Best midrange to pair with Beyma TPL-150

Hey Henry.



Considering your experience with the TPL and with speakers in general, which off-the-shelf midrange/s would you recommend for the TPL-150H?



Thank you!



It depends on your application.

If you only need 200-2khz, then any good performance 8" should be fine.

Often people hung up on which model, brand or shape.

The crossover filter plays more part than any other equation, as these days you can find so many good to great drivers, while the latter is getting more and more.



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It depends on your application.

If you only need 200-2khz, then any good performance 8" should be fine.

Often people hung up on which model, brand or shape.

The crossover filter plays more part than any other equation, as these days you can find so many good to great drivers, while the latter is getting more and more.

More than fair enough!!

My application:
  • 4-way system with active digital linear phase crossovers, time aligned, digital room correction applied too. Steep xo slopes.
  • Attempting to get away with SETs driving midrange and treble. Moreover, looking at 45-based SET. So 2W per channel at full steam, but I'm designing as if I had 1W per channel tops so to keep SET distortion low.
  • TPL-150H are about 103-104dB at 2.83V, so would love to have a midrange that was 100dB sensitivity.
  • Mibass are dual 10" driven by class D. These could easily be xo at 500Hz, but I'd rather do so lower.
  • Midrange would tentatively be 350-2000Hz.
Let's take the 5 drivers in the attachment, in 8 and 10". I have stretched the response curves from the manufacturers so all show in about the same scale, and I've added the intended range in the graphs. I also added some metrics and ratios.


Here I share my thinking looking to get feedback and thus learn:

I understand low Le is better for a midrange, so the 10NDA610 looks best from this point of view and has the highest sensitivity rating. My reading of that raising response is I will need to trim down sensitivity to the lower end of the range. So the sensitivity I will end up with will be significantly smaller. Plus a 10" will have a harder time around 2kHz, dispersion-wise.

The Audax starts getting a rough response around 2kHz and so is impedance, suggesting distortion likely rising.

The 8PE21, 8PR155 and 10PR410 have a relatively flat response in the intended range. The 10PR410 is noted by the manufacturer to be recommended up to 2kHz, so makes me wonder.

I tend to conclude 8PE21 and 8PR155 would be my best choices. One with slightly higher sensitivity and much stronger motor, the other with lower Le.

And then I throw in the fullrangers like Lowher and Tang Band, with their VERY low Le and higher impedance, and there I go again :D

What do you think?
 

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More than fair enough!!

My application:
  • 4-way system with active digital linear phase crossovers, time aligned, digital room correction applied too. Steep xo slopes.
  • Attempting to get away with SETs driving midrange and treble. Moreover, looking at 45-based SET. So 2W per channel at full steam, but I'm designing as if I had 1W per channel tops so to keep SET distortion low.
  • TPL-150H are about 103-104dB at 2.83V, so would love to have a midrange that was 100dB sensitivity.
  • Mibass are dual 10" driven by class D. These could easily be xo at 500Hz, but I'd rather do so lower.
  • Midrange would tentatively be 350-2000Hz.
Let's take the 5 drivers in the attachment, in 8 and 10". I have stretched the response curves from the manufacturers so all show in about the same scale, and I've added the intended range in the graphs. I also added some metrics and ratios.


Here I share my thinking looking to get feedback and thus learn:

I understand low Le is better for a midrange, so the 10NDA610 looks best from this point of view and has the highest sensitivity rating. My reading of that raising response is I will need to trim down sensitivity to the lower end of the range. So the sensitivity I will end up with will be significantly smaller. Plus a 10" will have a harder time around 2kHz, dispersion-wise.

The Audax starts getting a rough response around 2kHz and so is impedance, suggesting distortion likely rising.

The 8PE21, 8PR155 and 10PR410 have a relatively flat response in the intended range. The 10PR410 is noted by the manufacturer to be recommended up to 2kHz, so makes me wonder.

I tend to conclude 8PE21 and 8PR155 would be my best choices. One with slightly higher sensitivity and much stronger motor, the other with lower Le.

And then I throw in the fullrangers like Lowher and Tang Band, with their VERY low Le and higher impedance, and there I go again :D

What do you think?

I think your really stuck on this '45 SET business. Only works well driving a compression driver, despite all the marketing and "guru" b.s. that is out there.
If you want to use a SE DHT, than I suggest a 300B based amplifier. I did a research test on power consumption of my 4-way active system, because I am currently using a Class A, S.E. amp built on germanium transistors, no feedback. With my 105 db/watt sensitive horn loaded TB 1772's, the maximum draw was 3.2 watts when the SPL averages were 95db at the listening position, which is 12 feet away from the horn mouth. Remember, it's the dynamics of the musical content that you DO NOT wish to compress. This ensures being able to enjoy the emotional expression that is realized best in a live acoustical instrument performance.
 
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Looks like you have qualified the midranges after all [emoji16].

I agree with Scott L, 2w is not enough, especially crucial bandwidth 100-500hz.

8PR155 is a great driver.


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Hello Henry,
You bring up an excellent point that deserves further discussion.
The octave between 250-500Hz is where the center of all acoustic power is concentrated. In other words, this is an extremely dense area for music information. This is also why some guys like to use mid-bass horns, because of the effortlessness by which this frequency area can be reproduced. There is more than just "one perfect way" to do things, however there also exists some rules, or laws of physics, that we can use as a guide. In my own personal experience, I have obtained the very best results by keeping the mid-range intact upon itself. It could easily be argued that mid range starts lower than where I do, but for me it starts at 250Hz. Horn-loaded mid-range, with a high focus and directivity factor make for very enjoyable music. Getting back to the "test" I did, the following results were revealed: using a "peak power hold" meter, I was able to determine the maximum power draw form each of my "4-ways", with 95db averages at the listening position. It was determined that this was VERY LOUD, and seldom do i play it that loud, but I wanted results of an extreme situation. 60/250/8K Hz are the crossover points. Sub: 2 watts. Mid-bass: 2 watts. Mid-range: 3.2 watts. Tweeter: 300 milliwatts.
 
More than fair enough!!

My application:
  • 4-way system with active digital linear phase crossovers, time aligned, digital room correction applied too. Steep xo slopes.
  • Attempting to get away with SETs driving midrange and treble. Moreover, looking at 45-based SET. So 2W per channel at full steam, but I'm designing as if I had 1W per channel tops so to keep SET distortion low.
  • TPL-150H are about 103-104dB at 2.83V, so would love to have a midrange that was 100dB sensitivity.
  • Mibass are dual 10" driven by class D. These could easily be xo at 500Hz, but I'd rather do so lower.
  • Midrange would tentatively be 350-2000Hz.
Let's take the 5 drivers in the attachment, in 8 and 10". I have stretched the response curves from the manufacturers so all show in about the same scale, and I've added the intended range in the graphs. I also added some metrics and ratios.


Here I share my thinking looking to get feedback and thus learn:

I understand low Le is better for a midrange, so the 10NDA610 looks best from this point of view and has the highest sensitivity rating. My reading of that raising response is I will need to trim down sensitivity to the lower end of the range. So the sensitivity I will end up with will be significantly smaller. Plus a 10" will have a harder time around 2kHz, dispersion-wise.

The Audax starts getting a rough response around 2kHz and so is impedance, suggesting distortion likely rising.

The 8PE21, 8PR155 and 10PR410 have a relatively flat response in the intended range. The 10PR410 is noted by the manufacturer to be recommended up to 2kHz, so makes me wonder.

I tend to conclude 8PE21 and 8PR155 would be my best choices. One with slightly higher sensitivity and much stronger motor, the other with lower Le.

And then I throw in the fullrangers like Lowher and Tang Band, with their VERY low Le and higher impedance, and there I go again :D

What do you think?
4 way for domestic system
oh gosh
 
Looks like you have qualified the midranges after all [emoji16].

I agree with Scott L, 2w is not enough, especially crucial bandwidth 100-500hz.

