Kilentra said:
http://www.audax-speaker.de/rd-line.pdf (older RDxx documentation with more details...)
---------------------------------------------------------------------------------
Here's another nice read (contains some old usenet postings on bass issues):
http://members.ozemail.com.au/~googong/spn.html
carlosfm said:
Is this normal for ONE 25cm woofer on a sealed box?
My Sub.
Only found this page and no further details: http://www.tecnosoundsanremo.it/it/dept_235.html
Well, not quite
Can I have the TS parameters? Did you test it in room (cars act as bandpass boxes AFAIK) for usable output at let's say 25Hz?lucpes, I mean, I made a home sub with a car audio speaker.
Hardstone's site is: http://www.hsaudio.com, but it's a pain to find anything there.
I have the catalog on paper at home, tonight I'll post the woofer's TS parameters (they are impressive).
I have the woofer firing down, so what you see is a black cube box.
And the sound is amazing.
Deep and controled like there's no tomorrow.
Hardstone's site is: http://www.hsaudio.com, but it's a pain to find anything there.
I have the catalog on paper at home, tonight I'll post the woofer's TS parameters (they are impressive).
I have the woofer firing down, so what you see is a black cube box.
And the sound is amazing.
Deep and controled like there's no tomorrow.
Hardstone HS V110 TS parameters
Here it goes:
Size - 250cm / 10"
Magnet weight - 80 Oz
Freq. resp. - 22-3000hz
RMS power - 375w
Max. power - 750w
Voice coil diameter - 2"
Sensitivity - 89db
Impedance - 4+4 ohm (I use the two in series for 8 ohms)
FS - 22 hz
Re - 3.6 ohms
Qts - 0.49
Qms - 6.16
Qes - 0.53
Vas (Lt.) - 31
Xmax - 20mm
What about this?
Here it goes:
Size - 250cm / 10"
Magnet weight - 80 Oz
Freq. resp. - 22-3000hz
RMS power - 375w
Max. power - 750w
Voice coil diameter - 2"
Sensitivity - 89db
Impedance - 4+4 ohm (I use the two in series for 8 ohms)
FS - 22 hz
Re - 3.6 ohms
Qts - 0.49
Qms - 6.16
Qes - 0.53
Vas (Lt.) - 31
Xmax - 20mm
What about this?
Interesting choice, thanks!
The winisd graph sure looks interesting (quite similar to the NHT1259 - I did some mistakes with my graph, both are -3dB@~30Hz in closed boxes, albeit this needs a smaller one) but it figures that it has a pretty high Le, so using it for more than 100Hz (the NHTs will go up to 300Hz with no problem) is a big no-no.
I'm still trying find out if I can skip the midwoofer array and go for a good pair of woofers (2 per side) crossed directly to the RD50 or RD75s.
Still cooking!
The winisd graph sure looks interesting (quite similar to the NHT1259 - I did some mistakes with my graph, both are -3dB@~30Hz in closed boxes, albeit this needs a smaller one) but it figures that it has a pretty high Le, so using it for more than 100Hz (the NHTs will go up to 300Hz with no problem) is a big no-no.
I'm still trying find out if I can skip the midwoofer array and go for a good pair of woofers (2 per side) crossed directly to the RD50 or RD75s.
Still cooking!
Hi lucpes:
I'd strongly suggest ditching the idea of coupling two normal-sized woofers per side with the RD75 or even the RD50. My RD75 system started with two bass boxes each having two 8" vifa woofers. The bass never integrated properly with the line source. That was the reason why I decided to try dipolar arrays of subwoofer drivers. Each of the two diplolar subs has four 18" subwoofer drivers made by Eminence (I got them at a great clearance price and I think they are no longer availble). The sub drivers are stacked up on a simple open baffle, and the array is about the hight of the RD75 driver. This effectively solved the problem of integrating the bass with the mid, at least in terms of radiation patterns. While playing some drum music (e.g., Japanese Taiko), I can stand 2ft in front of the RD75 driver, and the drum beats would appear to be all coming from the RD75 driver, instead of the bass drivers. I don't think you can get that kind of integration using two small woofers sitting close to the ground. Using arrays of small midwoofers in either sealed boxes or open baffles may be a good idea, but I have not tried it yet.
