Neil Blanchard Designs MLTL4 Review: DIY Transmission Line Speakers Tested
United States of Analog | June 2, 2026
Original video title: These Speakers Hide an 8-Foot SECRET
🎙️ Early Video Analysis
United States of Analog – “These Speakers Hide an 8-Foot SECRET” (Transcript Analysis)
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What is this video about?
- The video is a review and explainer focused on the MLTL4 (Mass Loaded Transmission Line, Model 4) speakers from Neil Blanchard Designs, a DIY speaker kit
- The host, Bob, covers what transmission line speaker technology is, why it’s notable (especially for bass performance from small drivers), and why someone might want to build their own speakers
- Neil Blanchard himself is expected to appear later in the video to explain the engineering in more detail
- The video also briefly introduces different speaker enclosure types (sealed, ported, transmission line) as context
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Gear, products, or brands discussed:
- Neil Blanchard Designs MLTL4
- Mass Loaded Transmission Line speakers, DIY/build-your-own
- 4-inch woofer, one tweeter
- Tuned to 30 Hz despite the small driver
- Build cost estimated at $400–$700 depending on how much help is needed (e.g., crossover assembly)
- Bob has heard them at multiple audio shows, including a Dallas show where they were paired with Shelly Labs electronics
- Always performed well without subwoofers
- Klipsch Forte 4s
- Mentioned as Bob’s personal speakers upstairs
- Use a Tractrix port system and 15-inch passive radiators for bass extension
- Referenced as an example of a ported/passive radiator design, described as less controlled than transmission line
- Shelly Labs Electronics
- Partnered with Neil Blanchard at the Dallas audio show to drive the MLTL4 speakers
- The Horn Shop (Ed Schilling, somewhere in the Carolinas)
- Built horn speakers for Bob approximately 30 years ago
- Mentioned briefly as a segue, not fully discussed yet in this portion
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Host’s main opinions or takes so far:
- Transmission line technology extracts more bass from a small driver than sealed or ported designs, in a more controlled and tunable way — [00:02:30]
- Ported speakers release energy but in a “more crude way” compared to transmission line — [00:04:39]
- Neil Blanchard’s speakers have consistently performed well at audio shows — [00:02:15]
- Bob is enthusiastic about DIY speakers for the right person, though he admits he’s “not there yet” himself — [00:03:57]
- He openly admits he is not highly technical and will rely on Neil to explain the engineering — [00:01:02]
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Strong recommendations or warnings:
- Bob frames DIY speakers as a compelling option for those who want to save money ($400–$700 vs. commercial equivalents), challenge their skills, achieve performance unavailable in the commercial market, or create a unique custom piece — [00:03:10–00:03:57]
- Implicitly positions transmission line as superior to ported for controlled bass, though doesn’t dismiss other technologies outright
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Notable comparisons between products:
- Transmission line (MLTL4) vs. ported speakers: Transmission line described as more controlled and tunable; ported described as a “cruder” release of energy — [00:04:39]
- Transmission line vs. sealed: Sealed has “trapped energy” and potential unwanted resonance; ported and TL both address this differently — [00:04:11]
- Klipsch Forte 4 passive radiator system used as a real-world ported/passive radiator example for contrast — [00:04:53]
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Funny moments, strong opinions, or memorable quotes:
- *”Am I going to make a fool of myself? Most certainly. If you’re more technically oriented, you might want to stick around just to watch the train wreck.”* — [00:01:21] — Self-deprecating humor about his lack of technical expertise
- *”I’m music first, audiophile second, rocket scientist third.”* — [00:01:28] — Classic recurring self-description, used for a laugh
- *”Being an audiophile means always being in the classroom”* — [00:05:23] — Bob immediately wants this on a T-shirt and turns to look at his record collection for no apparent reason, which he acknowledges with amusement — [00:05:29]
- His description of sealed speakers having “trapped energy” followed by *”How’s that for non-technical talk?”* — [00:04:22] — Plays up his everyman persona
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3-Paragraph Summary
In this opening segment, host Bob introduces the MLTL4 speakers from Neil Blanchard Designs, a DIY mass loaded transmission line speaker that he has a pair of in for review. He sets up the video’s central question: does the “secret tunnel” — the transmission line inside these otherwise modest-looking bookshelf speakers — actually deliver on its promise of improved bass performance? Bob is upfront about his limited technical knowledge and promises that designer Neil Blanchard will appear later in the video to fill in the engineering gaps, framing himself humorously as more of an enthusiastic music lover than a technical expert.
Bob briefly walks through the three main speaker enclosure types — sealed, ported, and transmission line — to give viewers context. He describes sealed speakers as prone to trapped energy and resonance, ported speakers as a more common but somewhat crude solution, and transmission line as the most controlled and tunable approach to bass management. He uses his own Klipsch Forte 4s (with their Tractrix port and 15-inch passive radiators) as a real-world ported reference point, making clear he sees the MLTL4’s approach as more sophisticated, even from a small 4-inch driver tuned all the way down to 30 Hz.
