Oh man! THANKS!
First let me explain you. The Yamaha RVX-673 has 2 Subwoofer outputs (RCA).
According to the manual:
NOTE: Its called 0.1, the receiver has 2 outputs.
As you say, a high Q (and Qms) with low Fs response could do the work for what Im looking for, meaning: a good loking, average sized cabinet cheap subwoofer with low freq response (similar to THX subwoofers) for my HT.
As Charlie said in a earlier post about how to reduce the air speed from the vents, I could do a smaller cabinet and compesate with the tunning port/vent. But it will look like a chimney. I dont like that...
Also, in the worst case scenario that I dont like the final result, I just take the subwoofer out of the cabinet and put it in my car! 😛
Oh, by the way, yesterday I bought the JBL GTO1214D!! It was hard to find! The sellers missundertood the models and try to sell me the GTO1214 (4ohm, single coil).
Also I bought Neutrik Speakon connectors, a backplate with Neutrik Speakon connectors, Speaker connectors (+ and -) and plug.
TPR Cable for the Speakon connectors.
More clamps, rubber hammer, rope, and many other stuff!
If everything goes well I will be buying a 3 months used power amp next week.
It's cheap but it has very good specs and recommendations from some sound engineers that I know here.
The specs:
2 X 350w @ 4 Ω
2 X 240w @ 8 Ω
700w @ Bridge.
• Selectable crossover function per channel with high cut at 80hz
• Forced cooling.
• Balanced XLR and unbalanced TS inputs.
• Speakon outputs per channel plus one independant output on Bridge mode.
• Two levels (gain) controllers, Power switch, LED power indicator, 3 LEDs per channel to indicate pressence of signal, saturation and drop .
• Shortcircuit, power-on/off peaks/"punches" and radio interference protections .
Ill be expecting your comments!
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Hey guys! I've been playing around and testing new configurations to make the box.
Also used different output power: 240w, because that's the max of the amp (at 8ohms).
Changed the diameter of the vents to a more exact measure according to pvc plastic tubes.
Here are te results.
Dou you think that this is more adecuate and smoother response?
Thanks for all the help and comments!
Also used different output power: 240w, because that's the max of the amp (at 8ohms).
Changed the diameter of the vents to a more exact measure according to pvc plastic tubes.
Here are te results.
Dou you think that this is more adecuate and smoother response?
Thanks for all the help and comments!
280L is way too big.
Drop it to ~120L. That should flatten the 20Hz peak.
You could also use one amplifier channel for each voice coil, and connect the inputs together. This would give you a few dBs extra headroom.
Chris
Drop it to ~120L. That should flatten the 20Hz peak.
You could also use one amplifier channel for each voice coil, and connect the inputs together. This would give you a few dBs extra headroom.
Chris
Did it. Here are the results.
Also changed the tunning to 21hz, so it could be around 20hz at -3db.
It was very hard (or impossible) to get a flat response at 120hz. So I did my best to keep the that "ripple" over the 120hz.
BUT! theres a little problem...
As you see, port speed is over 26, but it's when input power is 250w...
I would never ever use it over 150w, so I thing it's ok.
What do you think?
Hi ofesad,
Looks like you are putting a lot of work into this project, have you measured the actual T/S parameters for the JBL GTO1214D, and what are the parameters you are using?
Regards,
Looks like you are putting a lot of work into this project, have you measured the actual T/S parameters for the JBL GTO1214D, and what are the parameters you are using?
Regards,
I'm informed (when I was looking to do something similar to this - its been put on the back-burner for now) that these drivers hold very closely to the specs given by JBL.
IMO, the room is likely to present more of an issue than T/S being out by 10%.
Your graphs look good, but I agree that the airspeed has gone too high. Could you use two smaller ports to get the tuning and airspeed correct?
You realise that the frequency scale is logarithmic, right?
It goes 10-100-1000Hz, so the line you're looking at is two up from 100Hz, making it 300Hz.
IMO, the room is likely to present more of an issue than T/S being out by 10%.
Your graphs look good, but I agree that the airspeed has gone too high. Could you use two smaller ports to get the tuning and airspeed correct?
You realise that the frequency scale is logarithmic, right?
It goes 10-100-1000Hz, so the line you're looking at is two up from 100Hz, making it 300Hz.
... 
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Hi Oliver,
Agree,Your simulation should be a good sub using the JBL driver even with the coils connected in series.
Submitting a few sims concerning post#1 that I held back after reading the subsequent ones... but here they are:
b🙂
Attachments
I am. You may say Im a perfeccionist, but also, when I do something with "my own hands", I try to match every single spec and requirement possible to have the best results and enhance the versatility of the final product.
Also, in what sound concerns, Im very very VERY demanding and picky. Every time I have a new set of speakers (or something related to sound), I take my time to test the best EQ, sometimes it takes a few hours, others a week or months of testing. Also the position, trying different positions even for a inch.
Maybe that's why my friends always praise the way my stereos and speakers sound. Hehe!
All that said, that's why Im on this new proyect of DIY... finally, after many years I can afford an AV Receiver.
Sadly I cant measure the T/S. I have been reading about how to do it, and it's kindda easy.
But... my piece of silicon multimeter doesn't measure Hz/Freq 😡
So... a few moments ago, I just ordered over 100u$s of electronics goods and DIY parts from certain chinese website, including a new multimeter:
The others stuff:
A mini power amp (3W per channel) working with 5v.
Other power amp @ 15w per channel at 9v
A lot of Banana plugs (Red and Black), Alligator clips and cables for testing
"Goot" Desoldering Wick Remover
Solved. I didnt realize of the scale...
tb46 and Bjorno, I cant thank you enough for running those simulations! I really appreciate your inputs on the subjet!