Regards,
Kurt
I'd strongly suggest ditching the idea of coupling two normal-sized woofers per side with the RD75 or even the RD50. My RD75 system started with two bass boxes each having two 8" vifa woofers. The bass never integrated properly with the line source. That was the reason why I decided to try dipolar arrays of subwoofer drivers. Each of the two diplolar subs has four 18" subwoofer drivers made by Eminence (I got them at a great clearance price and I think they are no longer availble). The sub drivers are stacked up on a simple open baffle, and the array is about the hight of the RD75 driver. This effectively solved the problem of integrating the bass with the mid, at least in terms of radiation patterns. While playing some drum music (e.g., Japanese Taiko), I can stand 2ft in front of the RD75 driver, and the drum beats would appear to be all coming from the RD75 driver, instead of the bass drivers. I don't think you can get that kind of integration using two small woofers sitting close to the ground. Using arrays of small midwoofers in either sealed boxes or open baffles may be a good idea, but I have not tried it yet.
Regards,
Kurt
lucpes,
Here are the pictures of my new all-dipole system. It stands at 76.5 inches tall.
The midrange baffle has four 10-inch drivers; - they are SS25W8565 wired in the series-parallel manner. The midrange baffle is 14 inches wide with 3 inch wings folding back. The drivers are held with the back spine, so no bolts are used and it is identical to the Phoenix main baffle design. The woofers are also Phoenix design from S. Linkwitz with Peerless 12-inch XLS 830500 drivers for a total of 4 drivers per channel.
The shape of RD-75 baffle was influenced by the research done by John Wittaker and the article by Tom Pirazella. It is 24 inches at the bottom and 18 inches on top counting the curved part. The straight part of the baffle is one-sided trapezoid with 18 inches on the bottom and 12 inches on top. The RD-75 baffle has no sharp edges anywhere in an effort to minimize the diffraction effects.
It took more then a year to build this system and it is huge. I somehow did not realize how big it was going to be as I was building it.
My homemade amps power the system. I have on hand 4 stereo units that can deliver a clean 500 watts into 4 ohms per channel.
The crossover points for the system are 75 and 400 Hz, all 4th order L-R. I ended up using Behringer units, the DEQ2496 and the DCX2496 to do most of the crossover functions. However, with the system like I built the DCX2496 is not sufficient, as it does not have enough headroom to do the necessary EQ. So, I ended up building an additional analog processor that takes care of open baffle EQ for the woofers and the midrange.
RD-75 EQ is completely handled by the DCX2496. I am using a fair amount of high frequency boost to EQ the RD-75 nearly flat up to 17 kHz. The boost is 10 dB and it is rising exponentially from at about 9 kHz (0 dB) and finishing at 20 kHz (+10 dB).
So, I drive a digital signal from my CD player to the SPDI/F port in the DEQ2496. The DEQ2496 does the RTA duty and it is digitally connected to the DCX2496. The DCX2496 does all the cross-over filtering, all the notch filters and the delays, as well as the dynamic signal control so that I do not overdrive the speakers.
The analog processor is connected to the DCX2496 through the XLR-RCA cables. I attenuate the signal by about 30 dB in the analog processor with resistor dividers and then I do all the EQ with discrete 8-transistor (BJT) op-amps. The signal attenuation is necessary because the output level of the DCX2496 can be as much as 22 dB or about 12 Volts. Also, if you use the DCX’s analog inputs you must ensure that those inputs get at least 8-10 Volts peaks in order to maximize the S/N of the A/D converters.
The real challenge here is a volume control, as usual. I have a working solution using Alps motorized potentiometers. I happened to have a pair of 4-gang Blue pots. So I am working on a remote control set-up that would ultimately become a volume/balance control for my 3-way speakers. The pots are buffered with a 15 dB amplifiers so that there is an ample signal level just before the power amps. This set-up will allow me to have a multi-channel volume control for the HT application as I can add the motorized pots in order to control the signal level going to the Rear and Centre speakers. Perhaps a less involved but an inferior solution is a volume control based on VCA. None the less, for a 3-way speaker system you need 6 fully synchronous pots.
