cjh said:
Could this be due to baffle step?
Yes. the most important benefit of a sub is the improved midrange (assuming active roll-off on the bottom of the satelitte).
Why not just add a sub and leave then as it. Put at least a PLLXO in front of the amp driving the TLs.
dave
The reason I want speakers that go quite low is because when I play music I'm only going to use those two speakers. The sub, center and rears only come into play when I'm going to watch a movie. This way I get good bass with music and when watching a movie my fronts can contribute to the bass as well, which I think is never bad.
Kelticwizard, thanks for those graphs. But, just to be curious, I'm beginning to doubt that there's an actual difference between the HDS and CSX. 😕
Kelticwizard, thanks for those graphs. But, just to be curious, I'm beginning to doubt that there's an actual difference between the HDS and CSX. 😕
planet10 said:
Peerless Pipe was designed for Peerless CSX 176, otherwise known as 850122.
Fs = 38 Hz
Vas = 27.7 liters
Qes = 0.53
Qms = 2.22
Qts = 0.43
Bylie wants to subsititue the Peerless 850439, known as the HDS 182 by some places and the HDS 164 on the Peerless website 😕 😕 :
Fs = 44.9 Hz
Vas = 18.7 liters
Qes = 0.42
Qms = 2.28
Qts = 0.35
To further complicate matters, several threads here in DIY audio as well as the Peerless Pipe website itself make it clear that if you order either one of the Peerless drivers, you are likely to get Thiele-Small parameters similar to the pubished specs for the other one. I modelled both in a 1 cu ft sealed box to illustrate that at least in sealed and ported designs, they all work out pretty close when placed in the box anyway. As for how they work in a Transmission Line, I do not know.
Hopefully, Dave-who runs his own T-Line site, can help us out on this.
And just to add a further air of mystery to the whole situation, the 850439 is listed as the HDS 164 on the Peerless website. However, if you go to the Parts Express website and look for the Peerless section, you are directed to the "Peerless at Parts Express" page where they direct you to a pdf with a Peerless data sheet, complete with Peerless logo printed on it, where the same woofer, 850439, is listed as the Peerless 182.
Since model numbers tend to be related to outside diameter of the speaker frame, did Peerless suddenly decide to deduct 18 mm from the 182's they shipped to their retail outfits? If so, how did Peerless manage to come up with exactly the same Thiele-Small numbers, including Sd, (cone area), when the new speaker was tested?
These are magicks with which even the Keltic Wizard is unfamiliar. 😉 😉
www.peerless.dk
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=137
Hopefully, Dave-who runs his own T-Line site, can help us out on this.
And just to add a further air of mystery to the whole situation, the 850439 is listed as the HDS 164 on the Peerless website. However, if you go to the Parts Express website and look for the Peerless section, you are directed to the "Peerless at Parts Express" page where they direct you to a pdf with a Peerless data sheet, complete with Peerless logo printed on it, where the same woofer, 850439, is listed as the Peerless 182.
Since model numbers tend to be related to outside diameter of the speaker frame, did Peerless suddenly decide to deduct 18 mm from the 182's they shipped to their retail outfits? If so, how did Peerless manage to come up with exactly the same Thiele-Small numbers, including Sd, (cone area), when the new speaker was tested?
These are magicks with which even the Keltic Wizard is unfamiliar. 😉 😉
www.peerless.dk
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=137
164mm is the measurement between the two sides that are truncate. (good thing for a line array!)
182mm is the overall diameter
They are the same driver
182mm is the overall diameter
They are the same driver
kelticwizard said:
The lower Q of the substitute driver would ask for a larger x-section but this would be countered by the smaller Vas. The lower Q and the higher Fs would probaly indicate less bottom in the pipe.
But if T/S vary as much as you say, then it is a crapshoot anyway.
The numbers from Bob's Peerless
Parameter Published Measured
fs 37.7 56.8
Vas 27.7 15.5
Qm 2.29 3.55
Qe .55 .495
Qts .44 .436
dave
Bylie said:
I wondered about the difference between the HDS and the CSX line as well. Both have composite sandwich cones, and very similar numbers. The magnet on the 182 HDS is slightly larger than on the CSX.
The HDS has an aluminum cast basket. The CSX a stamped steel frame. For this difference, the HDS costs 42% more.
I once read an article where the advantages for stamped steel frames over cast baskets were laid out by a manufacturer. While baskets stamped out with cheap soft metal does cause problems, the fact is that a well designed stamped basket can give you all the rigidity necessary. Moreover, the accuracy stamped affords in terms of drilling holes, etc., is greater than that possible with a cast design.
I once worked at a forging plant years ago. Anyone who has operated a pneuatically driven punch press and witnessed the immense forces necessary to form hard metal would never doubt that a stamped design holds the speaker components in place with absolutely no trouble at all.
Anyway, that is the difference between the CSX and the HDS line.
I see that you do not expect to run your sub during music. By not playing the sub, you do tend to muddy the mids.
Your Peerless Pipes will go down to 35 Hz, which is wonderful. On a chart. Even better is the fact that, according to the chart provided on the Peerless Pipe website, the Transmission Line seems to give the woofer substantial excursion relief up to and past 100 Hz.
But you are still trying to pump out bass with a 6 1/2 inch woofer, and simple physics says that the woofer must move a long way to produce that bass, even in a Transmission Line.
