  In the case of spatially-revolved helioseismic data (such as MDI, GONG, HMI),
the usual mode-fitting analysis consists of fitting the 2l+1 individual
m-spectra of a given multiplet (n, l) either individually or simultaneously.
Such fitting methods fail to obtain reliable estimates of the mode parameters
(frequency, splitting, ...) when the signal-to-noise ratio (SNR) is low, which
makes those methods not suitable when one wants to look at the low-amplitude,
long-lived solar p modes in the low-frequency range. Instead, Salabert et al.
(2007) developed a new method to extract the mode parameters by adjusting the
rotation- and structure-induced frequency shift for each m-spectrum to minimize
the mode width in the m-averaged spectrum (a "collapsogram"). The m-averaged
spectrum technique, applied to the spatially-resolved GONG and MDI data,
appeared to be a powerful tool for low SNR modes in the low-frequency range.
Another possibility to increase the SNR is to combine data from different
instruments (Garcia et al. 2004a). We present here an adaptation of both
techniques: the "collapsograms" applied to a combination of observations from a
Sun-as-a-star instrument, GOLF, and a disk-imaged one, GONG.