Incidentally, the efficiency of my system components is such that the woofers are about 3 dB higher then the RD-75 and the midrange is about 10 dB higher then the RD-75. Although this can be taken care by the DCX2496 level adjustment, it is better not use those controls for more then a few dBs, as it has an impact on the resolution. So I do most level adjustments with resistor attenuators in an analog processor and fine level adjustments with the DCX2496.
The overall gain structure is very important so that no components in the signal chain ever experiences clipping. With dipole system you can easily have a near 30 db of EQ requirements as in Phoenix woofers case. For my midrange I use a shelving low-pass with about 30 db at 20 Hz and 3 dB at 550 Hz. I am still fine-tuning those numbers.
Here are the pictures of my new all-dipole system. It stands at 76.5 inches tall.
An externally hosted image should be here but it was not working when we last tested it.
The midrange baffle has four 10-inch drivers; - they are SS25W8565 wired in the series-parallel manner. The midrange baffle is 14 inches wide with 3 inch wings folding back. The drivers are held with the back spine, so no bolts are used and it is identical to the Phoenix main baffle design. The woofers are also Phoenix design from S. Linkwitz with Peerless 12-inch XLS 830500 drivers for a total of 4 drivers per channel.
The shape of RD-75 baffle was influenced by the research done by John Wittaker and the article by Tom Pirazella. It is 24 inches at the bottom and 18 inches on top counting the curved part. The straight part of the baffle is one-sided trapezoid with 18 inches on the bottom and 12 inches on top. The RD-75 baffle has no sharp edges anywhere in an effort to minimize the diffraction effects.
It took more then a year to build this system and it is huge. I somehow did not realize how big it was going to be as I was building it.
My homemade amps power the system. I have on hand 4 stereo units that can deliver a clean 500 watts into 4 ohms per channel.
The crossover points for the system are 75 and 400 Hz, all 4th order L-R. I ended up using Behringer units, the DEQ2496 and the DCX2496 to do most of the crossover functions. However, with the system like I built the DCX2496 is not sufficient, as it does not have enough headroom to do the necessary EQ. So, I ended up building an additional analog processor that takes care of open baffle EQ for the woofers and the midrange.
RD-75 EQ is completely handled by the DCX2496. I am using a fair amount of high frequency boost to EQ the RD-75 nearly flat up to 17 kHz. The boost is 10 dB and it is rising exponentially from at about 9 kHz (0 dB) and finishing at 20 kHz (+10 dB).
So, I drive a digital signal from my CD player to the SPDI/F port in the DEQ2496. The DEQ2496 does the RTA duty and it is digitally connected to the DCX2496. The DCX2496 does all the cross-over filtering, all the notch filters and the delays, as well as the dynamic signal control so that I do not overdrive the speakers.
The analog processor is connected to the DCX2496 through the XLR-RCA cables. I attenuate the signal by about 30 dB in the analog processor with resistor dividers and then I do all the EQ with discrete 8-transistor (BJT) op-amps. The signal attenuation is necessary because the output level of the DCX2496 can be as much as 22 dB or about 12 Volts. Also, if you use the DCX’s analog inputs you must ensure that those inputs get at least 8-10 Volts peaks in order to maximize the S/N of the A/D converters.
The real challenge here is a volume control, as usual. I have a working solution using Alps motorized potentiometers. I happened to have a pair of 4-gang Blue pots. So I am working on a remote control set-up that would ultimately become a volume/balance control for my 3-way speakers. The pots are buffered with a 15 dB amplifiers so that there is an ample signal level just before the power amps. This set-up will allow me to have a multi-channel volume control for the HT application as I can add the motorized pots in order to control the signal level going to the Rear and Centre speakers. Perhaps a less involved but an inferior solution is a volume control based on VCA. None the less, for a 3-way speaker system you need 6 fully synchronous pots.
Incidentally, the efficiency of my system components is such that the woofers are about 3 dB higher then the RD-75 and the midrange is about 10 dB higher then the RD-75. Although this can be taken care by the DCX2496 level adjustment, it is better not use those controls for more then a few dBs, as it has an impact on the resolution. So I do most level adjustments with resistor attenuators in an analog processor and fine level adjustments with the DCX2496.
