I have now gotten my hands on a Helix p-DSP cheaply and a SPL-Dynamics ice-150.4 amp for my front speakers. I plan on making my Alpine SPR-50c speakers active. I have a kicker DX125.2 laying around and have planned on adding rear speakers.
Now I have heard from all the audiophiles to not bother with rear speakers, but I found the right way to do it. Now I don't know how to implement it.
First the rears should be band-pass eq:ed from +-200hz to +-7khz and 20+ms of delay should be added. Then the right signal should be added out of phase to the left signal and vise versa. This should make it so that they don't play any centered sounds like vocals, that exist in both L and R signals. This is pretty much what the early Dolby Pro Logic processing did.
The problem is, how do I do this. Only the newer Helix DSP processors seem to have this function in the input mixer. And the other way is to use balanced signals and just cross the signal wires. But I don't have either, to my knowledge.
Would there be an easy way to implement something like this? And if so, should I use coaxials or midbass speakers in my rear deck?
Now I have heard from all the audiophiles to not bother with rear speakers, but I found the right way to do it. Now I don't know how to implement it.
First the rears should be band-pass eq:ed from +-200hz to +-7khz and 20+ms of delay should be added. Then the right signal should be added out of phase to the left signal and vise versa. This should make it so that they don't play any centered sounds like vocals, that exist in both L and R signals. This is pretty much what the early Dolby Pro Logic processing did.
The problem is, how do I do this. Only the newer Helix DSP processors seem to have this function in the input mixer. And the other way is to use balanced signals and just cross the signal wires. But I don't have either, to my knowledge.
Would there be an easy way to implement something like this? And if so, should I use coaxials or midbass speakers in my rear deck?
Rod Elliot has a couple of projects you might want to look at.
One with an adjustment that bleeds out of phase signal into the opposite channel, with a pot to vary the amount. I had a Sanyo equalizer with that exact feature back in the 80's, it was neat. I really enjoyed it until some punk ripped it out of my dash overnight.
He also has a project that extracts a straight difference signal à la Hafler, which is what you mention.
Check out... Project 18 and Project 21
One with an adjustment that bleeds out of phase signal into the opposite channel, with a pot to vary the amount. I had a Sanyo equalizer with that exact feature back in the 80's, it was neat. I really enjoyed it until some punk ripped it out of my dash overnight.
He also has a project that extracts a straight difference signal à la Hafler, which is what you mention.
Check out... Project 18 and Project 21
The schematic in figure 3 is complete except for the power supply, and could be built for a few bucks on perfboard with a modest amount of soldering and wire connections.
Do you have any experience with this sort of thing, or is it totally unfamiliar?
Do you have any experience with this sort of thing, or is it totally unfamiliar?
I do have some kind of experience with soldering and electronics. But not so much reading schematics. If I looked into it more and could make a parts list, I could probably solder that together myself, if it is inexpensive enough.
But I don't know how much I would trust on the quality of that. I'm seeking for a pretty high standard of sound quality in my car and don't know how much volume that circuit can take, how much noise it would pick up from everything else etc.
What I know, the newer Helix processors have this feature, but they are very expensive. I bought the P-DSP for a very good price, because it has almost everything that the newer ones have.
The P-DSP uses their DSP PC-tool V2; DSP PC-Tool Version 2 | Audiotec Fischer
You can go there and see all the features for my DSP. I could not find anything for phase swapping etc.
It would probably be possible to just add with a firmware update, but I don't think Audiotec Fischer wants to put such time and effort for and old product.
Also, I would like to be able to change the amount of rear-fill/ rear-music.
I will have passengers in the back seat quite often, so I would like to be able to turn on just music in the back, and not just rear-fill.
By the way, what would work best in this scenario, 8" mids or 6x9" coaxials?
I will put them on the rear deck and build a small enclosure for them underneath.
I will have passengers in the back seat quite often, so I would like to be able to turn on just music in the back, and not just rear-fill.
By the way, what would work best in this scenario, 8" mids or 6x9" coaxials?
I will put them on the rear deck and build a small enclosure for them underneath.
I have heard people like focal speakers. But the only 8" mids I found in Finland are Focal Universal 8" mids.
I have looked at Hertz's new 8" mids. They look like they can take a lot more power.
I have a SPL dynamics 4x150W A/B amp now powering my Alpine type R front speakers on two channels. I also have a Kicker 2x30W class-D amp.
I plan on going active for the front speakers. The Kicker amp would be enough for the tweeters because of their good efficiency, and then I'd get some kick out of the 8" mids, but the class-A/B amp would probably have better quality for the tweeters.
I have looked at Hertz's new 8" mids. They look like they can take a lot more power.
I have a SPL dynamics 4x150W A/B amp now powering my Alpine type R front speakers on two channels. I also have a Kicker 2x30W class-D amp.
I plan on going active for the front speakers. The Kicker amp would be enough for the tweeters because of their good efficiency, and then I'd get some kick out of the 8" mids, but the class-A/B amp would probably have better quality for the tweeters.
I have no experience of the Hertz speakers and so I can’t comment on them but I use a pair of the 8” integration Woofers installed as dedicated mid basses from 80-250 abs in the underseat position in my BMW and they sound fantastic for the money.
They have a high sensitivity and running from a bridged Sony XM3040, around a 100-120 W RMS, they cope quite well.
I find that speakers with higher power handling tend to have lower sensitivity and that it all tends to balance out in terms of SPL, but with the more sensitive speaker tending to sound better due to fewer compromises for handling.
They have a high sensitivity and running from a bridged Sony XM3040, around a 100-120 W RMS, they cope quite well.
I find that speakers with higher power handling tend to have lower sensitivity and that it all tends to balance out in terms of SPL, but with the more sensitive speaker tending to sound better due to fewer compromises for handling.
I agree that speakers with higher sensitivity might sound better, but often only because they are louder. And louder speakers sound better.
For example my Alpine SPR-50c front speakers have a sensitivity of 87dB, but when given that 2x150W RMS, they sound fantastic.
Although when a higher sensitivity speaker would take that much power, it would probably sound better.
The thing is, that coaxial speakers are a lot easier to find around here, especially for a good price on the used market. Would they not play the same purpose as mids, only with a low-pass-filter from the DSP?
My Alpine speakers have good "kick" bass. I could e.g. buy a pair of type-R 6x9" coaxials for the rear-deck for a good price. And they should fit the sound-signature better?
But on the other hand I have heard that the JBL GTO 939 speakers play very well and sound natural.
For example my Alpine SPR-50c front speakers have a sensitivity of 87dB, but when given that 2x150W RMS, they sound fantastic.
Although when a higher sensitivity speaker would take that much power, it would probably sound better.
The thing is, that coaxial speakers are a lot easier to find around here, especially for a good price on the used market. Would they not play the same purpose as mids, only with a low-pass-filter from the DSP?
My Alpine speakers have good "kick" bass. I could e.g. buy a pair of type-R 6x9" coaxials for the rear-deck for a good price. And they should fit the sound-signature better?
But on the other hand I have heard that the JBL GTO 939 speakers play very well and sound natural.