly important??

The dimensions of the room are 35ft X 18ft. It is not entirely square, but these figures give a very accurate idea as to the size.

Is going to a sealed box to reduce size going to sacrifice sound, I presume it will as porting etc: will allow a deeper more resonant bass??

Once again thankyou for your time, it is greatly appreciated!!! Regards ROB
 
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Mike, my Mach 5 18"s drivers have turned up and I am stoked, they look brilliant!!

I find it impressive that a driver at that price can come in cast baskets as opposed to pressed tin. I have shown some people at work your design and they are suitably impressed. The only concern anyone has given is their size. Is that a standard size piano in your room, or is it an undersize piano??

I have told them you have advised me that I can go for a design 30% smaller, and I have been told "do that, they will not look so imposing" These people are thinking more so of asthetics as opposed to performance though. If I did go smaller 3db, although a sacrifice, would not be too much of a sacrifice I suppose. What are your thoughts?? I think the room is big enough to take the larger boxes??

If I were to make the decision to go 30% smaller would I just make the box 30% smaller than the dimensions you have already given me?? Oh, decisions decisions.......
 

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Discussion Starter #38
I'm not sure what a standard size piano measures, but mine is 56 inches wide. My subs may look imposing because they are both against the piano. My room is 15' x 26', but there is a hallway on the right side of the right hand sub. The hallway is 4 feet wide, leaving 11 feet for both subs and the piano to fit. Your room is 18ft X 35ft. You're going to want to get all the output you can get in a room that size. I personally wouldn't go any smaller than 12 cu. ft. tuned to 16 hz. The subs will not look imposing in a room that big.

Box or tube. Be aware a sonotube sub will be alot cheaper to build. For a port you would use a 6" or 8" smaller sonotube. The flared ports with the extra extensions and the elbows in my build were around $200. For that price alone you should be able to buy most of the building materials required for a sonotube sub. Just a heads up.
 
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Decision has been made due to your advice!! 12 cubic ft subs they are!!! I presume I get MDF sheets cut to the exact size you advised, "The cabinet dimensions are 38" wide x 23" deep x 30" tall" BTW, do these dimensions include the depth of the MDF, and how thick was the sheeting you used??

Once cut, (I will get the MDF supplier to cut them to size) I can commence construction.

BTW, where do I locate the necessary pipe and flares to construct the Ports??

When you get the time (no rush as I have approx 8 weeks until I move into the house) it would be appreciated If as per your previous comment: "I don't remember the bracing sizes or their exact placements, but if you do get the "go ahead" to build, I'll gladly pull a driver to access the inside and get you the required measurements." if I could obtain these measurements for the bracing.

I promise when they are completed that your name will be famous with my neighbours. When I receive their complaints I will quote your name and say you are the designer of the magnificent beasts that are rocking the foundations of their house!!

Once again, thankyou so much for your help, your advice has been invaluable and extremely informative!! Cheers ROB
 

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Discussion Starter #40
The cabinet dimensions are external measurements, the MDF I used was 3/4 inch material. Draw the cabinet on a piece of paper and mark the appropriate dimensions, it makes it easier to visualize.

You need to KNOW that the MDF supplier will make accurate cuts. You can't have pieces that are 1/8th or 1/4 of an inch out. Any piece that is either to big or too small will throw everything off and nothing will fit properly. Accuracy is important!

I'm not sure where to get the required flared ports in Oz. Contact Sam at Affordable Drivers, he may be able to help you.
 
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