I did some math. The Peerless Pipe crosses over to the tweeter at 2500 Hz. Using the Modulation Distortion formula put forward by Paul Klipsh in the Journal Of The Audio Engineering Society, if you play a 50 Hz tone on your Peerless Pipe at the same time that you play at 2,000 Hz tone, at the SPL of 106 dB, you will have generated a Modulation Frequency whose amplitude is only 7.8 dB down from the music material! That is right-a distortion generated frequency not on the program material is almost as loud as the program material itself.
And this takes into account the excursion relief the Transmission Line affords. If this was a sealed design, the situation would be even worse.
This what you get for using a 6.5 inch woofer and trying to get deep bass output from it.
If you like Transmission Lines, here is a suggestion. Use your sub for music. build a Transmission Line with a 6.5 inch that goes down to 70 Hz. Have the subs cross in at 80 Hz.
If the Transmission Line affords elongated cone relief the way the Peerless Pipe did, your woofer will enjoy excursion relief close to 200 Hz, and you will have a cleaner sound all the way through the mids. The more the woofer has to move to play the bass, the higher the distortion in the midrange.
Focal has a Transmission Line project, I believe, that has a 70 Hz cutoff. Maybe you would like to adapt it to a Peerless driver.
It is not that the Peerless Pipe gives lousy bass using a 6.5" driver. In fact, it probably gives better bass than most any other enclosure using a 6.5 inch driver. But asking a 6.5 inch to go deep and also go high is really putting it under strain.
Here is a link to the discussion where the chart by Klipsch illustrates the Modulation Distortion a woofer picks up when it tries to cover too much of the audio spectrum.
http://www.diyaudio.com/forums/showthread.php?threadid=9818
Your Peerless Pipes will go down to 35 Hz, which is wonderful. On a chart. Even better is the fact that, according to the chart provided on the Peerless Pipe website, the Transmission Line seems to give the woofer substantial excursion relief up to and past 100 Hz.
But you are still trying to pump out bass with a 6 1/2 inch woofer, and simple physics says that the woofer must move a long way to produce that bass, even in a Transmission Line.
I did some math. The Peerless Pipe crosses over to the tweeter at 2500 Hz. Using the Modulation Distortion formula put forward by Paul Klipsh in the Journal Of The Audio Engineering Society, if you play a 50 Hz tone on your Peerless Pipe at the same time that you play at 2,000 Hz tone, at the SPL of 106 dB, you will have generated a Modulation Frequency whose amplitude is only 7.8 dB down from the music material! That is right-a distortion generated frequency not on the program material is almost as loud as the program material itself.
And this takes into account the excursion relief the Transmission Line affords. If this was a sealed design, the situation would be even worse.
This what you get for using a 6.5 inch woofer and trying to get deep bass output from it.
If you like Transmission Lines, here is a suggestion. Use your sub for music. build a Transmission Line with a 6.5 inch that goes down to 70 Hz. Have the subs cross in at 80 Hz.
If the Transmission Line affords elongated cone relief the way the Peerless Pipe did, your woofer will enjoy excursion relief close to 200 Hz, and you will have a cleaner sound all the way through the mids. The more the woofer has to move to play the bass, the higher the distortion in the midrange.
Focal has a Transmission Line project, I believe, that has a 70 Hz cutoff. Maybe you would like to adapt it to a Peerless driver.
It is not that the Peerless Pipe gives lousy bass using a 6.5" driver. In fact, it probably gives better bass than most any other enclosure using a 6.5 inch driver. But asking a 6.5 inch to go deep and also go high is really putting it under strain.
Here is a link to the discussion where the chart by Klipsch illustrates the Modulation Distortion a woofer picks up when it tries to cover too much of the audio spectrum.
http://www.diyaudio.com/forums/showthread.php?threadid=9818
This is the chart of the output from the Peerless Pipe as a whole, the driver and the port. The bold black line si the total output. The red line is the driver. As you can see, at frequencies below 125 Hz, the driver's putput does not equal the total output. That is the benefit from the Transmission Line.
If this were a sealed enclosure, the output of the red line and the bold black line would be the same, since in a closed box, the driver output IS the enclosure output. Not so in ported and Transmission Lines.
If the cutoff were 70 Hz, the Transmission Line would help the driver all the way up to 200 Hz.
If you have your heart set on the Peerless Pipe, by all means build it. This is your project. I just wanted to give you the facts on subs, cone excursion, Modulation Distortion, etc. before you begin.
The Peerless Pipe looks like a very very good way to build a 6 1/2 ihch two way speaker. I just wanted to let you know the limitations of a 6 1/2 inch two way speaker.
Good luck, whatever you decide. 🙂 🙂
If this were a sealed enclosure, the output of the red line and the bold black line would be the same, since in a closed box, the driver output IS the enclosure output. Not so in ported and Transmission Lines.
If the cutoff were 70 Hz, the Transmission Line would help the driver all the way up to 200 Hz.
If you have your heart set on the Peerless Pipe, by all means build it. This is your project. I just wanted to give you the facts on subs, cone excursion, Modulation Distortion, etc. before you begin.
The Peerless Pipe looks like a very very good way to build a 6 1/2 ihch two way speaker. I just wanted to let you know the limitations of a 6 1/2 inch two way speaker.
Good luck, whatever you decide. 🙂 🙂
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kelticwizard said:
Based on the concept of subs on the bottom of my left/rights and a small comment made in HiFi News* i am aiming for a system that plays music & HT with the subs being just the bass on the Large Mains. *This comment indicated that to generate small mains & to have a sub requires more post processing by the HT processor giving a greater chance to muck it up -- he suggested turning off the sub send & just let your large mains do the job.
If you have subs (i think you should always have 2) you should use them -- all the time.
dave
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