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xtrmaniac

Diy Subwoofer

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Thank you JSS! These examples will bringing me closer to decide what I should build.

 

Definitely going with Infinity drivers in 2 folded horns will be the most economical choice, however I was looking also into the TC Sounds Epic, Dayton Reference HF, Dayton Ultimax and FI SSD 12" and I simulated them in the WinISD. Please find enclosed the screenshot taken from the project where I uploaded 6 different 12" drivers.

2 Ultimax drivers it will give me around 6 cubic feet in a sealed enclosure and for my requirements it will not work. Great driver though. Also Dayton Reference HO seems to have good values in WinISD.

The only problem is that it's hard to decide which driver I should choose based on values, volume and reviews and a good advice will be most welcomed regarding this.

 

You are right about popalock's videos show. I didn't intend to have them in the same category, I was just amazed about that and I know that I could even get closer to something similar. I've read that actually there 16 of SI 18" which is a lot of displacement.

 

Thanks a lot! I will place the corner traps on the front corners.

 

All the best,

 

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Thank you for the answers in the thread. They helped me a lot and I really appreciate your feedback. I will keep the thread updated when I will start building the subwoofers and with the new results but for now I will go off-topic just for the following problem.

 

In the meantime the high frequency on Surrounds was improved. I adjusted the crossover from the AVR (at 100Hz), distance position, I used a decibel meter and some other details and now is playing very smoothly, the sound travel clear and clean. Ratatouille, Oblivion and Act of Valor can tell a story now :)

After taking the latest distance measurements, the center is situated at 8ft from the center listening position. The Towers are at 9ft and the right surround at 11ft and the left one is at 10ft. The distance between the wall and the speaker is around 1ft or less.

The room treatment is not yet finished. I plan to add acoustic panels behind each Tower and 2 acoustic panels behind the sofa, however after seeing the latest graphs which are attached, perhaps I should reconsider the number of acoustic panels.

 

In the file attached, on the first pages the measurements are from Anthem software (red - measured / black - target / blue - calculated) after all the details were worked out and the rest of the measurements are done by REW.

 

I've used the mic from the Anthem (ARC-1 Anthem) which I used it in REW as it is, without calibration. The .cal file present in the AVR software didn't work and I don't have the specifications of the mic for now.

The connections were made using the USB port for the mic and the laptop HDMI output connecting the AVR. The tutorial suggested that I should use a -12dB level on the signal generator but it was too loud and it was reaching the sound distortion. Then I change it to -16dB. Instead of 75dB on SPL meter I was using 72dB with -20dBRef. This gave me something between 2-4dB HeadRoom. All the graphs were taken only on the listening position mentioned above with the mic in omni position.

 

My curiosity paid off since the high freq were quite good compared with Anthem graphs, at least on the surrounds but I saw 2 cancellations at 4kHz and 12kHz. The left Tower is shifted with 1kHz to the right.

I played some focal wave sounds at 3k, 4k, 5k, 10k, 12.5k, 16k and I didn't hear if there were something wrong there. The voice frequency sounds great when I'm watching movies or listening to music.

 

That makes me think the mic has a problem but used in the Anthem software which have a calibration file, the mic seemed to be fine, or there is something wrong with the room and I need to hurry with the room acoustic treatment or I missed something when I was setting up the REW or is just a glitch. I repeated 2 times the measurements with the same result. What is your opinion about this?

Definitely I need to have accurate graphs using a calibrated mic as UMIK-1 and to change the mic positions for more details, but it raised some questions and I don't know if I should be worried or not.

Compared with the results from the ARC Anthem I shouldn't.

 

Also, based on the impulse graph, could you please tell me if I should add acoustic panels behind the surround speakers?

 

These are the settings used for REW. Please let me know if I should change them.

2 Sweeps

-16dB FS level (should I change the value?)

-20dBRef - I have got around 72dB on SPL meter

2-4dB Headroom - should I use more headroom?

 

All the best,

 

PS: I have read about the xls sheet in the Low Content Thread. I still need to compare the new values from the forum with the old ones from the excel file in order to adjust it. I should share it as it is or I should wait? I incline to wait until everything is settled. Please let me know your feedback.

Frequency Response_resize.pdf

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What does the mic look like? It could be a cancellation from the mic body that it accounted for in the cal file.....as the dips appear ubiquitous.

 

JSS

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Good morning,

 

This is the mic used by Anthem.

 

The storage that I have for this thread is drastically reduced and I cannot attached more files but the link below should tell more about the mic used.

 

www.anthemav.com/downloads/ARC-1_PDS.pdf

 

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I would bet it is the mic, as save for the L channel, 4k and 12k appear to be the null points. On the Anthem screens, your surrounds still have some HF roll off, but it is much improved. Acoustic treatment will help the peaks/dips from 100-500Hz the most, esp front/rear wall and ceiling. In my opinion, it is difficult to outfit a room with too much absorption.

 

There are two schools of thought on 'tons of absorption':

 

1. Use as much as possible to 'eliminate' as much of the room as you can, or 'listening to the recording AS IT WAS RECORDED, IN THE ROOM IT WAS RECORDED IN'.

 

2. Use only enough to rid yourself of harmful cancellations, or 'listen to the recording as played back live WITHIN YOUR ROOM'.

