which amp produces teh test tone i assume it teh denon AVR.
if it is the AVR then how come you can hear the test tone and not the signal. i think the gain of teh diy amp should be ok.
what source are you using. DVD? CD? try FM. FM comes direct from the AVR.
does teh AVR have 5 channel Matrix.?
if it is the AVR then how come you can hear the test tone and not the signal. i think the gain of teh diy amp should be ok.
what source are you using. DVD? CD? try FM. FM comes direct from the AVR.
does teh AVR have 5 channel Matrix.?
hey i gotta ask this...i am sorry if i sound rough....
in some AVRs there is a menu (usually viewed via a video input on the TV) that allows you to turn on or off the sub output. have you checked this? again i am sorry to ask this but often we miss out something simple. we are after all human.
BTW this thread is very hot ...i just realised we have crossed 200 posts.
in some AVRs there is a menu (usually viewed via a video input on the TV) that allows you to turn on or off the sub output. have you checked this? again i am sorry to ask this but often we miss out something simple. we are after all human.
BTW this thread is very hot ...i just realised we have crossed 200 posts.
You are not being rough but here is the checklist
1. the sub output is on.
2. I have tried DVD and tuner in both 5 channel stereo and Dolby Pro-Logic II mode and it has 5 channel matrix.
3. The test tone is from the denon.
4. I have raised the output level of the sub pre-output.
But what about the active low pass filter before the amp stage. Do receivers have a LPF inbuilt or is the sub-out just a pre-amp tap. If there is no LPF in the denon, then I have to pass the signal through an LPF, right?
BTW, there is a loud hum when I connect the sub out to the amp. But the sound is absolutely good when I connect my cheap diy fm radio to the same amp. I am beginning to feel my denon has a problem, perhaps a grounding one.
I have tried using a coil in series with the woofer and without also. But no luck. Any ideas?
1. the sub output is on.
2. I have tried DVD and tuner in both 5 channel stereo and Dolby Pro-Logic II mode and it has 5 channel matrix.
3. The test tone is from the denon.
4. I have raised the output level of the sub pre-output.
But what about the active low pass filter before the amp stage. Do receivers have a LPF inbuilt or is the sub-out just a pre-amp tap. If there is no LPF in the denon, then I have to pass the signal through an LPF, right?
BTW, there is a loud hum when I connect the sub out to the amp. But the sound is absolutely good when I connect my cheap diy fm radio to the same amp. I am beginning to feel my denon has a problem, perhaps a grounding one.
I have tried using a coil in series with the woofer and without also. But no luck. Any ideas?
Problem solving...mhh...
there is no fun if everyting starts working first shot...isnt it...! 😀
A few silly questions from me...!!
1) At what frequency is the test tone?
2) What kind of an amp is your DIY amp.?
Could u please check what frequency does the HPF formed by the input/feedback network of ur amp cutoff?.
(Normally there will be a 6db/oct HPF fromed by one of ur input resistors and ur coupling capacitors.
Common error, wrong value of capacitance. If the capcitance is too low ur Low Frequencies will be affected.
Also Please check that ur AMP output does NOT have any DC componets in it.
3) Does the AMP hum when its input is kept floating and the Volume control is set to MAX.?
4) Test 1. Reduce the volume on your sub amp. Try touching the active input alone.
Does that produce any hum.. ( be very careful with this experiment and perform it at low volume, bare foot and only
on solid state AMP's)
Does this produce a hum.? Try increasing the volume till about half till u hear a hum.!
If the PSRR of ur amp is high there are less chances that u'll hear a loud hum.
5)Try connecting this amp/speaker input to one of the unused Line level outputs. Does that make any sound.
6) If there is a hum try touching the ground/sheild of the RCA(still connected to the AVR), standing barefoot.Does that take away the hum.If yes there is a grounding/shielding problem.
7) Also check if u have not accidentally inverted the polarity of ur input cord.
Is it true that u dont hear any sound at all when u have connected ur AMP to the subwoofer output on the AVR.
Does ur normal sub produce enough volume. Check what is the inpit signal level specified in its manual.
Check the input sensitivity of ur amp.(Ur AMP supply voltage/Gain shud give u an approximate figure.)
With the amp connected to the subout of ur AVR listen very carefully if there is any Faint signal.(other than hum.)
Does the sub cone Flap around with the hum or ..is it gentle..?
Try setting the AVR to 2.1 mode. ( i dont remember if this is what the exact terminology was.The setup basically drives only ur Main speakers and sub..)
Change the front speaker settings to indicate they are small. (Or satelites if there is some similar setting.
