Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.36 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.60 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
54 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.002
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.10 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
3.21 s
Page Load Progression
FPage Weight BudgetAction14.8 MB transferred, 96 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS BundlesAction42 scripts, 718 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.sennheiser.com/_next/static/chunks/0xyynutob2tcl.js | 365 KB | 343 KB (95%) | ✓ | 3rd |
| https://www.sennheiser.com/_next/static/chunks/0rt4v1t9arkri.js | 130 KB | 129 KB (99%) | ✓ | 3rd |
| https://app.usercentrics.eu/browser-ui/3.99.0/index.module.js | 121 KB | 53 KB (44%) | ✓ | 3rd |
| https://cdn.optimizely.com/js/4875027175178240.js | 76 KB | 34 KB (45%) | ✓ | 3rd |
| https://www.sennheiser.com/_next/static/chunks/0r4m3wnd5ngs1.js | 52 KB | 34 KB (65%) | ✓ | 3rd |
| https://www.sennheiser.com/_next/static/chunks/0xxk445_iw963.js | 36 KB | 29 KB (81%) | ✓ | 3rd |
| https://app.usercentrics.eu/browser-ui/3.99.0/VirtualServiceItem-e4cab338.js | 49 KB | 26 KB (54%) | ✓ | 3rd |
| https://www.sennheiser.com/_next/static/chunks/16tmcv-qfnfy5.js | 68 KB | 26 KB (39%) | ✓ | 3rd |
| https://www.sennheiser.com/_next/static/chunks/0tpccgzewb7zp.js | 69 KB | 23 KB (33%) | ✓ | 3rd |
| https://www.sennheiser.com/_next/static/chunks/02l79wwqbnvm_.js | 38 KB | 21 KB (56%) | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction96 resources · 14.8 MB · 718 KB savings availableFIX
~717.5 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 96 resources | 14.8 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization16 images, 0 KB saveableREVIEW
CJS Execution CostAction1172ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.sennheiser.com/_next/static/chunks/0tpccgzewb7zp.js | 500ms | 391ms | 6ms | 3rd |
| https://www.sennheiser.com/en-de | 264ms | 19ms | 19ms | 3rd |
| Unattributable | 164ms | 31ms | 0ms | 3rd |
| https://cdn.optimizely.com/js/4875027175178240.js | 99ms | 92ms | 6ms | 3rd |
| https://app.usercentrics.eu/browser-ui/3.99.0/index.module.js | 94ms | 76ms | 0ms | 3rd |
| https://www.sennheiser.com/_next/static/chunks/0xyynutob2tcl.js | 52ms | 22ms | 29ms | 3rd |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading2 fonts (65 KB)PASS
Web fonts
2
65 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
Optimization checklist
- Preload critical fonts (priority=high)
- Use woff2 format for all fonts
- Set font-display to swap, optional, or fallback
- Subset large fonts (≤100 KB each)
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall96 requests over 1890msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.sennheiser.com www.sennheiser.com | Other | 500ms | 69 KB | 33% | €9/mo | Costly |
www.sennheiser.com www.sennheiser.com | Other | 264ms | 59 KB | — | €5/mo | Costly |
Unattributable Unattributable | Other | 164ms | 0 KB | — | €3/mo | Optional |
Optimizely cdn.optimizely.com | A/B Testing | 99ms | 76 KB | 45% | €2/mo | Optional |
app.usercentrics.eu app.usercentrics.eu | Other | 94ms | 121 KB | 44% | €2/mo | Optional |
www.sennheiser.com www.sennheiser.com | Other | 52ms | 365 KB | 95% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.sennheiser.com adds 500ms and costs ~€9/month
- www.sennheiser.com adds 264ms and costs ~€5/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾ ▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
www.sennheiser.com takes 500ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.sennheiser.com takes 264ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
95% of www.sennheiser.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev