[joessportster]

Curious what folks might think, I happen to have 2 pair of the Lii F-15 drivers I currently use 1 pair over top of Eminence alpha 15 and love the sound, Now I am just wondering if I would gain anything by adding the second pair oof F-15...............Several Options for configuration I like the idea of the PAP design and putting the alpha in the middle but that would be a very TALL BAFFLE

Thoughts ?

Thanks Joe

[joessportster]

Heres a pic of current setup

[joessportster]

The baffles are 18" square then stacked and tilted back around 7 degree, Amps on the F-15 are a toss up between 45, 300b, Tom Tutay MK IV, QS Horn Monos, or I could even throw somme OOoommph at her with the VRD stereo amp...................Right now I am really enjoying the Tom Tutay Modded Dynaco MK IV Mono Blocks  (RIP TOM)

[planet10]

More level potential (+3dB), but, particularily with such a huge FR will be a whole lot of combing starting above the frequency equivalent to the centre-to-centre of the 2 drivers. Say 16” minimum. That is above ≈210 Hz. It gets worse as you go up in frequency.

Combing is harder to hear than it may seem in the image but in your case it will be of such a magnatude that it will be fairly oibvious.



dave

[Woodsage]

What are you trying to gain by adding another F15?

The PAP’s use two identical mid woofers in a 2.5 way configuration. IMO this gives a fuller mid-range and a solid bass foundation, at least within their frequency range.

Given the limited frequency extension of the F15 I think I would add a tweeter of some sort before I added another 15” full range.

I went with the Lii 10” Silver EVO because of the balance between top end extension and low end response. Below I use two active W15’s which can be run fairly high (if need be) and have good response to 28Hz.

I considered putting the 10” in the center like PAP but that seems too low to me. I haven’t finalized my baffles yet so may still go that route.

[joessportster]

I have no particular gains in mind, Its more curiosity I have the drivers and it wont cost anything to try it. I had the Crystal 10's, the Fast 10's and the silver 10's of the 3 the silver was best but cannot match the fullness of the F-15........

[FullRangeMan]

Any advantage to Multiple Full Range drivers per side
The only vantage I see is just in case you like Line Array kind
of sound, you could add eight 1Ω FR drivers (16 for a small
tube amp) is need 1Ω drivers for a serial connection, avoid
serial-parallel connection, they have a wild behavior at high
SPL as I eventually came to discover with just four drivers.
Small FR drivers are suited IMO, max 8 inches size.
Here a Paul Hines LA with 8 Visaton B200.

[Woodsage]

I have no particular gains in mind, Its more curiosity I have the drivers and it wont cost anything to try it. I had the Crystal 10's, the Fast 10's and the silver 10's of the 3 the silver was best but cannot match the fullness of the F-15........

Agreed, large format drivers have a body to them that is hard to beat. The only driver I would add multiples of would be  bass drivers to get more bass output and dynamics from an OB.

Here is a pair I built using 3 PAP 15” drivers back when they still sold drivers. The top and bottom drivers are active bass and the middle one was a mid-range running from about 800 Hz down to its natural roll off point. So it’s a two way with active bass.

Unlike Sir-Mix-A-Lot I don’t like big butts but I do like big speakers, I just don’t have room for them anymore.

Any advantage to Multiple Full Range drivers per side
The only vantage I see is just in case you like Line Array kind
of sound, you could add eight 1Ω FR drivers (16 for a small
tube amp) is need 1Ω drivers for a serial connection, avoid
serial-parallel connection, they have a wild behavior at high
SPL as I eventually came to discover with just four drivers.
Small FR drivers are suited IMO, max 8 inches size.
Here a Paul Hines LA with 8 Visaton B200.

They could be wired with groups in parallel and those groups wired in series to achieve a realistic 4-8 ohm load. I’ve built a couple line arrays (not with full range drivers) and they are really fun speakers. The scale and dynamics are hard to beat.

[Jon L]

Where did you get that waveguide for (?) Beyma TPL-150 (200).

I'm working with TPL-150H right now, and that's definitely not the Beyma waveguide.
Also, you are using the stock faceplate on the back side of the AMT?  Clever.

[Woodsage]

Where did you get that waveguide for (?) Beyma TPL-150 (200).

I'm working with TPL-150H right now, and that's definitely not the Beyma waveguide.
Also, you are using the stock faceplate on the back side of the AMT?  Clever.

That is not a Beyma AMT. If you look at the second picture in my post above you will see a mahogany baffle in the background that IS using a Beyma TPL 150 without a horn.