My guess is that by doing so, ur AVR will insert an HPF into the Front main channels at the same time increase the Pass Band of the LPF on ur SUB to compensate. Does this setup make any difference to the sound.?
Btw, generally the Sub Out includes an LPF. It need not be a direct tap. In modern recievers they are often output by the DSP sitting inside and hence will have an LPF and some post processing done on on the .1 channel. DPL I/II or any surround format will defenitely have the LPF in place.
Finally when u connect ur DIY radio. how authentic is the LF. Do u really feel that its upto the mark. Try Radiocity. I almost always find al lot of extra bass somewhere...!
ajju
there is no fun if everyting starts working first shot...isnt it...! 😀
A few silly questions from me...!!
1) At what frequency is the test tone?
2) What kind of an amp is your DIY amp.?
Could u please check what frequency does the HPF formed by the input/feedback network of ur amp cutoff?.
(Normally there will be a 6db/oct HPF fromed by one of ur input resistors and ur coupling capacitors.
Common error, wrong value of capacitance. If the capcitance is too low ur Low Frequencies will be affected.
Also Please check that ur AMP output does NOT have any DC componets in it.
3) Does the AMP hum when its input is kept floating and the Volume control is set to MAX.?
4) Test 1. Reduce the volume on your sub amp. Try touching the active input alone.
Does that produce any hum.. ( be very careful with this experiment and perform it at low volume, bare foot and only
on solid state AMP's)
Does this produce a hum.? Try increasing the volume till about half till u hear a hum.!
If the PSRR of ur amp is high there are less chances that u'll hear a loud hum.
5)Try connecting this amp/speaker input to one of the unused Line level outputs. Does that make any sound.
6) If there is a hum try touching the ground/sheild of the RCA(still connected to the AVR), standing barefoot.Does that take away the hum.If yes there is a grounding/shielding problem.
7) Also check if u have not accidentally inverted the polarity of ur input cord.
Is it true that u dont hear any sound at all when u have connected ur AMP to the subwoofer output on the AVR.
Does ur normal sub produce enough volume. Check what is the inpit signal level specified in its manual.
Check the input sensitivity of ur amp.(Ur AMP supply voltage/Gain shud give u an approximate figure.)
With the amp connected to the subout of ur AVR listen very carefully if there is any Faint signal.(other than hum.)
Does the sub cone Flap around with the hum or ..is it gentle..?
Try setting the AVR to 2.1 mode. ( i dont remember if this is what the exact terminology was.The setup basically drives only ur Main speakers and sub..)
Change the front speaker settings to indicate they are small. (Or satelites if there is some similar setting.
My guess is that by doing so, ur AVR will insert an HPF into the Front main channels at the same time increase the Pass Band of the LPF on ur SUB to compensate. Does this setup make any difference to the sound.?
Btw, generally the Sub Out includes an LPF. It need not be a direct tap. In modern recievers they are often output by the DSP sitting inside and hence will have an LPF and some post processing done on on the .1 channel. DPL I/II or any surround format will defenitely have the LPF in place.
Finally when u connect ur DIY radio. how authentic is the LF. Do u really feel that its upto the mark. Try Radiocity. I almost always find al lot of extra bass somewhere...!
ajju
Ajju, big one.
When I plug in my fm radio (or cd player) and play radio city with my amp+ woofer (with crossover) all is fine and there is no trace of hum at all. But when I connect the subwoofer pre-out from the receiver to the same amp with the same woofer and crossover, there is a lot of hum. I would not get a clear radio city signal if the amp or the woofer was at fault, right?
Probably the lack of an active LPF is causing the problem in my case? But as you say, most modern receivers have an lpf, it looks like a grounding problem?
By the way, do you think the akai subwoofer (SS 800, SS 830) is a good buy?
When I plug in my fm radio (or cd player) and play radio city with my amp+ woofer (with crossover) all is fine and there is no trace of hum at all. But when I connect the subwoofer pre-out from the receiver to the same amp with the same woofer and crossover, there is a lot of hum. I would not get a clear radio city signal if the amp or the woofer was at fault, right?
Probably the lack of an active LPF is causing the problem in my case? But as you say, most modern receivers have an lpf, it looks like a grounding problem?
By the way, do you think the akai subwoofer (SS 800, SS 830) is a good buy?
1. Ok, test tone frequency is unknown since it is from the receiver.
2. Amp is a diy amp from EFY.
3. A small hum when there is a floating input socket but not considerable.
4. Polarities of all wiring is okay.
There is a loud hum but no signal at all. However, the test tone is heard at a very low volume. The cone is vibrating due to the hum.