The overall gain structure is very important so that no components in the signal chain ever experiences clipping. With dipole system you can easily have a near 30 db of EQ requirements as in Phoenix woofers case. For my midrange I use a shelving low-pass with about 30 db at 20 Hz and 3 dB at 550 Hz. I am still fine-tuning those numbers.
mac,
The listening comparative tests are always extremely subjective and to be somewhat fair you must have both systems on hands powered up with the same electronics with levels equalized to within 0.1 dB.
Naturally, my impressions are far from scientific and again purely subjective. Am I biased? No, absolutely not!
To my ears this is the best sound yet. All I can say that I recently had a chance to listen to BW Nautilus speakers that a local high-end dealer had on display. This is a $30k (Can.) deal with great-looking clam-shell cabinets. The electronics used to power the Nautilus was a mega-buck mega-watt class-A affair from Levinson along with a 10k CD player. I was impressed with the sound; however, my system had a by far better ‘presents’ and more articulate bass in my view.
The listening comparative tests are always extremely subjective and to be somewhat fair you must have both systems on hands powered up with the same electronics with levels equalized to within 0.1 dB.
Naturally, my impressions are far from scientific and again purely subjective. Am I biased? No, absolutely not!
I got into the 'ribbon' game quite a while ago, with the Carver Ribbon/NHT 1259 combo that was popular on the Bass/DIY Loudspeakers list. The Carver is a 60" planar which is a precursor to the current BG drivers.
Although my system has been very unstable over the years with my DSP xover experiments , moving etc, count me as another that would advise against trying to directly integrate from a true woofer to the ribbon - it's just not going to work well. I'm currently using an line/array of 4 7" midbass drivers alongside the ribbons with a target xover of ~350. I'm still dialing it in, but it clearly integrates much better. I'd also tend to vote that these drivers benefit from tweeters, but the Carver has worse HF rolloff than the BG's, so you might be able to get away with eq/boost.
BTW - If anyone is interested in trying this out on the (relatively) cheap, PM me - I'm concluding that these guys are just too freakin big for my tiny room, so might be interested in selling the drivers .
Although my system has been very unstable over the years with my DSP xover experiments , moving etc, count me as another that would advise against trying to directly integrate from a true woofer to the ribbon - it's just not going to work well. I'm currently using an line/array of 4 7" midbass drivers alongside the ribbons with a target xover of ~350. I'm still dialing it in, but it clearly integrates much better. I'd also tend to vote that these drivers benefit from tweeters, but the Carver has worse HF rolloff than the BG's, so you might be able to get away with eq/boost.
BTW - If anyone is interested in trying this out on the (relatively) cheap, PM me - I'm concluding that these guys are just too freakin big for my tiny room, so might be interested in selling the drivers .
Many thanks for your detailed replies, now I have something to chew
Noted (again) the midwoofer array - thanks to everyone who pointed this out;
Here's what I 'narrowed' my choices to:
- digital out to Behringer DEQ2496->dig out
- Behringer DCX2496 (analog out -> fixed voltage divider resistors->pots for volume control-amps)
- Woofer choices: 8xPeerless 12-inch XLS in Phoenix dipole configuration (4 per side)
- midwoofer: 12xPEERLESS 850490 HDS 8" (low midrange distortion) (dipole, 6 per side, on top of the bass units, maybe in a slightly wider baffle than Vadim has
- amplifiers (woofers and midwoofers): Zappulse 2.2 ( http://www.lcaudio.dk/com/zp2.htm ); for the woofer amps - build a linkwitz transform circuit;
- 2xRD75's
- RD75 amps: 2xOPTIMOS kits from Randy Slone
- trying to locate a good 6-gang pot for volume control
@Vadim - I'd be very interested in more pics/details on the ribbon baffles (eg: thickness) - great job btw, because if the sound is half as good as they look you really have something comparable to $30K+ commercial offerings. All I can really say is - wow
Best regards,
lucpes
Noted (again) the midwoofer array - thanks to everyone who pointed this out;
Here's what I 'narrowed' my choices to:
- digital out to Behringer DEQ2496->dig out
- Behringer DCX2496 (analog out -> fixed voltage divider resistors->pots for volume control-amps)
- Woofer choices: 8xPeerless 12-inch XLS in Phoenix dipole configuration (4 per side)
- midwoofer: 12xPEERLESS 850490 HDS 8" (low midrange distortion) (dipole, 6 per side, on top of the bass units, maybe in a slightly wider baffle than Vadim has
- amplifiers (woofers and midwoofers): Zappulse 2.2 ( http://www.lcaudio.dk/com/zp2.htm ); for the woofer amps - build a linkwitz transform circuit;
- 2xRD75's
- RD75 amps: 2xOPTIMOS kits from Randy Slone
- trying to locate a good 6-gang pot for volume control
@Vadim - I'd be very interested in more pics/details on the ribbon baffles (eg: thickness) - great job btw, because if the sound is half as good as they look you really have something comparable to $30K+ commercial offerings. All I can really say is - wow
Best regards,
lucpes
lucpes,
I am convinced that you will not be disappointed with the sound of the dipole system.