8PR155 is a great driver.


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Henry and Scott L,

Thanks for the comments. They did make me pause and reconsider, and revisit. One thing I had decided back when I started was to go with higher impedance drivers (my current Faital M5N12 is 12ohm), and somehow I drifted away and was now considering 8ohm drivers.

Coincident Speakers is a company that knows SETs pretty well and their speakers are raved about and obviously good fit for SET amps. To take an example, their Super Victory II speaker is noted as "Their high sensitivity, smooth 10 ohm impedance modulus, simple first order crossover, phase coherency both acoustically and electrically all ensure that SET 300B, 211 or even 2A3 tube amplifiers will mate optimally", while they are rated at 92.5 dB sensitivity. Let alone the 4W 2A3, but even the 8W 300B would generally be considered too little for a 92.5dB sensitivity speaker. In my mind the key is the high impedance.
Moving a step up in their speaker line-up, the Total Victory V is rated at 95dB sensitivity and 10ohm impedance, yet also a SET friendly speaker.

Looking at DIY world: Lowther PM5A, Yamamoto A-08S, New Baffle Design & Impressions
Here's an experienced DIYer using a 45 SET with a Lowther PM5A rated at 96dB sensitivity and 15ohm. He's running the PM5 from 250Hz up with a 45 SET. Again, 2W into 96dB wouldn't be considered enough.

In my mind this shows sensitivity shouldn't be used in isolation to conclude how much power is enough to drive a speaker, but also impedance should be considered. For a given power being delivered, doubling the impedance will halve the current needed to achieve said power.


Additionally there is the active nature of the setup. Obviously it's not the same to attempt to use a 300B 8W for 20Hz to 20kHz than breaking this down into 4 channels. Scott's measurements show this, and his midrange is rated at 8ohm and reaches to about 5ohm minimum. If 350Hz is generally considered as the mid point for power consumption, then I'm looking at powering one half with two 2W amps (one for tweeter and the other for midrange). Scott's midrange starts lower and ends around 6kHz if I recall correctly, so wider range than my intent hence higher power consumption.


My takeaway is a reinforced attention to higher impedance drivers for the midrange. Will revisit my options. And after I get my first 45 SET test if it indeed has enough power or I should change plans for the midrange amp.

Cheers!
 
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A comedy of errors

Henry and Scott L,

Thanks for the comments. They did make me pause and reconsider, and revisit. One thing I had decided back when I started was to go with higher impedance drivers (my current Faital M5N12 is 12ohm), and somehow I drifted away and was now considering 8ohm drivers.

Coincident Speakers is a company that knows SETs pretty well and their speakers are raved about and obviously good fit for SET amps. To take an example, their Super Victory II speaker is noted as "Their high sensitivity, smooth 10 ohm impedance modulus, simple first order crossover, phase coherency both acoustically and electrically all ensure that SET 300B, 211 or even 2A3 tube amplifiers will mate optimally", while they are rated at 92.5 dB sensitivity. Let alone the 4W 2A3, but even the 8W 300B would generally be considered too little for a 92.5dB sensitivity speaker. In my mind the key is the high impedance.
Moving a step up in their speaker line-up, the Total Victory V is rated at 95dB sensitivity and 10ohm impedance, yet also a SET friendly speaker.

Looking at DIY world: Lowther PM5A, Yamamoto A-08S, New Baffle Design & Impressions
Here's an experienced DIYer using a 45 SET with a Lowther PM5A rated at 96dB sensitivity and 15ohm. He's running the PM5 from 250Hz up with a 45 SET. Again, 2W into 96dB wouldn't be considered enough.

In my mind this shows sensitivity shouldn't be used in isolation to conclude how much power is enough to drive a speaker, but also impedance should be considered. For a given power being delivered, doubling the impedance will halve the current needed to achieve said power.