2. Amp is a diy amp from EFY.
3. A small hum when there is a floating input socket but not considerable.
4. Polarities of all wiring is okay.
have to try this.
There is a loud hum but no signal at all. However, the test tone is heard at a very low volume. The cone is vibrating due to the hum.
When I plug in my fm radio (or cd player) and play radio city with my amp+ woofer (with crossover) all is fine and there is no trace of hum at all.
Crossover.? u mean after the Sub Amp. Ok talking out of context
Its not recomended to put a crossover after the AMP in a Sub woofer.
Reasons being u can easily equalise actively and second the crossover which essentially will be a coil is quite lossy. A sub amp normally works at high power levels.
But when I connect the subwoofer pre-out from the receiver to the same amp with the same woofer and crossover, there is a lot of hum. I would not get a clear radio city signal if the amp or the woofer was at fault, right?
Yes true. Question.?
Is the FM radio or CD Player a portable one. Working from batteries.?
Have u tried connecting some other Powered Amp to the AVR out. How does it sound.
Sub out
Yes a Subout does have an LPF in place. That is the general tradition. Especially if the Sub out is generated from a DSP(which will be the case generally) it is bound to have an LPF.
When ur sure that a CD or tuner works quite fine and u have explored all possibilities on the AVR setup i woud reccomend that u have the concerned ppl from ProFx check it out...
or may be even u can carry it to profx showroom and get it checked so that they wont start finding faults with u experimenting ...🙂
PS: We can take this offline if required so that we dont burden the forum with our discussion 🙂 and may be we can collate and post our findings later. If yes let me know, I shall mail u.
ajju
Crossover.? u mean after the Sub Amp. Ok talking out of context
Its not recomended to put a crossover after the AMP in a Sub woofer.
Reasons being u can easily equalise actively and second the crossover which essentially will be a coil is quite lossy. A sub amp normally works at high power levels.
But when I connect the subwoofer pre-out from the receiver to the same amp with the same woofer and crossover, there is a lot of hum. I would not get a clear radio city signal if the amp or the woofer was at fault, right?
Yes true. Question.?
Is the FM radio or CD Player a portable one. Working from batteries.?
Have u tried connecting some other Powered Amp to the AVR out. How does it sound.
Sub out
Yes a Subout does have an LPF in place. That is the general tradition. Especially if the Sub out is generated from a DSP(which will be the case generally) it is bound to have an LPF.
When ur sure that a CD or tuner works quite fine and u have explored all possibilities on the AVR setup i woud reccomend that u have the concerned ppl from ProFx check it out...
or may be even u can carry it to profx showroom and get it checked so that they wont start finding faults with u experimenting ...🙂
PS: We can take this offline if required so that we dont burden the forum with our discussion 🙂 and may be we can collate and post our findings later. If yes let me know, I shall mail u.
ajju
Would u mind posting a Schematic of the amp.
I really dont know if all those copyright thingys have to be adhered to...:-?
If yes let me know. I shall collect it via mail.
Lets c what best we can make out of it...!
ajju
I really dont know if all those copyright thingys have to be adhered to...:-?
If yes let me know. I shall collect it via mail.
Lets c what best we can make out of it...!
ajju
Ok, let's take it offline. But just one more post.
I connected another line level output to one channel of the amp and the same hum is present. I touch the ground, no change. But I touch the other channel positive, then there is a little increase in hum. All the while, my bare foot is on the floor. Same problem with another woofer, without any coils, etc.
I suspect a faulty receiver. Maybe I will just take it to the showroom.
Again, have you seen the Akai HT speaker system? Is it worth trying? AV Max thinks it is good.
I connected another line level output to one channel of the amp and the same hum is present. I touch the ground, no change. But I touch the other channel positive, then there is a little increase in hum. All the while, my bare foot is on the floor. Same problem with another woofer, without any coils, etc.
I suspect a faulty receiver. Maybe I will just take it to the showroom.
Again, have you seen the Akai HT speaker system? Is it worth trying? AV Max thinks it is good.
wha tis teh model of the AVR? If Pro FX does nto help let me know. I will make a noise at the Times show on 7th nov. send me details (when and where did you get it, model number, serial number, etc...) so i can hand it over to them. u have 2 days.
Hi...
Just encountered this thread today. Great fun. 🙂
Navin, please count me in the list of Bombay DIY audio chaps, even if I do very little DIY. 🙂
Regarding driver availability, thought I'd put in my two bits.