I went through the same soul-searching before I settled on the choice of drivers and overall system configuration. Like everything else in engineering, the system you will build is always a collection of compromises.
I fact Tom Pezarella, whose initial article inspired me to build my system, uses an IB subs built into the wall. The dipole bass is very articulate and, unlike the sealed bass, it does not sound like the same note all the time. It sounds a lot like the bass I am used to in a life concert. However, the trade-off here is SPL and very low frequency extension. There is no way to make it as loud as you may need to for the HT, unless you end up using an insane numbers of woofers. Certainly you will need more then 4 Peerless woofers pert side, perhaps 8 or 12 to approach the kind of SPL you may need for the HT. With 4 woofers per side it still sounds great but I find that I would like more for HT only, not for music though.
I am thinking about a pair of sonotubes for the 15-40 Hz range. We will see…
As for the volume control, there are several choices, depending if you want to have it as an IR remote. If not, 2 step attenuators can be built on 3-section switches. If you can locate 4-gand attenuators, several places on the web sell them, that will do just as well, - 1 per channel.
My solution is a combination of 4-gang and 2-gang Alps Blue motorized pots. I use the 4-gang for the 3-way front channels and duals for the rear channels (Carver Plat IV) and Center channel (Tannoy 10-inch concentric). I am building a Control Center where the IR electronics and relay switching circuit will be housed. The pots will reside in 3 separate enclosures and their motors will be connected to the control center with a standard RCA wire. The enclosures contain simple 2-channel pre-amps powered from a single transformer but with separate voltage regulators. This way I can select to control each pot individually or all at once. Also the set-up is very modular, it gives the necessary 6-channel source selection capability and I avoid huge boxes. The potential problem with this approach is that the motors may not rotate with the same speed. However, it is rather simple to equalize the rotational speed with 1-Ohm resistors. I managed to do that and my 2-channel prototype is doing well right now.
Naturally, yet for another solution see this
www.diyaudio.com/forums/showthread.php?s=&threadid=12186
Or this,
http://www.decibelhifi.com.au/prod69.htm
Good luck!
I am convinced that you will not be disappointed with the sound of the dipole system.
I went through the same soul-searching before I settled on the choice of drivers and overall system configuration. Like everything else in engineering, the system you will build is always a collection of compromises.
This is an excellent choice as far as woofers go. Certainly it is more then adequate for nearly any music material I can through at it. However, if you plan to use the system for the HT duty as well, then perhaps you will also need to consider an additional sub to augment the very low frequency sounds. This sub will definitely have to be a sealed design.
I fact Tom Pezarella, whose initial article inspired me to build my system, uses an IB subs built into the wall. The dipole bass is very articulate and, unlike the sealed bass, it does not sound like the same note all the time. It sounds a lot like the bass I am used to in a life concert. However, the trade-off here is SPL and very low frequency extension. There is no way to make it as loud as you may need to for the HT, unless you end up using an insane numbers of woofers. Certainly you will need more then 4 Peerless woofers pert side, perhaps 8 or 12 to approach the kind of SPL you may need for the HT. With 4 woofers per side it still sounds great but I find that I would like more for HT only, not for music though.