 

Some people prefer a livelier room, I do not. If I am listening to a recording of a symphony in a concert hall, a 'live' room will contribute it's own signature on top of the hall's signature it was recorded in.....it's a matter of preference. Lots of folks on this forum want to hear what is on a disc, no additions or enhancements. I fall into this group. Not everyone does, and I understand why. Toole does a great job explaining it in his book. I have 30 2-4" thick OC703 traps in my room (most are 4"), all but 4 are 2'x4'. I left the side walls just prior to and behind the side surrounds untreated for some early reflections from my surround speakers....but when I move up to 7.1, the surrounds will have their ceiling reflection treated/baffled as well.

 

JSS

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Good morning Gentlemen,

 

It's been a busy year and it's been a while since I updated this topic. First of all I will like to Thank you JSS and nube that they gave me so very generously of their time, knowledge, and patience to understand what I need to build a new pair of subwoofers and to enclose them in a room which was treated.

 

Even if the thread began with a statement, I discovered that there are only a handful of drivers that could comply with a 3 cubic feet enclosure and to be on a budget.

This year Christmas came a little earlier than anticipated and now I am the happy buyer of 4 x TC Sounds Epic 12" drivers.

 

I have some details about what I have in mind for building the subs and everybody's feedback is welcomed.

- 4 x TC sounds Epic 12" drivers in dual opposed cabinets design with inside measurements of 23 x 16 x 16 ~ 3.41 cubic feet from MDF,

- 1 x Behringer EP4000 amplifier which I intend to connect the subs in bridge mode

- 1 x miniDSP 2x4 + plugin + UMIK-1 mic setup with REW software and Linkwitz Transform for fine tuning

- The drivers will have 2 + 2 ohms dual voice-coil in series connected, then the drivers will be connected in parallel in the same cabinet and the last thing the subs will be connected in series to the amplifier to have 4 ohms at the bridge mode - correct me if I'm wrong

- 1 lb acoustic poly fill in each cabinet

- 2" standoff from the floor and a 1/2" beveled glass top plate installed at 2" above the driver - This is my conclusion, please let me know if I should review the measurements

- Looking as black mirror finish furniture

 

It seems that this is becoming more like a habit to build speakers during winter however I'm very excited to start and hopefully I will finish them in a timely manner.

 

I will update as soon as I will have new details.

 

All the best,

Daniel

 

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That sounds good...how do they model in that size enclosure?  Also, instead of bridging, you can connect the coils in series on each driver and both drivers in each box in parallel and just use each channel on the EP4k separately at 2 Ohm.

 

Any progress on the room treatment front?

 

JSS

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Based on your suggestions I made the room treatment by adding 6 acoustic panels - 2 behind the mains, 2 on the back of the sofa and 2 on the ceiling. The improvement is huge, it's infinite better than before.

I intend to use and buy corner traps later on due to the aesthetic look, hopefully before connecting the subs however for 100$ each this will wait for a while.

 

I have attached how the drivers model in this size enclosure. The simulation was done with 2 drivers adjusting the enclosure size and had the parameters taken from TC sounds website were their specifications were made for dual voice-coil wired in parallel.

 

Because the specifications are only for voice-coil wired in parallel I should consider to have them connected like this and both drivers from each cabinet should be connected in series? Thank you for your advise, I will connect them separately into the amp.

 

Daniel

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Parts Express notes that the specs are tested with coils in series.  I think there is a typo on the TC site.  

 

Room treatment is paid only lip service by so many, but once you actually do it, the results speak for themselves.  I have been asked by many friends and co-workers to recommend speakers, and the first think I ask them is "what is the room like".  When I start mentioning acoustic treatment, they go into a kind of stupor, and only come out of it when I say 'the speaker I would recommend is'....I usually get told that acoustic treatment is out of the question.  I usually then say that both a $300 and a $3,000 speaker will likely sound equally awful, and they may as well buy the speakers with their eyes, not their ears, like most folks do.  Before I say that, I'll talk about directivity, and I usually get the 'I can't have speakers that large' comment, then I'll mention line arrays, and I get the 'they are too expensive to buy, and I don't have the time to build them' line.  I'll then ask what they really want out of the sound system, and most cannot say, and some just say 'it has to kick ass'.  I then recommend they visit the nearest car audio custom shop and literally ask for that.  They will hook you up.  Most end up buying sound bars and/or HTIB or Bose, 'cuz it sounded badass at Sam's Club'.....oh well.

 

/rant

 

JSS

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Parts Express notes that the specs are tested with coils in series.  I think there is a typo on the TC site.  

 

Room treatment is paid only lip service by so many, but once you actually do it, the results speak for themselves.  I have been asked by many friends and co-workers to recommend speakers, and the first think I ask them is "what is the room like".  When I start mentioning acoustic treatment, they go into a kind of stupor, and only come out of it when I say 'the speaker I would recommend is'....I usually get told that acoustic treatment is out of the question.  I usually then say that both a $300 and a $3,000 speaker will likely sound equally awful, and they may as well buy the speakers with their eyes, not their ears, like most folks do.  Before I say that, I'll talk about directivity, and I usually get the 'I can't have speakers that large' comment, then I'll mention line arrays, and I get the 'they are too expensive to buy, and I don't have the time to build them' line.  I'll then ask what they really want out of the sound system, and most cannot say, and some just say 'it has to kick ass'.  I then recommend they visit the nearest car audio custom shop and literally ask for that.  They will hook you up.  Most end up buying sound bars and/or HTIB or Bose, 'cuz it sounded badass at Sam's Club'.....oh well.

 

/rant

 

JSS

haha :D

 

As the saying goes, you can lead a horse to water but you can't make it drink!

 

It is frustrating when people just don't take the time to understand or make best use of their money - it's such a waste!

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