And Navin, what happened to the group import of Vifa? I'd love to get a good mid-bass and tweeter at the prices mentioned. I find the Peerless India 60W fabric dome tweeter very good, though. Unless I'm being funded by a rich uncle, I'd probably not look for a more expensive tweeter. Clean mid drivers are much harder to find in India. I'd probably go for good Fostex or Jordan full-range and use them as mids. The Bolton mids seem to vary very widely from piece to piece.
Just my inexperienced ten paise of perspective. 🙂
Tarun
Just encountered this thread today. Great fun. 🙂
Navin, please count me in the list of Bombay DIY audio chaps, even if I do very little DIY. 🙂
Regarding driver availability, thought I'd put in my two bits.
- I feel very uncomfortable plonking down good money for drivers whose antecedents one can't even ascertain. For instance, I've seen Peerless woofers being sold in L.Rd whose model numbers you can't correlate to anything on any Website, let alone T/S parameters. I'm okay buying Philips dual-cone FR drivers (Rs.220/ea) or Peerless dome tweeters (Rs.500/ea) without much documentation, but woofers (Rs.2000/ea and more) make me queasy, specially since I know it's tough to use these drivers without good T/S params. Some of you would probably be very comfortable with the thought of buying the Peerless woofers from this shop on the first flr of a bldg in L.Rd, pay in cash, not get a bill, and then find your own way with them by measuring the T/S params and trusting to God about the power rating. I'd feel nervous. I'd rather save up and buy some branded driver which other DIYers on this forum will have worked with. Is this just my inexperience showing? 🙂
- For the first time, I'm seeing imported woofers in Bombay, being sold with full T/S params, detailed docs, and a pucca bill and sales tax receipt. Narains on L.Rd sells Selenium and RCF drivers, and The Absolute Shop sells RCF drivers (and LOTS else). It's a good feeling doing legal business. BTW, I am told RCF woofers are very high quality. Narains are very prompt in answering email.
- One chap in L.Road sells Philips 10" and 12" woofers. I've seen them; they're reasonably well made but with very stiff pleated fabric surrounds, thus indicating probably very high Qts, and of course, no T/S params. The label on the pole piece said "140W RMS" and the price was Rs.1500/ea. They look like Philips, in the sense that a label with the Philips logo and address is stuck on the carton. If you believe that the Philips 8" full-range driver is from Philips, you'll also believe in the origin of these woofers. If I wanted to buy these drivers, I'd probably save up and buy Selenium 12PW3 for Rs.2800/ea + taxes. Much more sturdy mechanically, same high Qts, same low Xmax, higher power handling. Or if I had to work with the Philips drivers, I'd have to measure T/S params for each driver accurately, get the Qts and Fs, and then sit down and design my enclosures, deciding at that time whether to go sealed, ported or dipole. No kidding.
- One guy on L.Rd sells Peerless woofers. He has fading photocopies of datasheets for some of these models. If I remember right, they are in the Rs.1600-2500 price range for 10" and 12" models. Rubber surround, Qts in the 0.3-0.5 range. Angshu may remember more details.
- Bolton woofers are available too; I've seen a 12" 60W rated driver with rubber surround and paper cone, Rs.1200/ea. Have not measured its T/S params. Angshu says one shouldn't trust the power rating of Bolton drivers, though. He also says their poly cone midranges (6.5") are pretty good; he's used them. And I trust Angshu; he's clocked 35 years of serious DIY audio. 🙂 All these Bolton drivers are available from Chowdhury Trading on L.Rd.
And Navin, what happened to the group import of Vifa? I'd love to get a good mid-bass and tweeter at the prices mentioned. I find the Peerless India 60W fabric dome tweeter very good, though. Unless I'm being funded by a rich uncle, I'd probably not look for a more expensive tweeter. Clean mid drivers are much harder to find in India. I'd probably go for good Fostex or Jordan full-range and use them as mids. The Bolton mids seem to vary very widely from piece to piece.
Just my inexperienced ten paise of perspective. 🙂
Tarun
No, the receiver is okay. Today, I took it to the ProFx showroom and they checked it out for me. Perhaps it is a problem with my diy amp.
Re: Hi...
I too feel uncomfortable plunking down good money for goods of unknown origin and specs that is why i am working on this vifa import. unfortunately for vifa to be intreested the quantity must be bulk and hence i am tying to convince friends in the biz. I would prefer a smaller speaker but a 2" (bose type) full ranges and 6" 2 ways are what have largest public demand.