Additionally there is the active nature of the setup. Obviously it's not the same to attempt to use a 300B 8W for 20Hz to 20kHz than breaking this down into 4 channels. Scott's measurements show this, and his midrange is rated at 8ohm and reaches to about 5ohm minimum. If 350Hz is generally considered as the mid point for power consumption, then I'm looking at powering one half with two 2W amps (one for tweeter and the other for midrange). Scott's midrange starts lower and ends around 6kHz if I recall correctly, so wider range than my intent hence higher power consumption.


My takeaway is a reinforced attention to higher impedance drivers for the midrange. Will revisit my options. And after I get my first 45 SET test if it indeed has enough power or I should change plans for the midrange amp.

Cheers!

Yes, you can always use the '45 SET for the tweeters. Guess you will have to find out for yourself. That's actually the best approach. It's wise not to believe me, or anyone else for that matter, on these discussion forums. I read through the first page of the AC post by Richard, and the follow ups. If you look at exactly how he decides it "sounds so good", based on the room set up and the approach, I would not trust the way he hears things. What a disaster.
This is probably the very best example I have seen of a novice following all these rules of mysticism. Open baffle, 6 db/oct crossovers, etc. etc.

I have included the phase and impedance measurement of my mid-range section. I don't see the dip down to 5 ohms. I have no idea where you got that (?) CHECK THAT. The file is too big to upload here. I took a picture from the screen instead. Probably can't see much from it. Darn
 

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Yes, you can always use the '45 SET for the tweeters. Guess you will have to find out for yourself. That's actually the best approach. It's wise not to believe me, or anyone else for that matter, on these discussion forums. I read through the first page of the AC post by Richard, and the follow ups. If you look at exactly how he decides it "sounds so good", based on the room set up and the approach, I would not trust the way he hears things. What a disaster.
This is probably the very best example I have seen of a novice following all these rules of mysticism. Open baffle, 6 db/oct crossovers, etc. etc.

I have included the phase and impedance measurement of my mid-range section. I don't see the dip down to 5 ohms. I have no idea where you got that (?) CHECK THAT. The file is too big to upload here. I took a picture from the screen instead. Probably can't see much from it. Darn

You are right Scott: your driver's impedance doesn't fall as much as I had seen on the manufacturer's graph http://www.tb-speaker.com/uploads/files/c437a19a817c805066d11d113e29b0a5.pdf

Interesting driver!
 
lI1J65j.jpg

i dont know b&w fst´s specs but here is no eq, no xo and same amp gain levels comparison

after eq i have to pad fst 5db down

FST is a great driver. I have them in my B&W and love them. They are rated at 94dB sensitivity, though, and low impedance. Impedance is low, but very flat. I remember someone measured this online. Excellent driver, but not for my application.
 
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yea just thinkin what sensitivity really is on those, there are 4-5 different fst´s versions
measured that horn would not add any gain to 2k and tpl is 100db at 10k

i still have to -5 db fst

reason have to be that amp plays louder 3.4ohm speaker that it does 5.9ohm one?
 
On the graph supplied by TB,
the db is scale is on the left, the impedance scale is on the right.

Since the very first time I heard this driver, I knew I wanted it. It just sounded "right". (and "right" is a personal subjective opinion)

Indeed. I must have looked at the wrong axis. So minimum impedance is about 8ohm.

Have you heard Lowthers? How do they sound different from your midrange?
 
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Indeed. I must have looked at the wrong axis. So minimum impedance is about 8ohm.

Have you heard Lowthers? How do they sound different from your midrange?

Sadly enough, I have only heard one pair of Lowther's in my life time. It was back in the year 2004, in Austin Texas, and the sound quality was SUPERB.
If memory serves correct, they were DX-2's and mounted in ORIS 150's.

That, my friend, was a life altering audio experience and forever influenced what I wanted for myself.

It's been a long number of years ago, so I can't really compare. Both his and mine are superb. Tang Band gets a bad rap because they don't cost enough money for the snobs. AER and Voxativ no doubt, rank even higher than
superb.
I did hear some Voxativ at Axpona,Atlanta 2011, and have to say they were sublime (which ranks higher than superb) :)