I am thinking about a pair of sonotubes for the 15-40 Hz range. We will see…
Nothing wrong with those. However, I might be concerned with driving them below 100 Hz. I think that 10-inch units are better suited for that and if memory serves, Linkwitz discussed that on his site and acknowledged that his choice for the 8-inch Scan Speak diver in the Phoenix design was a compromise and the 10-inch would have been a better choice. I fact, in his 4-way system he does use 10-inch drivers for what he calls a ‘lower midrange’. I found that Phoenix wooers do not work well much above 120 Hz. If you cross them lower, as I did, the sound gets a lot better.
You will not be able to do a dipole EQ with the DCX2496 along. At least, I could not. Even if you use the wider baffle then I did, still the EQ for the midrange will have to extend all the way to about 400-450 Hz. That would mean that shelving low-pass filter will have to cover 4-5 octaves. You will end up with a requirement to have about 30 dB of gain at about 12-15 Hz. Certainly the DCX2496 cannot do that. Same logic would apply to the woofers EQ.
As for the volume control, there are several choices, depending if you want to have it as an IR remote. If not, 2 step attenuators can be built on 3-section switches. If you can locate 4-gand attenuators, several places on the web sell them, that will do just as well, - 1 per channel.
My solution is a combination of 4-gang and 2-gang Alps Blue motorized pots. I use the 4-gang for the 3-way front channels and duals for the rear channels (Carver Plat IV) and Center channel (Tannoy 10-inch concentric). I am building a Control Center where the IR electronics and relay switching circuit will be housed. The pots will reside in 3 separate enclosures and their motors will be connected to the control center with a standard RCA wire. The enclosures contain simple 2-channel pre-amps powered from a single transformer but with separate voltage regulators. This way I can select to control each pot individually or all at once. Also the set-up is very modular, it gives the necessary 6-channel source selection capability and I avoid huge boxes. The potential problem with this approach is that the motors may not rotate with the same speed. However, it is rather simple to equalize the rotational speed with 1-Ohm resistors. I managed to do that and my 2-channel prototype is doing well right now.
Naturally, yet for another solution see this
www.diyaudio.com/forums/showthread.php?s=&threadid=12186
Or this,
http://www.decibelhifi.com.au/prod69.htm
Will do. I will take more pictures in a few days and will post them here.
Good luck!
These get my vote for the_most_beautiful_dipoles_I've ever seen!
Thanks for providing the links to the 6 channel volume controls (although the one to the APOX site doesn't seem to work--I only get error messages).
I'm building some active dipoles ala Orion/Bob5 with SEAS mids/tweets and TC Sounds TC2+ woofers, Nakamichi amps (nice muted turn-on/off switching!) and either DBX260 or Behrenger DCX XO/eq (once I finally decide which to go with). I am looking for some sort of passive or active volume control between the XO and amps so it is with great interest that I read all of your highly informative posts.
Again, nice one on your dipoles!
Thanks for providing the links to the 6 channel volume controls (although the one to the APOX site doesn't seem to work--I only get error messages).
I'm building some active dipoles ala Orion/Bob5 with SEAS mids/tweets and TC Sounds TC2+ woofers, Nakamichi amps (nice muted turn-on/off switching!) and either DBX260 or Behrenger DCX XO/eq (once I finally decide which to go with). I am looking for some sort of passive or active volume control between the XO and amps so it is with great interest that I read all of your highly informative posts.
Again, nice one
on your dipoles!
I was probably the first to combine The Carver 60" and dual 1259's. The woofer boxes are a bit larger than normally speced for the 1259 and are therefore lower in Qb. I find that this helps a lot with bass integration with the ribbons. ALL in all , I agree with what a previous poster said about standing next to the units and having the kickdrum seem to come from the ribbon. Spooky in a way.
More here:
http://www.geocities.com/CapeCanaveral/2132/system.htm
An externally hosted image should be here but it was not working when we last tested it.
More here:
http://www.geocities.com/CapeCanaveral/2132/system.htm
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