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Every hearing conservation vendor will tell you their model is better. Mobile van providers emphasize no equipment investment and turnkey scheduling. In-house digital programs emphasize flexibility and data continuity. Neither pitch gives you the analytical framework to make the decision for your specific operation. This guide does.
Soundtrace provides in-house digital audiometric testing that operates without a sound booth — using validated ambient noise monitoring and RadioEar DD65V2 circumaural headsets to deliver ANSI S3.1-compliant testing at your facility, on your schedule, integrated with real-time noise monitoring and professional supervisor oversight.
Mobile van audiometry: A vendor operates a vehicle-mounted sound booth that visits the employer’s facility once or twice per year. The van includes calibrated audiometric equipment, often a certified OHC technician, and a sound-attenuating environment built into the vehicle. Testing is conducted during the visit; audiogram results are typically reviewed by a remote audiologist or physician after the visit. Results and records are held in the vendor’s system and accessed via a portal.
In-house audiometric testing (digital/boothless): The employer conducts testing at their own facility using validated audiometric equipment that doesn’t require a traditional sound booth. Testing can be integrated into occupational health appointments, conducted by trained internal staff or a visiting OHC, and performed on a flexible schedule year-round. Professional supervisor review is conducted remotely by the program’s audiologist or physician. All records are in the employer’s digital system.
A third model — employer-owned sound booth and equipment — exists primarily at large facilities with sufficient testing volume to justify capital investment. This guide focuses on the mobile van vs. in-house digital comparison, which is the practical choice for most employers.
▶ Bottom line: The core difference between the models is scheduling control. Mobile van programs operate on the vendor’s calendar; in-house programs operate on the employer’s. Everything else — cost, compliance risk, data quality — flows from that distinction.
OSHA requires annual audiometric testing. “Annual” means within 12 months of the previous test, not within a calendar year. A mobile van that visits once per year creates a compressed testing window — all enrolled employees must be tested during a 1–3 day visit.
The practical compliance risk this creates:
In-house programs can test employees on any schedule: new hires within the required baseline window, STS retests within 30 days, and annual testing distributed throughout the year on an enrollment-anniversary basis rather than a single compressed visit.
▶ Bottom line: Mobile van programs pass compliance on paper when everything goes perfectly. When a shift is missed, an employee is absent, or an STS retest is needed, the annual-visit model creates compliance gaps that in-house programs handle routinely.
One of the most significant technical differentiators between mobile van and in-house digital programs is how ambient noise is managed during testing. Both models must produce valid audiograms — which means the test environment noise must not exceed levels that could mask the test tones and artificially elevate measured thresholds.
Mobile vans use a physical sound booth built into the vehicle — a purpose-built, acoustically treated enclosure that provides consistent ambient noise attenuation. This approach is well-established and straightforward.
Modern in-house digital programs use a different approach: validated high-attenuation circumaural headsets with real-time ambient noise monitoring. Soundtrace uses the RadioEar DD65V2 circumaural headset with documented acoustic attenuation specifications. Before each test, the system measures the actual ambient noise level in the test environment and compares it against ANSI S3.1-1999 masking criteria for the specific headset. If ambient noise is too high, the test is paused until conditions are acceptable.
This event-level validation — confirming noise adequacy at the time of each threshold response rather than assuming a static environment — provides rigorous assurance that audiograms are not contaminated by ambient noise, even in facility environments outside a traditional booth.
▶ Bottom line: Both models can produce valid audiograms. The boothless digital approach requires validated headset attenuation data and real-time ambient monitoring; the mobile van approach uses a physical enclosure. Neither is inherently superior — what matters is that the ambient noise standard is documented and consistently applied.
Direct per-test cost comparisons between mobile van and in-house digital programs often favor the van for very small programs and the in-house model for larger ones. But direct per-test cost is only part of the picture:
| Cost Element | Mobile Van | In-House Digital |
|---|---|---|
| Per-test direct cost | Higher at small volume; decreases at scale | Generally lower per-test at most volumes |
| Missed employee make-up visits | Additional cost per make-up visit | No additional cost; test when employee is available |
| STS retest logistics | Additional van visit or outside clinic cost | Included; conducted on-site within 30 days |
| New hire baseline scheduling | Often requires make-up visit or clinic | Conducted on enrollment; no additional cost |
| Equipment ownership | None | Equipment provided/maintained by vendor |
| Administrative burden | Annual scheduling coordination, rounding up employees | Distributed throughout year; integrates with onboarding |
| Compliance remediation | Higher risk of citations and associated costs | Lower compliance gap risk |
For facilities above approximately 50–100 enrolled employees, in-house digital programs are typically more cost-effective when total program cost (including make-up visits, STS retests, new hire baselines, and administrative time) is considered. Below 50 employees, the comparison is closer and depends heavily on the specific van provider’s pricing structure.
▶ Bottom line: Per-test cost comparisons systematically undercount the true cost of mobile van programs by excluding make-up visit logistics, STS retest costs, and the compliance risk premium of annual-visit models. Total program cost is the correct comparison metric.
One of the less-discussed but practically significant differences between the models is data continuity when vendors change. Mobile van programs store audiometric records in the vendor’s proprietary system. When an employer switches vendors — due to pricing, service quality, or vendor consolidation — historical audiograms may be difficult to transfer in a usable format, creating baseline continuity problems.
For OSHA compliance, new baselines may need to be established if historical records can’t be imported — which means legitimate hearing changes that should be detected as STSs against the original baseline may be missed for years.
In-house digital programs where the employer controls their data mitigate this risk. Regardless of what changes at the vendor level, the employer maintains ownership and access to complete audiometric histories for all employees.
▶ Bottom line: Ask any hearing conservation vendor: if we end our relationship tomorrow, can we export our complete audiometric records in a standard format? The answer tells you a great deal about the actual data portability of the program.
The most clinically significant difference between mobile van and in-house digital programs is STS management. Under 1910.95(g)(7)–(8), an STS requires: employee notification within 21 days, hearing protection refitting, professional supervisor review, optional retest within 30 days, and OSHA 300 recordability determination.
In a mobile van program, the STS is typically identified after the van visit when results are reviewed by the remote professional supervisor — often weeks after the test. The 21-day notification clock starts from when the employer receives the reviewed results. The 30-day retest window may already be partially consumed. Scheduling a retest requires coordinating another visit or clinic appointment. The entire follow-up workflow is compressed and logistically complex.
In an in-house digital program, the professional supervisor can review audiograms continuously or at regular intervals — not just once per year. STS cases can be flagged, reviewed, and acted on within days of the test. The 30-day retest window is easily met. The follow-up workflow can be automated and documented within the same system.
Mobile van programs are better suited for: very small programs (under 25–30 employees) where in-house program overhead doesn’t justify the setup; single-shift operations with high scheduling predictability and low absenteeism; and facilities that lack a suitable in-house test environment and have constrained quiet spaces.
In-house digital programs are better suited for: multi-shift operations where scheduling a single annual visit is complex; facilities with significant employee turnover requiring frequent baseline testing for new hires; operations with elevated STS rates where timely retests and follow-up are important; multi-site operations where a consistent program across all sites is operationally valuable; and any employer whose OSHA 300 hearing loss rate or past inspection history makes documentation quality a priority.
Ask these questions to guide the decision:
Soundtrace delivers OSHA-compliant audiometric testing without a sound booth, on your schedule, with continuous access to your audiometric data and same-day STS follow-up capability — not once a year when the van shows up.
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