The AMT in the tall speakers was / is made by Jack Smiley and goes much lower than the Beyma (as low as 500 Hz) it is also larger and more robust than the Beyma. The wave guide is also from Jack Smiley and is cast resin.

Jack's AMT and wave guide were used by Hawthorne Audio in their reference series speakers back around ten years ago.

[FullRangeMan]

They could be wired with groups in parallel and those groups wired in series to achieve a realistic 4-8 ohm load. I’ve built a couple line arrays (not with full range drivers) and they are really fun speakers. The scale and dynamics are hard to beat.

I already alerted about this option.

[Woodsage]

I already alerted about this option.

Oops, sorry I missed that FullRangeMan!

@joessportster

Sorry this thread may have been taken a bit off track…. but I found this video really interesting and somewhat relative to your original question. Your drivers are much larger than the ones in the video but it’s interesting (at least to me) none-the-less. The thing to do is to throw that second F15 into the mix and let us know what you find out!

https://www.youtube.com/watch?v=ytII-BY3EAo

[joessportster]

Not Off track at all, I am happy to see the differeent ideas and builds, LOVE those Mahogany Baffles...............I will be experimenting next week and will try and update here in a timely manner

I appreciate all the info / responses

[FullRangeMan]

With two F15 pairs could be possible made a boxed Bipolar Bass Reflex enclosure according the Lii Audio plans in double (two times).

[Jon L]

Jack's AMT and wave guide were used by Hawthorne Audio in their reference series speakers back around ten years ago.

Good old hawthorne Audio! They were ahead of their time.

I added the Beyma horns to TPL-150 but found horns added a significant bump below about 7kHz, making some recordings with strong content between about 1-7kHz a bit too forward.  I kind of prefer the TPL-150 without the horns, just sitting on top without a baffle even.  However, I AM trying to cross at 1kHz with 18dB slope, so would adding just flat baffles like your mahogony speaker extend the bottom end of TPL-150 enough without unusual bumps?  TIA.

[Woodsage]

Good old hawthorne Audio! They were ahead of their time.

I added the Beyma horns to TPL-150 but found horns added a significant bump below about 7kHz, making some recordings with strong content between about 1-7kHz a bit too forward.  I kind of prefer the TPL-150 without the horns, just sitting on top without a baffle even.  However, I AM trying to cross at 1kHz with 18dB slope, so would adding just flat baffles like your mahogony speaker extend the bottom end of TPL-150 enough without unusual bumps?  TIA.

Yes, I consider Hawthorne Audio to have been an OB pioneer.

Those are nice looking baffles, what are the woofers and what size are they?

Although the TPL 150's are often used down to 1000 Hz I never had any luck with them down that low and ended up crossing them over higher, between 1,600-1,800 Hz, so more like a tweeter than a wide band driver. I thought they sounded better that way and they are a nice sounding driver within their limitations.

I doubt that baffle reinforcement plays a huge role in low end extension with the TPL 150 but it might help with the bump you are experiencing. I don't think the horn is needed in most home listening situations for the reason you mention above although it may help in a no baffle setup like you have there. I think if the horn was more of a wave guide and larger it would yield better results and keep the response smoother as the volume increases.

All that being said I don't have a ton of direct experience with the Beyma TPL 150 so take it all with a grain of salt.

Sorry I couldn't help much but keep us posted if you change things around.

[Jon L]

Those are nice looking baffles, what are the woofers and what size are they?

Although the TPL 150's are often used down to 1000 Hz I never had any luck with them down that low and ended up crossing them over higher, between 1,600-1,800 Hz

The woofers are 8" Seas, and they sound great even well past 1kHz.  Even without the horns, I was doing fine with TPL-150 at 1kHz, likely because of 18dB slope via outboard active crossover and the fact I am playing at mostly 70-78dB loudness at listening position, so not much stress on drivers.  The addictive thing about 150H is while some borderline recordings sound more borderline, truly great, balanced recordings sound AMAZING with added life and presence.
I know many people DSP/EQ their way around these issues, but my ears must be extra sensitive to DSP/EQ, which is very noticeable to me when they involve midrange/treble.   Decisions..

[Jon L]

duplicate

[FullRangeMan]

I know many people DSP/EQ their way around these issues, but my ears must be extra sensitive to DSP/EQ, which is very noticeable to me when they involve midrange/treble.   Decisions..

+1. Submit to processing the entire musical range of a recording just to boost the bass isnt very smart.

[joessportster]

+2, everytime I try digital processing I get fatigued quickly and the sound quality seems to get dry