The host also makes a case for DIY speaker building in general, outlining four motivations: saving money (the MLTL4 can be built for $400–$700), personal challenge, achieving performance beyond what’s commercially available, and the satisfaction of creating something unique — especially for woodworking enthusiasts. Bob admits DIY isn’t quite his world yet but is clearly enthusiastic about the MLTL4 based on his experience hearing Neil Blanchard’s speakers at multiple audio shows, where they consistently impressed without any subwoofer support.
⏱️ Mid-Video Analysis
Gear, Products, or Brands Discussed
- Folded horn speakers (general speaker type)
- Foztec driver (full-range single driver used in folded horn speakers)
- Transmission line speakers, specifically the MLTL4 model
- Dayton Audio drivers (used in the MLTL4, described as under $100 worth)
- Neil Blanchard Designs (DIY speaker design company, website: nbdesigns.org)
- Flat pack speaker kits offered by Neil Blanchard
Host’s Key Findings, Verdicts, or Opinions
- [00:05:58] Folded horn speakers offer “very detailed and very spot on imaging” due to the single full-range driver
- [00:06:07] Folded horn speakers are “super efficient”
- [00:06:19–00:06:29] Major downside of folded horns: they must be placed in corners to perform optimally, which isn’t practical for everyone
- [00:06:48–00:07:11] Transmission line design harnesses rear driver sound to produce deeper bass from a smaller, less expensive driver
- [00:07:11] “Smaller driver equals less money” — the TL design is framed as a cost-effective way to achieve deep bass
Listening Tests or Sound Quality Observations
- [00:05:58–00:06:07] Folded horn speakers noted for detailed, precise imaging attributed to the single full-range driver
- [00:06:48–00:06:57] The MLTL4 described as producing “a lot deeper bass out of this speaker for this size driver than you normally would”
Price/Value Assessments
- [00:08:07–00:08:14] Dayton Audio drivers in the MLTL4 cost “well under $100”
- Neil Blanchard sells plans, flat packs, and crossover assistance — positioned as an accessible, affordable DIY option
- The overall framing: transmission line design delivers outsized bass performance relative to driver size and cost
Comparisons to Other Gear Mentioned
- [00:05:42–00:06:29] Folded horn speakers compared to transmission line speakers in terms of placement flexibility and bass delivery
- [00:07:17–00:07:26] Ported speakers vs. transmission line: ported likened to “shouting into a cave,” while transmission line is “sending sound through a long winding cave” — TL characterized as superior for controlled, resonance-free bass
Audiophile Tips, Advice, or How-To Content
- [00:06:19–00:06:29] Folded horn speakers require corner placement to maximize bass performance — a key real-world limitation to consider
- [00:08:02–00:08:24] Neil Blanchard offers multiple entry points for DIYers:
- Plans for those who can cut their own wood
- Flat packs for those who cannot
- Crossover designs included
- Associated company available to build crossovers for those who don’t solder
- [00:10:16–00:10:23] Flat pack assembly requires: flat work surface, glue, and clamps (strap clamps recommended as easier and less expensive)
- [00:10:35–00:10:40] Suggestion to use local cabinet maker shops for cutting and building from plans, with option to use exotic hardwoods
- [00:09:05–00:09:19] Neil explains TL speakers as a “tuned column of air” — comparing the cabinet to a musical instrument like a saxophone, trombone, or organ pipe
Memorable Quotes or Strong Takes
- [00:07:17–00:07:26] *”Ported speakers are kind of like someone shouting into a cave. The transmission line speaker is like sending that sound through a long winding cave before it comes out the back.”*
- [00:07:11] *”Smaller driver equals less money.”*
- [00:08:51–00:08:59] Neil Blanchard: *”The simplest terms that I have heard is that they’re basically like a musical instrument. Think of a saxophone or a trombone or an organ pipe.”*
- [00:09:48–00:09:54] Neil on bass extension: *”The smallest of my speakers is a full range. It’s 40 Hertz, but then 30 down to 20 on all the other models.”* Host responds: *”That’s amazing. That’s amazing.”*
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Summary
This portion of the video begins with the host comparing two types of speaker designs — folded horn and transmission line — before zeroing in on the MLTL4 transmission line speaker from Neil Blanchard Designs. The host explains that while folded horn speakers (using a Foztec full-range driver) offer excellent imaging and efficiency, they require corner placement, which limits their practicality. Transmission line speakers, by contrast, harness the rear energy of the driver through a long, folded internal tunnel, producing unexpectedly deep bass from small, affordable drivers like those from Dayton Audio — all without the pressure buildup issues associated with ported designs.
The segment transitions into an interview with Neil Blanchard himself, who describes transmission line speakers using the analogy of a musical instrument — comparing the tuned air column inside the cabinet to a saxophone or organ pipe. Neil shares that his models range in sensitivity from 86 to 94 dB, and that his speaker designs can achieve bass extension down to 20 Hz despite using nominal 4- and 6-inch drivers. He emphasizes that the technology is rooted in designs dating back to the mid-1970s, supported by continually updated design software.
