Problems in spectra plots (seewave)

Dear colleagues:
I have a problem generating sound spectra using the R seewave library. 
When I increase the size of the letters as the referees ask me, I can't 
get the titles to adapt to the rest of the graph. I tried with ggspectro 
and with several options and I don't get anything. The instruction I use 
is this:
espectro<-spectro(a, wl=1024, ovlp=60, oma=rep(0,4), zp=16, 
collevels=seq(-40,0,0.5), scalefontlab=4, 
flim=c(0,15),cexlab=3,scalecexlab=3,scale=TRUE)
Some suggestion?.
Thank you very much in advance

****************************************************************************
  Daniel Pat?n
  Numerical Ecology. Ecology Unit
  Department of Plant Biology, Ecology and Earth Sciences
  Faculty of Sciences. University of Extremadura
  Avda. Elvas s/n 06071 Badajoz (Spain)
  https://orcid.org/0000-0003-2500-3964
  https://cvn.fecyt.es/0000-0003-2500-3964
  http://unex.academia.edu/DanielPatonDominguez
  https://www.researchgate.net/profile/Daniel_Paton/
  https://twitter.com/DendrolabU
  http://sites.google.com/site/numericalecologyuex/home
  https://es.linkedin.com/in/daniel-pat?n-dom?nguez-787546106
****************************************************************************