Guys, I think you know about this, but still I tell you... In the JBL website (USA), you can buy a refurbished GTO1514 Double coil for 99u$s. Free shipping.
Just saying, if someone is looking for something good and cheap to experiment.
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If you have not already do browse through this site:
Collo's DIY Subwoofer Enclosures
Lots of useful info to take into consideration.
Collo's DIY Subwoofer Enclosures
Lots of useful info to take into consideration.
Anyone following jazzcyclists questions can now find them here,
http://www.diyaudio.com/forums/subwoofers/231583-subwoofer-cabinet-advice.html
Guys! Just came the mail with the customs confirmation for my Yamaha RX-V673 receiver.
On Monday will go and check it out.
So, plans for this weekend:
Clean the room, take out all the innecesary stuff and furniture, paint the walls, cut the closet metal frame, finish the new tv furniture/stand and many other things!
Now Im going to begin so I will be updating any news! On the subwoofer subjet, I think that tomorrow will go and get the MDF.
If any has any suggestion or comment, please let me know before I start making cuts on the MDF!
On Monday will go and check it out.
So, plans for this weekend:
Clean the room, take out all the innecesary stuff and furniture, paint the walls, cut the closet metal frame, finish the new tv furniture/stand and many other things!
Now Im going to begin so I will be updating any news! On the subwoofer subjet, I think that tomorrow will go and get the MDF.
If any has any suggestion or comment, please let me know before I start making cuts on the MDF!
As been a long long time since I updated this post, so I wanna show you guys how it's going.
Let me tell you, the first time I used my receiver (Yamaha RVX673) I was totally shocked with the sound quality. It was like the sound was "cleaning" my ears.
Now Im buying more speakers trying to reach 9.2 channels.
Today I received my JBL ES25C (Center Speaker). The upgrade was incredible. I coudn't believe that the sound improvement could be so huge. Around 35 - 40% better an clearer.
Here is a video so you can see how it's taking shape.
Baticovacha 3.1 - YouTube
On the other hand, I had some problems with the subwoofer. Im thinking that maybe 8omhs wasn't a very good idea. Maybe I should change it for a 4ohm because it needs very much power from the amplifier so you can feel it (kicking/punching).
Still, when it does sound, the room rumbles all over
The adjustments I had to make to improve the sub: more filling, cut down the pipes/airvents form 73cm to 68cm.
But Im still having problems locating it, cause even in the corner, the low freqs sounds better behind the couch and standing on the oposite corner of the room.
Ill be expecting some comments and advices about it!
Thank you all for the help!
Let me tell you, the first time I used my receiver (Yamaha RVX673) I was totally shocked with the sound quality. It was like the sound was "cleaning" my ears.
Now Im buying more speakers trying to reach 9.2 channels.
Today I received my JBL ES25C (Center Speaker). The upgrade was incredible. I coudn't believe that the sound improvement could be so huge. Around 35 - 40% better an clearer.
Here is a video so you can see how it's taking shape.
Baticovacha 3.1 - YouTube
On the other hand, I had some problems with the subwoofer. Im thinking that maybe 8omhs wasn't a very good idea. Maybe I should change it for a 4ohm because it needs very much power from the amplifier so you can feel it (kicking/punching).
Still, when it does sound, the room rumbles all over
The adjustments I had to make to improve the sub: more filling, cut down the pipes/airvents form 73cm to 68cm.
But Im still having problems locating it, cause even in the corner, the low freqs sounds better behind the couch and standing on the oposite corner of the room.
Ill be expecting some comments and advices about it!
Thank you all for the help!
Hi ofesad,
Sounds like you build a nice subwoofer, you shouldn't be able to locate it. 🙂
Have you tried the method of placing the subwoofer in you normal listening position, and moving (crawling) around the room until you find the point where it sounds best, then placing the subwoofer there, and listening in your normal listening position?
Regards,
Sounds like you build a nice subwoofer, you shouldn't be able to locate it. 🙂
Have you tried the method of placing the subwoofer in you normal listening position, and moving (crawling) around the room until you find the point where it sounds best, then placing the subwoofer there, and listening in your normal listening position?
Regards,
I would bet $1000 that changing to 4 ohms would gain you at most 1 decibel more volume on peaks. Or maybe LESS peak volume. The amp you have looks like it would run much hotter at 4 ohms too.
It's not clear to me why you are unhappy with the sub-just volume? Car subs generally have a high moving mass, to get a low resonance in small boxes. This means they are power hungry!
So your amp is fine, way more power than commercial subwoofers.
I wonder though if you have some cancellation going on. What happens if you switch the polarity (phase)? What are your crossover settings? How about time delays? Actually, you should play a mono source and play 2 channels only at a time to be sure all the polarities are correct: L vs R, L vs C, R vs C, Lfront vs Lrear etc etc. Google "polarity test track"
And forgive if I missed it, but if you are running the sub as LFE you are missing a lot of the bass-are your main speakers set to "small"?
It's not clear to me why you are unhappy with the sub-just volume? Car subs generally have a high moving mass, to get a low resonance in small boxes. This means they are power hungry!
So your amp is fine, way more power than commercial subwoofers.
I wonder though if you have some cancellation going on. What happens if you switch the polarity (phase)? What are your crossover settings? How about time delays? Actually, you should play a mono source and play 2 channels only at a time to be sure all the polarities are correct: L vs R, L vs C, R vs C, Lfront vs Lrear etc etc. Google "polarity test track"
And forgive if I missed it, but if you are running the sub as LFE you are missing a lot of the bass-are your main speakers set to "small"?
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