The host and Neil also walk through the DIY accessibility of these speakers. Neil offers plans, flat packs, crossover designs, and even connects buyers with a third-party crossover-building service for those uncomfortable with soldering. Local cabinet shops are suggested as a resource for exotic wood builds. The overall message is that high-performance transmission line speakers are achievable at a surprisingly low cost and with varying levels of DIY involvement, making them an attractive option for a wide range of audio enthusiasts.
🏁 Final Thoughts & Verdict
Gear, Products, and Brands Discussed
- MLTL-4s (Mass Loaded Transmission Line Model 4s) by Neil Blanchard Designs — the primary subject
- Leek AB amp (loaned by MoFi Distribution)
- McIntosh MA252 hybrid 100-watt amplifier (host’s personal unit)
- Technics (referred to as “techno deck”) from Michell — turntable
- AT (Audio-Technica) moving coil cartridge (brand new)
- Parasound XRM preamplifier
- iFi Zen phono preamplifier
- Dayton Audio — 4-inch driver used in the MLTL-4s
- Neil Blanchard Designs headphone amps with walnut and maple dovetail cases (mentioned briefly) [00:11:27–00:11:39]
Host’s Final Verdict / Conclusion
- The MLTL-4s genuinely reach 30 Hz, but the bass is not loud or chest-thumping by typical American audiophile standards [00:13:09–00:13:44]
- The speakers excel with jazz, singer-songwriter, acoustic, and classical music [00:13:52–00:14:15]
- The host found them revelatory for rethinking what good bass actually means — quality over quantity [00:14:54–00:15:08]
- He was impressed that a 4-inch Dayton Audio driver in a transmission line enclosure could produce such surprisingly good sound [00:15:58–00:16:06]
Final Recommendations
- Recommended for listeners who enjoy jazz, acoustic, singer-songwriter, and classical genres
- Not recommended as a standalone speaker for rock or bass-heavy music without a subwoofer — though the host notes adding a sub compromises some of the transmission line magic [00:14:19–00:14:41]
- Neil Blanchard’s other speaker designs are suggested for those who want more rock-and-roll capability [00:14:44–00:14:47]
- “Check these out. Build some in any way that you can.” [00:16:28–00:16:34]
Final Tips, Caveats, and Advice for Viewers
- Don’t expect chest-thumping bass — the low end is present but refined, not loud [00:13:37–00:13:44]
- Adding a subwoofer is possible but will muddy the sound and diminish the open-baffle feel [00:14:19–00:14:36]
- Placement experimentation is encouraged — host tried 12 to 18 inches from the front wall with good results; no super-precise placement required [00:16:06–00:16:28]
- Encourages viewers to reflect on what they actually want from bass — louder is not always better [00:14:54–00:15:08]
- Recommends listening to Sonny Rollins’ *Way Out West* as a showcase album for these speakers [00:16:34–00:16:40]
How the Video Wrapped Up
- The host thanked Neil Blanchard warmly, calling him “the mad scientist of speaker designs” and encouraging viewers to meet him at audio shows [00:12:04–00:12:26]
- He gave a personal listening summary covering amplifiers, sources, and musical genres used during his months-long evaluation [00:15:17–00:15:51]
- Closed with a lighthearted, self-deprecating tone, admitting exhaustion and joking about not knowing what he’s talking about [00:16:53–00:17:04]
- Standard YouTube outro with a recommendation to watch another video [00:17:19–00:17:29]
Memorable Closing Quotes / Strong Final Opinions
- *”Louder is not always better when it comes to bass.”* [00:14:54]
- *”Kick back with a glass of wine and listen to the late Sonny Rollins like Way Out West… deep bass, but not bass that’s going to shatter your wine glass.”* [00:16:34–00:16:53]
- *”It’s almost hard to believe”* — referring to what the 4-inch Dayton driver achieves in a transmission line package [00:16:04–00:16:06]
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Summary
In the final portion of this video, the host wraps up his extended evaluation of the Neil Blanchard Designs MLTL-4 mass loaded transmission line speakers. He warmly praises Neil as a designer and person, calling him “the mad scientist of speaker designs” and encouraging viewers to seek him out at audio shows. The tone is genuine and appreciative, though the host is quick to clarify that his praise isn’t an attempt to keep the speakers — they have to go back.
The host then delivers his honest sonic assessment. While he confirms the speakers reach 30 Hz, he notes that the bass, though extended and accurate, is not the loud, chest-thumping kind that many American audiophiles expect. He found the speakers most rewarding with jazz, acoustic, singer-songwriter, and classical music, and says the experience genuinely changed how he thinks about bass quality versus bass quantity. He cautions that adding a subwoofer is possible but will compromise the transmission line’s coherence and open-baffle character.
The host shares his full test setup — including the McIntosh MA252, Leek AB amp, Michell turntable with an AT moving coil, Parasound XRM preamp, and iFi Zen phono stage — and advises viewers to experiment with placement. He closes by recommending *Way Out West* by Sonny Rollins as an ideal album to showcase what these speakers do best, and signs off with his trademark casual humor, admitting exhaustion and self-deprecatingly questioning his own expertise before handing off to a YouTube-recommended video.
Analysis generated from archived transcripts. Channel: United States of Analog — hi-fi gear reviews, vinyl, and audiophile culture.