I am looking at both options. trying to convince friends about the viability of a Vifa 6" 2way while trying to convicne others to consider the 3" TB (W3-847 I think). Once we have a bulk buyer then we can add our small quantities to this order. i will post on this forum when i get something going.
For the bass I am considering talking to Palesha on Friday at about 3pm at Taj Lands end. the 12" he has might be viable. I have a small window of time on Friday (3-5pm).
As far as teh Selenium 12" are concerned I would have looked at them for dipole (considering the high Qts) but their Low Xmax leaves me wondering what kid of SPL at 50Hz or 40Hz they are capable of.
I would like to know about Angshu's 6" Bolton expereince. It might be aviable alternate to the Vifa TC series 6". Atleast it is available locally and mating this with the philips dome (rs. 500) might make a good 6" 2 way. angshu, tarun, what do u think?
presently (due to WAF) I am looking at building a system that is smaller than my present 44" x 12" x 16" "monsters". Angshu and George seems the be the seniors here.
Tarun where can i get the philips dome you mentioned? I have a friend who blew out his tweeters on a circa1982 Boston Acoustics 6" 2way (A60). maybe the philips dome will prove a viable alternate. Maybe the Bolton 6" can replace the existing 6" the box is in very good shape and has it's orignal polish still on it.
tcpip said:
I too feel uncomfortable plunking down good money for goods of unknown origin and specs that is why i am working on this vifa import. unfortunately for vifa to be intreested the quantity must be bulk and hence i am tying to convince friends in the biz. I would prefer a smaller speaker but a 2" (bose type) full ranges and 6" 2 ways are what have largest public demand.
I am looking at both options. trying to convince friends about the viability of a Vifa 6" 2way while trying to convicne others to consider the 3" TB (W3-847 I think). Once we have a bulk buyer then we can add our small quantities to this order. i will post on this forum when i get something going.
For the bass I am considering talking to Palesha on Friday at about 3pm at Taj Lands end. the 12" he has might be viable. I have a small window of time on Friday (3-5pm).
As far as teh Selenium 12" are concerned I would have looked at them for dipole (considering the high Qts) but their Low Xmax leaves me wondering what kid of SPL at 50Hz or 40Hz they are capable of.
I would like to know about Angshu's 6" Bolton expereince. It might be aviable alternate to the Vifa TC series 6". Atleast it is available locally and mating this with the philips dome (rs. 500) might make a good 6" 2 way. angshu, tarun, what do u think?
presently (due to WAF) I am looking at building a system that is smaller than my present 44" x 12" x 16" "monsters". Angshu and George seems the be the seniors here.
Tarun where can i get the philips dome you mentioned? I have a friend who blew out his tweeters on a circa1982 Boston Acoustics 6" 2way (A60). maybe the philips dome will prove a viable alternate. Maybe the Bolton 6" can replace the existing 6" the box is in very good shape and has it's orignal polish still on it.
http://www.baazee.com/jsp/BidForm.jsp?Trade_TradeId=23831282. What's the catch?
I have to admit, this is tempting.
I have to admit, this is tempting.
ya me too...!!
btw vivek...i had send u an email...did u recieve it or was it lost in cyberspace...?
btw vivek...i had send u an email...did u recieve it or was it lost in cyberspace...?
Sub woofer out
Vivek
I just came across this thread..Do you have an active crossover in the signla path before your sub amp? Or is the AVR sub out connected directly to the amp ?
I have an Onkyo DD/DTS AVR as well as two amps for audio. All use active crossovers for subwoofer duty.
George
Vivek
I just came across this thread..Do you have an active crossover in the signla path before your sub amp? Or is the AVR sub out connected directly to the amp ?
I have an Onkyo DD/DTS AVR as well as two amps for audio. All use active crossovers for subwoofer duty.
George
The link is not working now. It was a Torvin six-speaker package for HT. The original price was listed as 12k but they are giving it away for a little more than 6K.
Ajju, I did not get the e-mail. My id is cqd@rediffmail.com.
George, The ProFx people said there is a LPF in the subwoofer pre out. So I connected the amp directly. Maybe I need to connect a LPF to make sure. But I took the receiver to the showroom and the sub channel was working fine.
Ajju, I did not get the e-mail. My id is cqd@rediffmail.com.
George, The ProFx people said there is a LPF in the subwoofer pre out. So I connected the amp directly. Maybe I need to connect a LPF to make sure. But I took the receiver to the showroom and the sub channel was working fine.
do you have a spare ampto replce the diy amp? any size or wattage. my guess is you gotta look there. mostly for a floating ground or groud loop. but u say you get no music whatsoever so that confuses me.
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